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diff --git a/debian/trs80faq.html b/debian/trs80faq.html new file mode 100644 index 0000000..b110167 --- /dev/null +++ b/debian/trs80faq.html @@ -0,0 +1,2261 @@ +<HTML> +<HEAD> +<TITLE>TRS-80 Model I/III/4: Frequently Asked Questions</TITLE> +</HEAD> +<body bgcolor="#fff0f5"> + +<H2>TRS-80 Model I/III/4: Frequently Asked Questions</H2> + +Here are a few frequently asked questions on the Radio Shack TRS-80 +Model I, Model III, and Model 4. These are Z-80 based machines that +were first introduced in 1977. The three models were partly +compatible with one another, and incompatible with most everything +else. Today they are of interest only to the nostalgic and a few +folks who have specialized applications that were never ported to +newer machines. The following are questions that people frequently +ask <i>me</i>; your mileage may vary! +This FAQ is available on the Web through the page +<A HREF= +"http://tim-mann.org/trs80.html" +>http://tim-mann.org/trs80.html</A>. + +<pre> +$Id: trs80faq.html,v 1.59 2007/02/21 05:16:37 mann Exp $ +</pre> + +<HR> +<H2>Contents</H2> + +<UL> +<LI><A HREF="#[1]"> + [1] Where can I get TRS-80 software and hardware? + </A></LI> +<li><a href="#[2]"> + [2] Where can I get information to repair or upgrade my TRS-80? + </a></li> +<li><a href="#[3]"> + [3] How can I read my TRS-80 floppy disks in a PC? + </a></li> +<LI><A HREF="#[4]"> + [4] What TRS-80 emulators do you recommend? + </A></LI> +<LI><A HREF="#[5]"> + [5] What is a .DSK file? + </A></LI> +<LI><A HREF="#[6]"> + [6] How can I convert my real TRS-80 floppy disks to .DSK files? + </A></LI> +<LI><A HREF="#[7]"> + [7] How can I convert .DSK files to real TRS-80 floppy disks? + </A></LI> +<LI><A HREF="#[8]"> + [8] How can I get individual files off a .DSK file or TRS-80 + floppy disk? + </A></LI> +<LI><A HREF="#[9]"> + [9] How can I put individual files onto a .DSK file or TRS-80 floppy disk? + </A></LI> +<li><a href="#[10]"> + [10] What do I do with TRS-80 software that comes in .ZIP files? + </a></li> +<li><a href="#[11]"> + [11] What are the system file passwords and password back doors + on TRS-80 operating systems? + </a></li> +<li><a href="#[12]"> + [12] What problems do PC floppy disk controllers have with TRS-80 + disk formats? What problems do different TRS-80 models have with each + other's disk formats? + </a></li> +<li><a href="#[13]"> + [13] How can TRSDOS 2.3 be patched to read single-density disks written by + a Model III, Model 4, or PC? + </a></li> +<li><a href="#[14]"> + [14] What are the differences among single, double, quad, and high + density floppy media? + </a></li> +<li><a href="#[15]"> + [15] Which PC floppy controllers and drives can handle single density (FM)? + </a></li> +<li><a href="#[16]"> + [16] What PC add-on cards can handle single density (FM) and + other unusual formats? + </a></li> +<li><a href="#[17]"> + [17] How can I add lowercase to a TRS-80 Model I? + </a></li> +<li><a href="#[18]"> + [18] My Model 4 or 4P has video problems in Model 4 mode, but + is fine in Model III mode. How can I fix it? + </a></li> +<li><a href="#[19]"> + [19] I want to add or replace TRS-80 floppy disk drives. + What's going on with the setup and cabling? + </a></li> +<li><a href="#[20]"> + [20] What about using high density (1.2MB 5.25-inch or 1.44MB 3.25-inch) + drives on a TRS-80? + </a></li> +<li><a href="#[21]"> + [21] What about using low density (360KB 5.25-inch or 720KB 3.25-inch) + drives on a PC? + </a></li> +<li><a href="#[22]"> + [22] What are some other good references for detailed information + about floppy disks and drives? + </a></li> +<li><a href="#[23]"> + [23] How do I determine what PDRIVE settings to use for a + NEWDOS/80 disk? + </a></li> +<li><a href="#[24]"> + [24] How do I make a bootable double-density Model I LDOS 5.3.1 + system disk from the single-density master disk set? + </a></li> +<li><a href="#[25]"> + [25] What about using 8-inch drives on a PC? + </a></li> +<li><a href="#[26]"> + [26] How can I read the back of a disk that was written in a + flippy drive? + </a></li> +</UL> + +<HR> + +<H3><A NAME="[1]"> + [1] Where can I get TRS-80 software and hardware? +</A></H3> + +<p>A huge collection of TRS-80 software is available for download +from the TRS-80 Revived Pages, +<A HREF="http://www.trs-80.com/" +>http://www.trs-80.com/</A>. + +<p>Most software from Misosys, Logical Systems, Galactic Software +Ltd., Powersoft, and Breeze/QSD is now available for free download by +permission of the copyright owner, Roy Soltoff (owner of Misosys). +See <a href="http://tim-mann.org/trs80.html" +>http://tim-mann.org/trs80.html</a>. + +<p>Computer News 80 has some commercial software and hardware +products, a library of freeware disks, and a small monthly newsletter +that still supports the TRS-80 I/III/4. You can contact them via the +Web at <a href="http://www.ebaystores.com/computernews80/" +>http://www.ebaystores.com/computernews80/</a>. + +<p>M. A. D. Software deals in TRS-80 products. Among other things, +they have upgrades to the Model 4P ROMs and the MODELA/III file (Model +III ROM image). Check out their Web site at <a +href="http://madsoft.lonestar.org/" >http://madsoft.lonestar.org/</a>, +or contact them via email at +madcs@madsoft.lonestar.org or via US mail at: + +<p><address> + M. A. D. Software<br> + P. O. Box 331323<br> + Fort Worth, TX 76133-1323 +</address> + +<p>Archive Software is a small venture run by Cord Coslor. +Cord buys and sells used TRS-80 Model I/III/4 software and hardware +(among other things). Here is his new contact information as of +2-Apr-2001: + +<p><address> + Cord Coslor<br> + Archive Software<br> + 21939 Hernando Ave.<br> + Port Charlotte, FL 33952<br> + (941) 625-1649<br> + e-mail: ArchiveSoftware@juno.com<br> + web: <a href="http://www.archivenews.net" + >www.archivenews.net</a> +</address> + +<p>Ian Mavric of Melbourne, Australia runs "The Right Stuff (aka +TRS-80 Oldtimer Centre)". He deals in both hardware and software. +See his Web page at +<a href="http://www.netspace.net.au/~ianmav/trs80/" +>http://www.netspace.net.au/~ianmav/trs80/</a>. + +<p>There is a page of TRS-80s for sale linked from +<a href="http://www.trs-80.com/">http://www.trs-80.com/</a>. + +<p>You can still order some software from Tandy Software Replacement +and/or Radio Shack Unlimited, formerly Radio Shack National Parts. +You can ask at a store or call Radio Shack at 800-843-7422. I'm told +that you might have to bug people for a while and maybe ask for a +supervisor or someone who's been there longer, before you find someone +who believes this is possible and knows how to do it. The purpose of +Tandy Software Replacement is to supply replacement disks to people +whose originals have been destroyed, so generally they do not provide +manuals or packaging, and the prices are very low. They don't +actually seem to care whether you originally owned the software. +Radio Shack Unlimited also stocks (or can make up) full packages of +some software, including manuals. + +<p>You can try bidding in the <a href="http://www.ebay.com">eBay</a> +auctions. Prices tend to be inflated, though. + +<hr> +<H3><A NAME="[2]"> + [2] Where can I get information to repair or upgrade my TRS-80? +</A></H3> + +<p>More hardware information is starting to appear on the Web these +days. See the TRS-80 links on my Web page, at <a +href="http://tim-mann.org/trs80links.html" +>http://tim-mann.org/trs80links.html</a>, both the "history and +technical data" and "software and documentation downloads" sections. + +<p>You can ask on the newsgroup +<a href="news:comp.sys.tandy">comp.sys.tandy</a>. This is a good +place for TRS-80 software questions too. You might also try searching +back postings to the group with <a href="http://dejanews.com/">Deja +News</a>. + +<p>Also try the sources given in topic <a href="#[1]">[1]</a> to see +if they carry hardware manuals. Tandy Software Replacement or Radio +Shack Unlimited are said to be able to photocopy and sell manuals, but +I haven't tried this. + +<p>Computer News 80 has a mail-in repair service; see topic <a +href="#[1]">[1]</a>. + +<p>Tandy Repair Centers may or may not be able to fix your TRS-80. +There is some danger that they won't know how to find the necessary +parts and information. They don't see a lot of these machines any more. + +<hr> +<H3><A NAME="[3]"> + [3] How can I read my TRS-80 floppy disks in a PC? +</A></H3> + +<p>This is a somewhat complex topic, and much of the rest of this FAQ +is devoted to the details. There are a number of approaches, but I +think the best is to copy the disks to virtual disk image (.DSK) +files, as used by the various TRS-80 emulators; see the next few +topics in this FAQ. Once you have your data in .DSK format, it +will be much easier to work with. You can use an emulator to run the +TRS-80 software that is on the disks, get directory listings, examine +or print the data, extract individual files, etc. + +<p>Another approach that people sometimes try is to run TRSCROSS. +This is an MS-DOS program for reading and writing TRS-80 diskettes +that directly extracts individual files from the disks, without making +a .DSK image. It's a very old program that seems to have trouble +working on modern, fast PCs, and it puts your data into a format that +is not directly usable with emulators. I do not recommend this +approach, but if you really want to try it, TRSCROSS is available from +my <a href="http://tim-mann.org/misosys.html">Misosys software page</a>. + +<p>Another approach that doesn't work well is to try to read the disks +in Linux without using an emulator. The Linux floppy driver is quite +versatile, but (at least as of this writing) no matter how you +configure it, you won't be able to read TRS-80 disks through the +normal open/close/read/write interface that programs like "dd" use. +First, the driver assumes that sector numbering always starts from 1, +but most TRS-80 formats start it from zero. Second, the driver +assumes that all sectors are written with a normal data address mark, +but most TRS-80 formats write some sectors (usually those on the +directory track) with a different DAM. The TRS-80 emulator for Linux +(xtrs) talks to the floppy driver using the low-level "raw command" +interface, which lets it get around these problems. + +<p>Still another approach is to connect a serial or parallel cable +between your PC and a real TRS-80, and transfer the data over that. +This is a lot slower than reading a floppy, but in some cases you can +be stuck doing it when the other approaches discussed below don't +work. Jeff Vavasour's Model I emulator includes instructions on how +to do this with a Model I; see topic <a href="#[4]">[4]</a>. I don't +have any advice beyond that, not having tried this approach myself. + +<hr> +<H3><A NAME="[4]"> + [4] What TRS-80 emulators do you recommend? +</A></H3> + +<p>Under <b>Linux</b> and other <b>Unix</b>-compatible operating systems, I +recommend the <a href="http://tim-mann.org/xtrs.html" >xtrs</a> +Model I/III/4/4P emulator. It should work on any version of Unix with +the X Window System, except that its support for physical floppy disk +drives works only under Linux, and sound works only under Linux or +other systems that have OSS-compatible sound drivers. It is free +software with full source code included. + +<p>Under <b>Windows NT/2000/XP/2003</b>, the following TRS-80 emulators are +available. Due to a limitation of Windows NT family operating +systems, neither one supports physical floppy disk drives, only floppy +images (.DSK files). They are both quite full featured otherwise. +<ul> +<li>Matthew Reed's new <a +href="http://www.arrowweb.com/mkr/">TRS32</a> emulates Models I, III, +and 4. The unregistered shareware version can be downloaded for free, +but omits a few features. The full version costs $69. + +<li>Wade Fincher's <a +href="http://asub.arknet.edu/wade/wintrs80.htm">WinTRS-80</a> +emulates Models I, III, 4, and 4P. +It is downloadable free of charge, but source code is not available. +</ul> + +<p>The TRS-80 emulators available for <b>MS-DOS</b> or <b>Windows 95/98/ME</b> +<i>do</i> support physical floppy drives. I don't think any of them run under +Windows NT/2000/XP/2003 at all, however. +<ul> + <li><a href="http://discover-net.net/~dmkeil/" >David Keil's Model I + emulator</a>. The full version can be + downloaded free of charge, but a $10 contribution is requested + if you find it useful. + <li><a href="http://discover-net.net/~dmkeil/" >David Keil's Model III/4/4P + emulator</a>. The full version can be + downloaded free of charge, but a $10 contribution is requested + if you find it useful. + <li><a href="http://www.arrowweb.com/mkr/" >Matthew Reed's Model + I/III emulator</a>. The unregistered shareware + version can be downloaded free of charge, but emulates the + Model I only. The registered version costs $29. + <li><a href="http://www.arrowweb.com/mkr/" >Matthew Reed's Model 4 + emulator</a>. The unregistered shareware version can + be downloaded free of charge, but omits Model III mode and a + few other features. The registered version costs $49. + <li><a href="http://www.vavasour.ca/jeff/trs80.html" + >Jeff Vavasour's Model I emulator</a>. This is now + downloadable free of charge. + <li>Jeff Vavasour's Model III/4 emulator</a>. This is available by + mail order from <a href="http://www.ebaystores.com/computernews80/" + >Computer News 80</a>. The price is $59.95. +</ul> + +<hr> +<H3><A NAME="[5]"> + [5] What is a .DSK file? +</A></H3> + +<p>A .DSK file is an image of a TRS-80 floppy disk in a file. They +are used by TRS-80 emulators. + +<p>Warning: There are three kinds of .DSK files with different +internal formats, one that originated with Jeff Vavasour's Model I +emulator (JV1), one that originated with his Model III/4 emulator +(JV3), and one that originated with David Keil's emulators (DMK). Each +one adds support for more TRS-80 disk formats. Each of Jeff's +emulators works only with the kind of .DSK file that was designed for +it. Matthew Reed's emulators work with JV1 and JV3 +transparently. David Keil's emulators and <strong>xtrs</strong> +work with all three kinds. + +<p>Technical details of the JV1 and JV3 formats are now available from +my Web page, <a +href="http://tim-mann.org/trs80/dskspec.html" +>http://tim-mann.org/trs80/dskspec.html</a>. +Technical details of the DMK format are available from David Keil's +Web page, <a +href="http://discover-net.net/~dmkeil/trs80/trstech.htm#Technical-DMK-disks" +>http://discover-net.net/~dmkeil/trs80/trstech.htm#Technical-DMK-disks</a>. + +<hr> +<H3><A NAME="[6]"> + [6] How can I convert my real TRS-80 floppy disks to .DSK files? +</A></H3> + +<p>There are several possibilities: + +<p>(A) One way is to transfer data over the TRS-80's serial port or +printer port. That's probably the best way if you have a Model I, +because a stock Model I can read and write only single density, but +many PCs cannot deal with single density (see topic <a +href="#[12]">[12]</a>). Jeff Vavasour's Model I emulator includes +instructions on how to do this; see topic <a href="#[4]">[4]</a>. + +<p>(B) A faster and more convenient way, if you can get it to work, is to +read the disks in a PC with a 5.25-inch floppy drive. Under MS-DOS or MS +Windows, try Matthew Reed's freeware READDISK program. See <a +href="http://www.arrowweb.com/mkr/readdisk_doc.html" +>http://www.arrowweb.com/mkr/readdisk_doc.html</a>. + +<p>(C)If you have problems with READDISK or you are using +Linux, you can copy the disks with an emulator, as follows. + +<ol> +<li>Get a TRS-80 emulator that supports both .DSK files and real floppy +drives. See topic <a href="#[4]">[4]</a>. Read the emulator's +instructions and get it running.</li> + +<li>Find a PC with a real 5.25-inch floppy drive attached. In theory, a +40-track DD drive is best if your TRS-80 had 40-track or 35-track +drives, but you can use 80-track HD drives too. (On a PC, 40-track DD +drives are usually called 180KB or 360KB drives, depending on whether +they are single or double sided.) The trouble with this theory is +that DD drives may not work with some emulators (see topic +<a href="#[21]">[21]</a>), and if your DD drive +is a pullout from a TRS-80, you may have difficulty cabling and jumpering +it correctly for a PC.</li> + +<li>Configure the emulator with an LDOS or other operating system .DSK +file as drive :0, a new, empty .DSK file as drive :1, and the real +drive as drive :2. If you are using a Model I emulator with LDOS, +note that Model I LDOS comes on two .DSK files, so configure the +emulator with the second one (LDOSXTRA.DSK) as drive :3. Note: +never try to use drive :3 for a double-sided disk (read or virtual) on +the Model I; a limitation of the Model I hardware (which the emulators +have no choice but to emulate faithfully) makes this fail to work.</li> + +<li>Boot the emulated machine. Model I LDOS requires an extra driver +to deal with double density, so if you are using it, type FDUBL to the +emulator after booting.</li> + +<li>Put the floppy into the real drive and copy it to the emulated +drive (.DSK) file. If you are using LDOS 5.3.1, the command is QFB :2 +:1. On LS-DOS 6.3.1, the command is DISKCOPY :2 :1. Both those +commands format the floppy automatically. +</li> </ol> + +<p>The above instructions assume that the disk is in a format that can +be copied by LDOS. For TRSDOS 1.3 and NEWDOS/80 disks that LDOS +doesn't understand, you can get a TRSDOS 1.3 or NEWDOS/80 image from +<a href="http://www.trs-80.com" >http://www.trs-80.com</a>, use that +as the operating system in the above procedure, and use appropriate +TRSDOS 1.3 or NEWDOS/80 commands to copy the disk. Sorry; I can't +help with the details, but see topic <a href="#[23]">[23]</a> for more +help with NEWDOS/80. + +<p>(D) For copy-protected disks (or normal disks, actually), you can also +try running one of the many TRS-80 copy utilities on an emulator, +copying from a real PC drive to a .DSK image. This will work if the +copy utility is compatible with the emulator and the physical disk can +be read by a PC floppy controller. The procedure is generally similar +to the instructions outlined above, but the details depend on which +copy utility you're using. I've had good results with SuperUtility +(available from <a href="http://tim-mann.org/misosys.html" +>http://tim-mann.org/misosys.html</a>) running under xtrs, and I +think it runs well under David Keil's emulator too. If you are using +Model I SuperUtility, be sure to set the emulator to emulate either a +Tandy or Percom double density adapter, not both at once. The CopyCat +program available from <a href="http://discover-net.net/~dmkeil/" +>David Keil's web site</a> is also handy, as it only copies disks and +is much more automated than SuperUtility. CopyCat works well under +David Keil's emulator and under xtrs version 4.9 or later. Other copy +utilities that are sometimes useful include Trakcess and HyperZap, +though HyperZap has problems analyzing real disks when run under an +emulator. + +<p>(E) Another method is to buy a Catweasel universal floppy +controller card and copy the disks with it using the cw2dmk program +from my Catweasel Tools. This method is good for disks that your PC +can't read. See topic <a href="#[12]">[12]</a> for some reasons why +your PC may not be able to read certain TRS-80 disks. See topic <a +href="#[16]">[16]</a> and <a +href="http://tim-mann.org/catweasel.html" +>http://tim-mann.org/catweasel.html</a> for more +information on the Catweasel and the tools. + +<hr> +<H3><A NAME="[7]"> + [7] How can I convert .DSK files to real TRS-80 floppy disks? +</A></H3> + +<p>There are several possibilities: + +<p>(A) One way would be to transfer data from your newer computer to a +real TRS-80 through its serial port or printer port. That may be the +only way if you have a Model I, because a stock Model I can read and +write only single density, but many PCs cannot deal with single +density (see topic <a href="#[12]">[12]</a>). However, I don't know +of any software for transferring data <i>to</i> the TRS-80 Model I through a +serial or parallel port. (Kermit did exist for the Model 4, and you may +be able to find XMODEM or the like, but I can't help with them.) + +<p>(B) A faster and more convenient way, if you can get it to work, is +to write the disks in a PC with a 5.25-inch floppy drive. If you have Linux +on your PC and your disk is a standard double-density format (40 or 80 +tracks, 1 or 2 sides), you can use the programs trsfmt and diskdmp by +Tony Duell, available from +<a href= +"http://tim-mann.org/trs80/trsdsk.tar.gz" +>http://tim-mann.org/trs80/trsdsk.tar.gz</a>. +See the documentation included in the tar file. If you don't understand +what to do with .tar.gz files, see the next method instead. + +<p>(C) A more general way to write TRS-80 floppy disks in a PC with a +5.25-inch floppy drive is to use an emulator. Suitable emulators are +available for both Linux and DOS or Windows. Here is a procedure you +can follow. + +<ol> +<li>Get a TRS-80 emulator that supports both .DSK files and real +floppy drives. See topic <a href="#[4]">[4]</a>. Please don't +say, "But I don't need an emulator, I have a real machine!" You need +an emulator to run this procedure, and they are nice to have anyway, +so get one.</li> + +<li>Get the files working for you in the emulator as .DSK files. Read +the instructions for the emulator to find out how to do this.</li> + +<li>Find a PC with a real 5.25-inch floppy drive attached. In theory, a +40-track DD drive is best if your TRS-80 had 40-track or 35-track +drives, but you can use 80-track HD drives too. (On a PC, 40-track DD +drives are usually called 180KB or 360KB drives, depending on whether +they are single or double sided.) The trouble with this theory is +that DD drives may not work with some emulators, and if your DD drive +is a pullout from a TRS-80, you may have difficulty cabling and jumpering +it correctly for a PC.</li> + +<li>Bulk-erase a 5.25-inch floppy, preferably using an AC bulk tape eraser as +sold by Radio Shack and others. You may be able to omit this step if +you are using a 40-track drive, but it's a good idea to do it anyway. +It is best to use floppies that are rated for double density or quad +density, not high density. High density floppies may work in a +pinch, but don't expect double density data to stay stable on them for +a long time.</li> + +<li>Configure the emulator with an LDOS or other operating system .DSK +file as drive :0, the .DSK file you want to convert as drive :1, and +the real drive as drive :2. If you are using a Model I emulator with +LDOS, note that Model I LDOS comes on two .DSK files, so configure the +emulator with the second one (LDOSXTRA.DSK) as drive :3. Note: +never try to use drive :3 for a double-sided disk (read or virtual) on +the Model I; a limitation of the Model I hardware (which the emulators +have no choice but to emulate faithfully) makes this fail to work.</li> + +<li>Boot the emulated machine. Model I LDOS requires an extra driver +to deal with double density, so if you are using it, type FDUBL to the +emulator after booting.</li> + +<li>Put the floppy into the real drive and copy the emulated drive +(.DSK) file to it. If you are using LDOS 5.3.1, the command is QFB :1 +:2. On LS-DOS 6.3.1, the command is DISKCOPY :1 :2. Both those +commands format the floppy automatically. +</li> </ol> + +<p>The above instructions assume that the disk is in a format that can +be copied by LDOS. For TRSDOS 1.3 and NEWDOS/80 disks that LDOS +doesn't understand, you can get a TRSDOS 1.3 or NEWDOS/80 image from +<a href="http://www.trs-80.com" >http://www.trs-80.com</a>, use that +as the operating system in the above procedure, and use appropriate +TRSDOS 1.3 or NEWDOS/80 commands to copy the disk. Sorry; I can't +help with the details, but see topic <a href="#[23]">[23]</a> for more +help with NEWDOS/80. + +<p>(D) For copy-protected disks (or normal disks, actually), you can also +try running one of the many TRS-80 copy utilities on an emulator, +copying from a .DSK image to a real PC disk drive. This will work if the +copy utility is compatible with the emulator and the physical disk format +can be written by your PC floppy controller. +The procedure is generally similar +to the instructions outlined above, but the details depend on which +copy utility you're using. I've had good results with SuperUtility +(available from <a href="http://tim-mann.org/misosys.html" +>http://tim-mann.org/misosys.html</a>) running under xtrs, and I +think it runs well under David Keil's emulator too. If you are using +Model I SuperUtility, be sure to set the emulator to emulate either a +Tandy or Percom double density adapter, not both at once. The CopyCat +program available from <a href="http://discover-net.net/~dmkeil/" +>David Keil's web site</a> is also handy, as it only copies disks and +is much more automated than SuperUtility. CopyCat works well under +David Keil's emulator and under xtrs version 4.9 or later. Other copy +utilities that are sometimes useful include Trakcess and HyperZap. + +<p>(E) Another method is to buy a Catweasel universal floppy +controller card and copy the disks with it using the dmk2cw program +from my Catweasel Tools. This method is good +for disk formats that your PC can't write. See topic <a +href="#[12]">[12]</a> for some reasons why your PC may not be able to +write certain kinds of TRS-80 disks. See topic <a +href="#[16]">[16]</a> and <a +href="http://tim-mann.org/catweasel.html" +>http://tim-mann.org/catweasel.html</a> for more +information on the Catweasel and the tools. + +<p>(F) If you need a copy of LS-DOS 6.3.1 on a real floppy and have no +other way to do it, M. A. D. Software will make a diskette for you for +$7.50 US plus shipping. Paper documentation is included. You can +request a single-sided or double-sided floppy. This service was +announced on 19 January 1998. See topic <a href="#[1]">[1]</a> for +contact information. + +<hr> +<H3><A NAME="[8]"> + [8] How can I get individual files off a .DSK file or TRS-80 + floppy disk? +</A></H3> + +<p>Most of the TRS-80 emulators have programs for doing this. Read +the instructions for your emulator to find out how to use them. +Sometimes the program runs on the emulated Z-80 (a /CMD file); other +times it runs on the host operating system (an .EXE file). + +<p>Under Jeff Vavasour's Model I emulator, the relevant program is +VREAD.EXE. Under Jeff's Model III/4 emulator, it is EXPORT/CMD. +Under Matthew Reed's emulators, the program is TRSREAD.EXE and is +available only with registration. Under xtrs and David Keil's +emulators, the program is called EXPORT/CMD (not the same program as +Jeff's). + +<hr> +<H3><A NAME="[9]"> + [9] How can I put individual files onto a .DSK + file or TRS-80 floppy disk? +</A></H3> + +<p>Most of the TRS-80 emulators have programs for doing this. Read +the instructions for your emulator to find out how to use them. +Sometimes the program runs on the emulated Z-80 (a /CMD file); other +times it runs on the host operating system (an .EXE file). + +<p>Under Jeff Vavasour's Model I emulator, the relevant program is +VWRITE.EXE. Under Jeff's Model III/4 emulator, it is IMPORT/CMD. +Under Matthew Reed's Model I/III emulator, the program is TRSWRITE.EXE +and is available only with the registered version. Under xtrs and +David Keil's emulators, the program is called IMPORT/CMD (not the same +program as Jeff's). + +<hr> +<H3><A NAME="[10]"> + [10] What do I do with TRS-80 software that comes in .ZIP files? +</A></H3> + +<p>Some TRS-80 software you will find on the Web is supplied in .ZIP +archive files. You need to unzip these files to unpack their +contents. There actually are unzip programs that run on a TRS-80, but +they're slow and may not support all the compression types used by +modern zip programs. So you'll generally want to unzip these archives +on on your PC or Unix box. You can get free unzip programs from <a +href="http://www.info-zip.org/pub/infozip/" +>http://www.info-zip.org/pub/infozip/</a>. + +<p>Within some .ZIP archives is a .DSK file. This is an emulated +floppy disk file. See topic <a href="#[5]">[5]</a> and the rest of +this FAQ for instructions on how to deal with .DSK files. + +<p>Other .ZIP archives contain individual files extracted from TRS-80 +disks. You can use these with an emulated (or real) TRS-80 by copying +the files onto a .DSK file or a real floppy. See topic <a +href="#[9]">[9]</a> for instructions. + +<p>Some .ZIP archives of TRS-80 software may contain both a .DSK +and the individual files extracted from it. This is perhaps the most +convenient form, but obviously takes up twice as much space as either +of the others. + +<hr> +<H3><A NAME="[11]"> + [11] What are the system file passwords and password back doors + on TRS-80 operating systems? +</A></H3> + +<p>The table below is based partly on documentation and partly on +actual test. Where a filename matches more than one pattern, use the +first one that matches. If a password doesn't work, try others from +the table and let me know of the error. If you have password +information for other Model I/III/4 operating systems, let me know. +The values in the TRSDOS 6 column should also work for versions of +LS-DOS prior to 6.3.1. + +<pre> +Files LDOS 5.1.0 LDOS 5.3.1 TRSDOS 6 LS-DOS 6.3.1 +----- ---------- ---------- -------- ------------ +basic/* (unused) basic basic basic +lbasic/* basic (unused) (unused) (unused) +config/sys ccc ccc ccc ccc +*/sys wolves system lsidos system6 +*/flt gsltd filter filter filter +*/dvr gsltd driver driver driver +*/dct rrw3 driver utility driver or utility +*/cmd rrw3 utility utility utility +*/hlp (unused) help (unused) help +back door rs0lt0ff rs0lt0ff (nflag$ bit7) (nflag$ bit7) +</pre> + +The password listed as "back door" gives you access to all files +regardless of what their real passwords are. It's documented! I +confirmed by looking at the source code that TRSDOS/LS-DOS 6 has no +such password, but I found that later versions of it have another, +undocumented back door: if you turn on bit 7 of NFLAG$, all file +password checking is disabled. The command MEMORY (A="N", B=128) will +do this. This back door can be found in TRSDOS 6.2 and LS-DOS 6.3.1, +but not in TRSDOS 6.1.2. + +<p>Model I TRSDOS 2.3 also has +a back door password; the originally intended password is unknown, but +the string "ubett" hashes to the correct value and can be used. +The strings "f3gum", "nv36", and many others also work. +VTOS 3.0 also has such a back door; the password "hadu" can be used. + +<p>The password "password" is a standard default in the TRS-80 world. +If you're insistently prompted for a password in a situation where you +don't think a password should be needed, try "password". + +<p>Another way to reconstruct TRS-80 passwords is through exhaustive +search. This is quite fast because TRS-80 operating systems hash their +passwords down to 16-bit values, so you need only find some password +that hashes to the same value, not the exact original password. Here +is a C program to do that. + +<pre> +/* trspwhash + * Usage: trspwhash password // Hash a password + * trspwhash -u 0xhash // Unhash a password to letters + * trspwhash -n 0xhash // Unhash a password to letters and digits + */ +#include <stdio.h> + +unsigned int +pwhash(unsigned char pw[8]) +{ + unsigned char *p = &pw[7]; + unsigned int count = 8; + unsigned int hl, t1, t2; + + hl = 0xffff; + do { + t1 = hl & 0x07; + t2 = hl & 0xff; + hl = (t1 << 13) ^ (t1 << 9) ^ (t1 << 2) ^ + (t2 << 8) ^ (t2 << 4) ^ (t2 >> 3) ^ + (hl >> 8) ^ (*p-- << 8); + } while (--count); + return hl; +} + +void +usage() +{ + fprintf(stderr, "usage: trspwhash [-u | -n] arg\n"); + exit(1); +} + +int +main(int argc, char **argv) +{ + unsigned int goal; + unsigned char pw[16]; + int i; + if (argc == 2) { + strncpy(pw, argv[1], 8); + pw[8] = '\0'; + strcat(pw, " "); + for (i = 0; i < 8; i++) { + if (islower(pw[i])) pw[i] = toupper(pw[i]); + } + printf("%04x\n", pwhash(pw)); + } else if (argc == 3 && strcmp(argv[1], "-u") == 0) { + goal = strtoul(argv[2], (void*)0, 0); + strcpy(pw, " "); + for (;;) { + if (pwhash(pw) == goal) printf("%s\n", pw); + i = 0; + for (;;) { + switch (pw[i]) { + case ' ': + pw[i] = 'A'; + break; + case 'Z': + pw[i] = 'A'; + i++; + if (i == 8) exit(0); + continue; + default: + pw[i]++; + break; + } + break; + } + } + } else if (argc == 3 && strcmp(argv[1], "-n") == 0) { + goal = strtoul(argv[2], (void*)0, 0); + strcpy(pw, " "); + for (;;) { + if (pwhash(pw) == goal) printf("%s\n", pw); + i = 0; + for (;;) { + switch (pw[i]) { + case ' ': + pw[i] = 'A'; + break; + case 'Z': + pw[i] = '0'; + break; + case '9': + pw[i] = 'A'; + i++; + if (i == 8) exit(0); + continue; + default: + pw[i]++; + break; + } + break; + } + } + } else { + usage(); + } + return 0; +} +</pre> + +<hr> +<h3><a name="[12]"> + [12] What problems do PC floppy disk controllers have with TRS-80 + disk formats? What problems do different TRS-80 models have with each + other's disk formats? +</a></h3> + +<p>The Western Digital 177x/179x floppy disk controllers that were +used in TRS-80s have some capabilities that PC disk controllers +generally lack. The executive summary is that (1) many standard PC +floppy controllers can't handle single density at all, (2) even those +that can handle single density generally cannot read the directory +track on a Model I TRSDOS disk, and (3) there can also be problems +reading double density disks. Here are more details. + +<p>Many PCs cannot handle single density (FM) encoding. The original +Model I used single density exclusively, and even a Model I with a +double density adaptor requires a single density boot sector on system +disks. The original IBM PC controller required extra outboard +components to support clock/data separation for single density, but +IBM left them off to reduce their manufacturing costs. (So I'm told; +I wasn't involved with PCs in that era.) This started the tradition +of leaving out single density support in PCs. Modern PCs use more +highly integrated IO chips that include data separation on the chip, +but many still omit single density support. See topic <a +href="#[15]">[15]</a> for a rundown on what PC controllers support +single density and topic <a href="#[16]">[16]</a> for other hardware +solutions that are available. + +<p>The WD1771, used in the TRS-80 Model I, is able to read and write +single-density sectors with nonstandard data address marks (DAMs) 0xF9 +and 0xFA, as well as the standard ones 0xFB (data) and 0xF8 (deleted +data). The WD1791/1793 and later chips, used in the Model III and 4, +can read all such sectors, but cannot distinguish between 0xFB +and 0xFA or between 0xF9 and 0xF8. Model I's with double density adaptors +have *both* controllers, and use the 1771 for single density, so they +are fully compatible with stock Model I's. PC disk controllers, even +those that do single density, cannot read sectors that use the 0xFA or +0xF9 DAM at all. (I have actually tested this only with 0xFA on a +PC87306. I'd welcome corrections if other standard PC controllers can +handle these data address marks.) See topic <a href="#[16]">[16]</a> +for devices that can read these disks. + +<p>These differences would be no problem if Model I software did not +actually use the nonstandard DAMs, but unfortunately, it does. In +particular, Model I TRSDOS 2.x distinguishes between normal data +sectors and directory sectors by using 0xFB for the former and 0xFA +for the latter. On Model III/4 TRSDOS-like systems, where 0xFA is not +fully supported, 0xF8 is used instead. +Some later Model I systems (such as LDOS 5.0.2 and later) also +switched to 0xF8 on the directory to allow for direct media +compatibility with the Model III/4, while others stuck with 0xFA for +direct Model I TRSDOS compatibility. Patches for TRSDOS 2.3 were +developed that allow it to read and/or write 0xF8 directory sectors, +but they were not widely used. (See topic <a href="#[13]">[13]</a>.) +Special software is supplied with +Model III/4 operating systems that allows them to read Model I disks +and/or convert them to Model III/4 format. (The REPAIR command on +LDOS is an example of the latter.) No such software can work on a PC +controller, however, because the 0xFA sectors cannot be read at all. + +<p>There are also many gratuitous format differences amongst the +various TRSDOS-like TRS-80 operating systems. For most of the +systems, a single-density, single-sided, 35-track disk is a common +denominator, except for the DAM problem just discussed. Adding more +tracks is usually not a problem, though some systems may insist that +the directory remain on track 17, while others put the directory +location in track 0, sector 0, byte 2. The various systems diverged +in the way they generalized the format to work with double density and +other larger drives. The main streams were LDOS, NEWDOS, and Model +III TRSDOS 1.3. LDOS uses a variable number of sectors per granule +(allocation unit) that must evenly divide the number of sectors per +track, and uses exactly one cylinder for the dirctory. I believe +NEWDOS always uses 5 sectors per allocation unit, but allows varying +the packing of granules onto the disk and the number of granules used +for the directory. Model III TRSDOS 1.3 made a large number of +unnecessary changes to the format; it was clearly inspired by the Model +I format, but it is not a compatible extension. + +<p>Many PC disk controllers have difficulty reading double density +disks formatted by older releases of TRS-80 operating systems, even +with the proper software on the PC. Many TRS-80 operating systems +formatted the disks with too short a gap between the index hole and +the first sector. Late releases of the +Model III and 4 operating systems were corrected to format floppies +with the proper gap lengths. + +<p>Working around the index hole problem can be tricky. With some +drive/controller combinations, it may work to put a piece of tape over +the index hole, but this is not usually successful. Another +possibility is to read the disk with a Catweasel controller, if you +have one; see topic <a href="#[16]">[16]</a>. +Here are instructions for another approach, from Amardeep S. Chana: + +<ol> +<li>Locate wire number 8 in your floppy disk cable. Wire 1 normally +has a colored stripe, and the wires are numbered sequentially from +there. + +<li>Cut this wire and install a switch so you can connect and +disconnect this wire easily. + +<li>Use one of the more reliable pieces of software to attempt a read +on a real 360K drive: + <ol> + <li>xtrs + <li>DMK emulator + <li>Anadisk or Teledisk + </ol> +READDISK is not very reliable; it is too sensitive to +controller/drive combinations. + +<li>First attempt a read with the switch closed. You will get an +error. Then open the switch and retry. If it is a post index sector +gap problem, this will fix it. + +<li>Note that you must always first try with switch closed and then +retry. The software doesn't initialize the controller properly if you +just always leave the switch open. That wire is the index sense line. +After at least one pulse has been detected, the system no longer needs +index pulses for reads and the rest of the diskette should read fine. +</ol> + +<p>Nick Andrew adds that with older drives (such as original TRS-80 +drives), the drive itself does not need to see the index pulse, but +the PC controller may still need to see at least one pulse to get +started. In this case you can do without the switch; instead, insert +a piece of cardboard alongside the disk after the first attempted +access, positioning it so as to block the index hole sensor. + +<hr> <h3><a name="[13]"> [13] How can TRSDOS 2.3 be patched to read +single-density disks written by a Model III, Model 4, or PC? </a></h3> + +There is a one-byte patch to TRSDOS 2.3 that allows it to read +disks written with standard data address marks (0xF8 and 0xFB instead +of 0xFA and 0xFB; see topic <a href="#[12]">[12]</a>). If you can +find a PC that supports single density (many do not), you could use an +emulator to make Model I disks on it, which you could then read on the +Model I with the help of this patch. The patch is also useful if for +some reason you need to make Model I disks on a Model III or 4. For +instance, suppose you have a PC that can't write single density, but +you also have a real Model III or 4, which can. In that case, you could +copy software to a double density disk on the PC, then copy the double +density disk to single density on the Model III or 4. + +Here's a description of the patch, from the Misosys EDAS manual. +(EDAS was distributed on a Model III/4-compatible disk that Model I +TRSDOS couldn't read without the patch.) If you want to apply the +patch on a Model III or 4 before moving the disk over to a Model I, +you can use Method (1), changing the drive number in line 10 as +needed. <b>New:</b> I've also added a section to Method (1) that will +let the modified disk boot even if its own directory track has 0xF8 +data address marks. + +<h4>Model I TRSDOS 2.3 Patch</h4> + +<p>Model I TRSDOS users will find difficulty in reading the distribution +disk due to the data address mark used for the directory. Therefore, before +making a BACKUP or copying EDAS files from the diskette, you will need to +change one byte of the TRSDOS 2.3 disk driver using one of the following +three methods. This change will not affect the operation of your TRSDOS. + +<p>Method (1) directly modifies the system diskette with a patch. To +prepare for this patch, obtain a fresh BACKUP of your TRSDOS 2.3 to use for +this operation. Then enter the following BASIC program and RUN it. After you +RUN the program, re-BOOT your TRSDOS diskette to correct the byte in memory. + +<pre> + 10 OPEN"R",1,"SYS0/SYS.WKIA:0" + 20 FIELD 1,171 AS R1$, 1 AS RS$, 84 AS R2$ + 30 GET 1,3: LSET RS$="<": PUT 1,3: CLOSE +</pre> + +<p><i>Added 10-18-2000:</i> If you are using this patch on a TRSDOS +2.3 disk that itself has 0xF8 data address marks, the disk will not +boot unless you also patch the boot sector. You can do so by adding +the following lines to the program. Methods (2) and (3) will not work +for this purpose. You might get the message "INTERNAL ERROR IN LINE +60" when you run the program, for unknown reasons, but it works anyway. + +<pre> + 40 OPEN"R",1,"BOOT/SYS.WKIA:0" + 50 FIELD 1,220 AS R1$, 1 AS RS$, 35 AS R2$ + 60 GET 1,1: LSET RS$=CHR$(28): PUT 1,1: CLOSE +</pre> + +<p>Method (2) uses DEBUG to change the byte in memory. Use this if you do +not want to patch your TRSDOS system diskette and are familiar with DEBUG. + +<ol> + <li>At TRSDOS Ready, type DEBUG followed by <ENTER>. + <li>Depress the <BREAK> key to enter the DEBUGger. + <li>Type M46B0 followed by the <SPACE> bar. + <li>Type 3C followed by <ENTER>. + <li>Type G402D followed by <ENTER>. +</ol> + +<p>Method (3) uses a POKE from BASIC to change the value directly in +memory. This procedure is as follows: + +<ol> + <li>Enter BASIC (files = 0, protect no memory) + <li>Type POKE &H46B0,60 followed by <ENTER>. + <li>Type CMD"S" followed by <ENTER>. +</ol> + +<hr> <h3><a name="[14]"> [14] What are the differences among single, +double, quad, and high density floppy media? </a></h3> + +<p>There is essentially no difference between single and double +density media (if you can actually find any single density media +anymore). Double density media has been tested and certified for +double density recording, which is slightly more demanding than single +density recording; conceivably, a dropout that might not be noticed in +single density could be a problem in double density. In practice, +though, I suspect that back in the days when manufacturers sold both +DD and SD media, the media came off the same production line and the +SD media would have met the DD standard nearly all the time. + +<p>"Quad density" 5.25-inch media is certified for double density recording +at 80 tracks per side rather than 40 tracks per side. This is quite +different from "high density," discussed below. 80 TPS quad density +media should work fine at 40 TPS double density. I've been told that +there can be problems using 40 TPS double density media at 80 TPS quad +density; I believe the person who told me this, but neither of us +really knows the reason. All 3.5-inch media is certified for 80 TPS. + +<p>You will also sometimes see media labelled as one-sided or +two-sided. Both types have magnetic material on both sides, but on +the disks advertised as one-sided, the second side may not have been +tested. It's even possible, though unlikely, that the second side was +tested and failed. + +<p>Occasionally you'll find a "flippy" 5.25-inch disk. Such a disk +can be recorded on both sides by removing it from the drive and +flipping it over. It has two separate write-protect notches and two +separate index hole cutouts in the jacket. Sometimes users would make +their own flippy disks with a hole punch. + +<p>There were also a few "flippy drives" made. These had two +write-protect sensors and two index-hole sensors, and they could thus +read and write on the reverse side of an ordinary diskette inserted +into the drive upside-down. If you have disks written in a flippy +drive but you don't have a flippy drive, the reverse side will be +quite hard to read. See topic <a href="#[26]">[26]</a> for ways to do +it. + +<p>"High density" media is very different, and should not be +interchanged with single/double/quad density media. It has different +magnetic properties (higher coercivity, requiring a higher write +current from the disk drive). If you try to format DD media as HD, +the media will be too strongly magnetized and bleed-through can occur, +garbling your data either immediately or after the disk has sat on the +shelf for a while. Such a disk may also be difficult to erase and +rewrite with new data. Similarly, formatting HD media as DD is not a +good idea either; the media will be too weakly magnetized, and your +data may be completely unreadable or may fade away after a while. +These problems are worse on 5.25-inch disks than on 3.5-inch disks because the +difference in coercivity is greater for 5.25-inch media, but they exist +for both types of disk. + +<p>You can distinguish between 3.5-inch HD and DD media by looking for a +hole in the jacket on the opposite edge from the write-enable hole; HD +media has the extra hole, while DD media does not. You cannot +reliably distinguish between 5.25-inch HD and DD media if they are not +labelled. There are a couple of ways of guessing: DD media usually +has a hub reinforcing ring (but not always), while HD media generally +does not. The color of the media also tends to be different; HD media +is darker. + +<hr> <h3><a name="[15]">[15] Which PC floppy controllers and drives can handle +single density (FM)? +</a></h3> + +<p>Some folks will tell you that you need an older PC to get single +density (FM) support. This is wrong. The floppy disk +<strong>controllers</strong> in many PCs being produced today support +FM, and many older ones do not. Some controllers will support FM on +all floppy <strong>drives</strong>, while other controllers have +problems with 5.25-inch 1.2MB HD drives and may require you to change a +jumper in the drive or (more likely) use a 5.25-inch 360K DD drive instead. + +<p>If you need to read and write single density disks, the best thing +to do is to try it on the PCs that you have available and see if you +can find one where it works. This is more accurate and usually easier +method than opening up the box and peering at the part number on the +FDC or SuperIO chip (which might not give you a definite answer +anyway). If you can't find one that works, the information below +and in topic <a href="#[16]">[16]</a> may be of some help. + +<p>The detailed information below was gleaned from newsgroup +and Classic Computer mailing list postings by Amardeep S. Chana, Don +Maslin, Pete Cervasio, Allison Parent, Tony Duell, Nick +Andrew, and Knut Roll-Lund, together with some knowledge of my own. +I've liberally borrowed from their words for this answer. Don't take +this listing as absolute truth; in particular, some of the posters +were not in full agreement on some points! Feel free to send +additions or corrections if you have some information. + +<p><strong>Controllers</strong> The answer to the question "does floppy +disk controller chip X support single density (FM)?" can be "yes", +"no", or "implementation dependent" (that is, "maybe"). With early +controllers, the answer was "maybe", because more external components +were needed to handle data separation for both FM and MFM than for MFM +alone. As mentioned in topic <a href="#[12]">[12]</a>, the original +IBM PC omitted the external components needed to support FM, and many +later compatibles followed suit. Modern controllers typically +integrate data separation on the main chip, but some support FM and +some do not. It seems that in some cases, a PC may be able to read +single density but not write it, or it may be able to read and write +but not format; these behaviors may depend on external components, not +just the controller chip. + +<p>Note: if you are going to use this information, do not rely on +software to identify your FDC chip. Open the box and look. Newer +"compatible" chips often look to software like older chips, but the +status of their FM support may be different. +Also, be aware that the information below may be incomplete or wrong in +some details. If you know more, send mail. + +<p><strong>Drives</strong> In principle, all floppy disk drives support +single density; the drive cannot tell whether you are giving it FM or +MFM encoded data. However, it seems that some controllers cannot do +FM on 5.25-inch drives that spin at 360 RPM, only on drives that spin at +300 RPM. Doing FM on a 360 RPM 5.25-inch drive requires a data rate of +150 Kb/s, which apparently is not implemented in some controllers. +Most 5.25-inch 1.2MB HD drives spin at 360 RPM at all times, but some are +dual spindle speed. A dual spindle speed drive spins at 360 RPM for +HD but slows down to 300 RPM for SD and DD. Teac 5.25-inch drives can +generally be set for dual spindle speed by changing a jumper, but +other brands may not have this ability. + +<p>Unfortunately, we did not understand the rotation speed issue when +gathering most of the information below. It's quite possible that +some controller that are recorded as not supporting FM at all were +actually tried only with 360 RPM 5.25-inch drives, and would have worked with +300 RPM 5.25-inch drives. It's also possible that some controllers that are +recorded as supporting FM were only tried with 300 RPM 5.25-inch drives and +won't work with 360 RPM 5.25-inch drives. This could also explain why different +people reported inconsistent results for some controllers. + +<h4>Will not support single density (FM)</h4> +<ul> +<li>Intel 82078 +<li>Intel 82091AA Super I/O +<li>Goldstar Prime 1 (?) +<li>NS PC87332 Super I/O (?) +<li>Motorola MCS3201FN (?) +</ul> + +<p>The Intel 82078 data sheet implies that the parts do not support +single density. The MFM bit in its command set is defined as (1 = +double density mode, 0 = reserved). On PC FDCs that do support FM, +setting this bit to 0 selects FM. Tim had a system that used a 82078 +on the motherboard, and FM did not work on it (he tried only a 360 RPM +drive). Similar wording is used on the 82091AA data sheet. + +<p>Amardeep has a card with the Goldstar "Prime 1" chip and +it does not read or write FM. + +<p>The NS PC87332 data sheet is not specific about whether FM is +supported. Amardeep tested the PC87332 and it failed to support FM in +a Dell XMT590. + +<p><i>Amardeep says:</i> +I found a board with the Motorola MCS3201FN and it doesn't do FM. The +data sheet contains much contradictory information. Verbiage only declares +compatibility with IBM system 34 double density. But it also says the MFM +bit is (1 = MFM, 0 = FM) and selection tables show various FM data rates and +sector sizes. The electrical characteristics show only double density +ratings. +<i>Don says:</i> +The two examples that I have been exposed to +suggest that it does not support FM. + +<h4>Will support single density (FM)</h4> +<ul> +<li>NS PC87306 Super I/O +<li>NS PC87307/PC97307 Super I/O +<li>SMC FDC37C65 +<li>SMC FDC37C78 +<li>Intel 82077AA +<li>Intel 82077SL +<li>NS 8477 +<li>Goldstar Prime 2c or 3b +</ul> + +<p>The above NS and SMC parts are completely +stand alone with on board filters, write precomp generators, and data +separators. They should work with FM in any board implementation, +unless something specific is done to prevent it (not likely). This is +per the National and SMSC (new name for SMC semiconductor) data +sheets. Amardeep tested the NS PC87306 and SMC FDC37C65 using Jeff +Vavasour's Model 4 emulator and Tim Mann's xtrs 2.8 under Linux. They +both read and write FM with no problems. It is important to verify +the part number on the chip itself. Many of the newer NS parts +will identify themselves to software as PC87306, but may not +support single density. + +<p>Tim has a machine that uses the NS PC97307, and FM works just fine +on it. Tim used a 360 RPM drive, so 300 RPM drives should work with +this chip too. The PC87307/PC97307 data sheet is not specific about +whether FM is supported. Note that some software may incorrectly +identify these parts as PC87306. + +<p>The Intel 82077AA and 82077SL data sheet clearly states these parts +support FM. Again, verify the part number on the chip. Newer Super +I/O parts like Winbond W83877F or SMC FDC37C665IR may identify +themselves to software as 82077's but may have different characteristics. + +<p>The NS 8477 data sheet indicates that it does support FM (it is +functionally and pin for pin compatible with the Intel 82077). + +<p>A sewing machine/embroidery website +mentioned that "Goldstar Prime 2c or 3b chipset" controller cards can +be used to read single density embroidery diskettes. The URL is +<a href="http://www.wilcom.com.au/stestdsk.htm" +>http://www.wilcom.com.au/stestdsk.htm</a>. + +<h4>Implementation dependent</h4> +<ul> +<li>NS 8473 +<li>NEC 765 +<li>Intel 8272 +</ul> + +<p>This category is meant for older chips that require external +components as part of the data separation logic (or that require +external components if FM is to be supported). Thus they may +or may not support FM depending on the implementation. + +<p>The 1988 data sheet for the NS 8473 states on page 8-32, "While the +controller and data separator support both FM and MFM encoding, the +filter switch circuitry only supports the IBM standard MFM data rates. +To provide both FM and MFM filters external logic may be necessary." +<i>Don says:</i> I have DTK FDC cards with the 8473 and read Osborne 1 +disks with them just prior to writing this. <i>Amardeep says:</i> I +have to recant my original statement that none of my 8473 boards +worked. All three of them do work (read/write/format) at this time. +Must have been an error on my part. + +<p>I believe the 765 was the chip in the original IBM PC, as discussed +above. <i>Amardeep says:</i> Intel 8272 is a NEC 765 clone and +therefore dependent on implementation. + +<h4>Uncertain</h4> +<ul> +<li>SMC FDC37C665IR +<li>SMC FDC37C665GT/FDC37C666GT +<li>Winbond W83877F, 977TF, 83977EF, or other Winbond parts +<li>UMC 8397 +<li>UMC 8398 +<li>UMC UM82C862F or other UMC Super I/O chips +<li>WD 37C65 +</ul> + +<p>Available information on these chips is contradictory. Perhaps +some individual chips of the same part number work with FM and some +don't, perhaps they have bugs that affect some software drivers and +not others, or perhaps there is a 300 RPM vs. 360 RPM problem in some +cases. More testing may be needed. + +<p>The FDC37C665GT and FDC37C665IR have very similar data sheets, and +neither mentions that FM is not supported. However, Pete has an +FDC37C665IR in one of his machines, and FM works on it; while Tim has +an SMC FDC37C665GT in one of his machines, and its FM support does not +work---it can neither read FM nor format FM disks that can be read by +other systems. Tim was using a 360 RPM drive, and Pete did not report +what kind of drive he was using, so it's possible that this was the +issue. + +<p>Amardeep says that the Winbond chips have never worked in FM on any +adapter or motherboard he's ever encountered them on; no idea if it's +the chip or the implementation. Pete says that on his ASUS board, the +Winbond W83877F actually will read and write FM but will not format +FM. Nick Andrew says that the Winbond 83977EF could only read some +sectors when he tried it with xtrs. Steve Tate said that a W83877AF +worked fine for him using 22disk. + +<p><i>Tony says:</i> The data sheet claims the UMC 8398 will do FM or +MFM. In my experience it will correctly handle MFM disks (with both +standard and my own software). When you try FM, it <i>almost</i> +works. It just mangles the last byte in the sector. This is +(apparently) a known problem with this chip. <i>Allison says:</i> +The last byte mashed in the UMC is also common to most 765s and is related +to DMA read/write timing such that if you delay the DMA request by about +1-3uS (several FDD bit times) in FM mode it should work fine. +<i>Amardeep says:</i> The UMC 8398's data sheet says it +does support FM without any external components. Also, the 8397 could be +listed with it. It was the predecessor without high density drive support +for XT applications. Its data sheet also says FM support is provided. +Since Tony's and my testing shows FM tends to fail, and Allison believes it +is DMA related, "uncertain" may be the best category for them. + +<p><i>Amardeep says:</i> UMC did make some Super I/O chips (UM82C862F) +but I couldn't find data sheets for them. I have two IDE/FDC/IO +paddle boards with that chip and neither handles FM. <i>Allison +says:</i> I have used UMC SuperIO chips to do FM with ease using the +internal data separator. + +<p><i>Don says:</i> I have the WD 37C65 in the WD FOX card and +it will also read/write FM. <i>Amardeep says:</i> The only information +I have on the WD 37C65 is the Always IN2000 card I have with that +chip cannot read or write FM. The data +sheet shows there is really no external circuitry associated with data +separator or filters. Yet we have seen examples that pass and fail, so it +might be a revision thing or an untested feature, or DMA mangling or... + +<hr> <h3><a name="[16]" +>[16] What PC add-on cards can read single density (FM) and + other unusual formats? +</a></h3> + +<p>Several different types of add-on floppy controller cards +are available for the PC that will let you read floppy formats that +your built-in controller may not be able to handle, such as single +density (FM). + +<p>Sometimes an add-on floppy card will have a 765-compatible floppy +controller that supports FM. The Adaptec AHA1542CF SCSI hard disk +controller includes a floppy disk controller on the same card that +supports FM and works with both 300 RPM and 360 RPM drives; so do some +other Adaptec cards. This card is easy to use; you just plug it into +any spare ISA slot and disable your motherboard FDC. + +<p>The Catweasel universal floppy disk controller (see <a +href="http://www.jschoenfeld.com/" >http://www.jschoenfeld.com/</a>) +uses custom hardware that +can be programmed to handle just about any format. The software that +comes with the Catweasel can read Amiga, Apple II, and a bunch of +other obscure old formats. I've written a program for the Catweasel +that can copy any disk written by a TRS-80 to the DMK image format +(see topic <a href="#[5]">[5]</a>, including single density and +"copy-protected" disks. It supports both 300 RPM and 360 RPM drives. +The program is now available on the Web at <a +href="http://tim-mann.org/catweasel.html" +>http://tim-mann.org/catweasel.html</a>. It runs on Linux, +MS-DOS, and Windows 95; probably also Windows 98 and Windows ME. It +is untested on other versions of Windows, but probably will not run on +versions that keep tighter control over the hardware such as NT, 2000, +and XP; however, you can use it by booting off an MS-DOS floppy. +Catweasel cards were in short supply for a while, but as of July 2000 +they should be available for purchase again. + +<p>I've heard people mention the +MicroSolutions CompatiCard, but the +<a href="http://www.faqs.org/faqs/CPM-faq/" +>CP/M FAQ</a> says that it is a +discontinued product, so you'd have to find a used one somewhere. +I don't know what chip it uses. + +<p>The <a href="http://retro.icequake.net/dob/" >Central Point Copy II +PC Option Board</a> uses a custom chip and can copy many kinds of +disk, including FM, MFM, GCR, and even disks that used the "weak +bits" method of copy protection. This is also a discontinued product. +I had one of these on loan for a while and read the documentation, but +never found time to install it in a machine and try it. + +<p>I've heard that add-on floppy controller cards for the PC that are +specifically intended for disk duplication or for converting disks +from other kinds of machines often use Western Digital 17xx chips or +custom hardware that is more versatile than standard PC controllers. +I don't know specific model names or where to get these cards. + +<hr><h3><a name="[17]"> +[17] How can I add lowercase to a TRS-80 Model I? +</a></h3> + +<p>Displaying lowercase letters on a TRS-80 Model I requires both a +hardware modification and a software driver. If you aren't sure +whether you have the hardware modification, go into Basic and type +"POKE 15840,98". If you have lowercase, you will see a lowercase "b" +in the middle of the screen; if not, you will see a quotation mark. +If you need the hardware modification, the next section describes how +to install it; if not, +<a href="#lcdrivers">skip down</a> to the section about software +drivers. + +<h4>Lowercase hardware modification</h4> + +<p>A stock Model I has only 7-bit wide video memory. This is enough +for 6-bit, uppercase-only ASCII and the TRS-80's 6-bit graphics +characters, but not for lowercase. In a stock machine, the missing +bit6 is synthesized as !bit7 & !bit5. You can add a true 8th bit +using the following instructions. + +<p>You will need a low-power soldering iron, thin rosin-core solder, thin +insulated copper wire (such as wire-wrap wire), one 2102 static memory +chip (1K x 1 bit) and preferably a new character generator ROM. +The character generator replacement is needed to make the modified machine +compatible with the Level II Basic ROM's display driver and to give it true +descenders on lowercase letters. If you don't have a new character generator, +you will need to install an SPDT switch to turn off the mod when using +Level II Basic or other software that doesn't have a lowercase driver, +and your lowercase g, j, p, q, and y (and maybe a) will be shifted up +a couple of pixels from the baseline. + +<p><i><strong>New:</strong></i> +M.A.D. Software is advertising Model I lowercase +modification assemblies on their +<a href="http://madsoft.lonestar.org/garage/">Garage Sale page</a>! +These should include the 2102 and the character generator ROM, but +check with M.A.D. Software before ordering to be sure. + +<p>Turn your TRS-80 keyboard unit face down on a cloth, and remove the six +bottom screws, being careful to note which went where. Now turn it face +up and lift off the cover. Lift up the keyboard, being careful not to +pull the ribbon cable at the left front loose. Remove the plastic spacers +between the two boards, and lift out the boards, setting them down with +the component side of the logic board up. + +<p>Find Z45 in the lower left corner of the board. The new 2102 will be +mounted piggyback over this one. Bend pins 11 and 12 of the new 2102 +straight out, and set it over Z45. Solder (quickly, with low heat) each +pin of the new 2102, except 11 and 12, to the corresponding one on Z45. + +<p>Find Z30. From its left side run three traces, a narrow one between +two wide ones. Cut through the narrow one with a sharp knife, being +sure to break the connection completely without damaging other traces. +(This trace connects Z30 pin 13 to Z60 pin 4.) + +<p><i>If you don't have a replacement character generator:</i> Find a +mounting place for the SPDT switch where you will be able to get to it +after the case is reassembled. Run a wire from pin 11 of the new chip +to Z60 pin 5. Run a second wire from Z60 pin 4 to the common terminal +of the switch. Run a third wire from another terminal of the switch to +Z30 pin 13. Run a fourth wire from the remaining terminal of the +switch to the new chip's pin 12. One switch position will now give you +uppercase only but will work with Level II Basic; the other will give +you lowercase in software that has a lowercase driver and meaningless +symbols in software that doesn't. + +<p><i>If you do have a replacement character generator:</i> Run a wire +from pin 11 of the new chip to Z60 pin 5. Run a second wire from pin +12 of the new chip to Z60 pin 4. Remove the old character generator +ROM chip (Z29) and replace it with the new one. I think Z29 was +socketed, but if it isn't, you will have to very carefully desolder it +without overheating the PC board and making the traces lift, and +preferably without overheating the old chip in case you need to use it +again. I suggest installing a socket for the new chip. + +<p>Reverse the disassembly procedure to put your machine back together. If +you kept the old CG ROM and installed a switch, try both switch positions +to see what they do. If anything doesn't work, go back and carefully +recheck your wiring. + +<h4><a name="lcdrivers">Lowercase software drivers</a></h4> + +<p>The display driver in the Model I Level II Basic ROM forces everything to +upper case. In fact, it actually writes ASCII codes between 0x00 +and 0x1f into the video RAM and expects them to display as uppercase +letters. That's why you get meaningless symbols if you don't replace +the character generator: the standard character generator has those +symbols in positions 0x00 to 0x1f, but you can't see them until you +add the 8th bit of video memory. + +<p>TRSDOS uses the ROM driver, but alternative operating +systems like LDOS and Newdos include a lowercase driver, as do +many other programs. Usually these programs will detect and use +lowercase automatically if it is present. + +<p>It is possible to add a lowercase driver to TRSDOS or even to +cassette-based Level II Basic. In the future I'll probably add +a listing of such a driver here. + +<hr> +<H3><A NAME="[18]"> + [18] My Model 4 or 4P has video problems in Model 4 mode, but + is fine in Model III mode. How can I fix it? +</a></h3> + +This answer is based on material contributed by David Gish +(gish@gomemphis.com) and others. + +<p>The model 4/4P uses two different methods for generating horizontal +sync pulses for the monitor, depending on whether it's in 64 character +mode (Model III) or 80-character mode (Model 4). In 64-char mode, +horizontal sync is derived from the master clock, which is regulated +by a crystal and thus very stable. However, in 80-char mode a +Phase-Locked Loop circuit (PLL) is used to generate the signal, and it +drifts out of calibration over time. This can result in display +wrap-around or a total loss of sync. There is a trimmer capacitor that +can be adjusted to fix it. + +<p>The biggest problem in making the adjustment is getting to it with +the power turned on so that you can see what you're doing. The trimmer +cap is on the motherboard, with no access from outside the case. On +the Model 4, it's near the top at the back, but the case and a metal +shield are in the way. On the Model 4P, it's near the front of the +CRT, but just far enough under it that you can't get to it with a pot +tweaker. + +<p><i>If some of the terms below leave you behind or the procedure sounds +scary, you should definitely not tackle this yourself -- take it to a +friend who's a hardware techie. Warning: whenever you have the case +open, be careful what you touch, especially with metal objects. +You can get a shock even if power is off, and if power is on, a metal +object touching the wrong two contacts could easily short out the power +supply and fry it.</i> + +<h4>Model 4</h4> + +<p>1. Unplug all cables from the computer. Position the computer on its +back panel to provide access to the case bottom. Remove the ten +screws from the case bottom, noting carefully which went where for +later reassembly. + +<p>2. Position the computer upright and remove the screw and washer +from the top of the back panel. + +<p>3. Position the computer upright with the video screen towards +you. <i><strong>Very carefully</strong></i> remove the case top, +lifting straight up, looking into the case through the vent holes and +the disk bay openings to be certain that you do not catch +the neck (back end) of the picture tube on anything. It is all too +easy to break the picture tube, a very expensive mistake. Once the +tube is clear, rotate the case top 90 degrees counterclockwise +and set it down to the left of the base, being careful not to +overstretch the connecting cables. + +<p>4. Remove the internal metal shields as needed to gain access to +the main circuit board. + +<p>5. Turn the machine on and boot it into Model III (64-column) mode. +It's adequate to go into cassette Basic by holding down the Break key +and pressing the orange reset button. Type enough commands to fill +the screen with text. + +<p>6. Adjust the monitor's horizontal sync back and forth until the picture +breaks up in both directions, then set the adjustment to the middle of +this range. This completes the Model III mode adjustment. + +<p>7. Insert a TRSDOS-6.x disk and boot the system to place it in 80-column +mode. Type the date and then do a DIR to fill the screen edge-to-edge (if +the screen's unreadable, you'll have to type blind). + +<p>8. Find the trimmer cap. Early (non-gate-array) versions may not +have this cap; it does not appear in the Model 4 Technical Reference +Manual, 1983 edition. Hopefully this video problem does not occur on +those machines. On gate array machines, it should be approximately +3 inches from the left of the main circuit board when viewed from the +back, and should be labelled C210. + +<p>9. Adjust the trimmer. You'll need a small pot tweaker, preferably +a non-metallic one. You shouldn't have to adjust it much; it's very +sensitive. Turn the brightness up so you can see the whole raster +pattern and set the trimmer so that the image is stable and centered +in the pattern, with no bent or warped edges. + +<p>10. Turn the power off and unplug the machine. + +<p>11. Reassemble the machine -- you did pay attention to how it came +apart, didn't you? Again be very careful not to damage the picture +tube. + +<h4>Model 4P</h4> + +<p>1. Remove the case and front bezel. The main case is held on by screws +near the front and two large ones under the handle. The front bezel is +held on by several screws inside the case. + +<p>2. Remove the top of the monitor enclosure. + +<p>3. Turn the machine on and boot it into Model III (64-column) mode, +or just reboot it with no disk and wait for the multi-lingual "insert +disk" screen to appear. + +<p>4. Adjust the monitor's horizontal sync back and forth until the picture +breaks up in both directions, then set the adjustment to the middle of +this range. The picture should centered and clean. Replace the top of the +enclosure. + +<p>The PLL adjustment must be done with power on while observing the +screen, since it is very sensitive. This means that the cables all +need to be hooked up at the time. To access the trimmer cap you have +to shift the motherboard forward enough to move the trimmer beyond the +front of the CRT, but still have the critical cables connected. This +is impossible with the factory-supplied disk drive cable connected at +the rear, but the disk drive needs to be connected in order to boot +the system into 80-column mode! + +<p>David Gish came up with the plan below, which works but involves +disconnecting the disk drives from the +motherboard <i>with power on</i>. This is <i>not</i> generally +recommended, except as a last resort. If you do this, follow the +indicated steps carefully to minimize the risk. + +<p>An alternative solution is to replace the factory cable with a +longer one so that you don't have to unplug it. If you do that, you +can change to the longer cable after step 7, then omit steps 11 and +12. + +<p>5. Turn the machine off and lay it on its left side. Keep it on its side +for this entire procedure. + +<p>6. Remove all mounting screws from the motherboard. It should now be +loose, but will not move much due to the cable connections. + +<p>7. Apply electrical tape to the edge connectors at the rear of the +motherboard to prevent shorting these against the frame while moving the +motherboard around. + +<p>7a. If you have a longer disk drive signal cable, replace the +factory cable with it at this point. See topic <a href="#[19]">[19]</a> +for information on making cables. + +<p>8. Carefully examine the motherboard to be sure nothing else is shorting +against the frame and turn the machine on. + +<p>9. Insert a TRSDOS-6.x disk and boot the system to place it in 80-column +mode. Type the date and then do a DIR to fill the screen edge-to-edge (if +the screen's unreadable, you'll have to type blind.) + +<p>10. Remove the TRSDOS disk. + +<p>10a. If you replaced the factory disk drive cable with a longer one +(step 7a), you can now skip the somewhat dangerous steps 11 and 12 and +go directly to step 13. + +<p>11. Carefully unplug the power connectors from both disk drives. This is +to prevent damage during the next step. (Warning: There is an unshielded, +solid-metal fan in this area cooling the monitor enclosure!) + +<p>12. Carefully disconnect the disk drive interface ribbon cable from the +motherboard. This will free the back of the board and give you enough play +to move it forward. + +<p>13. Move the motherboard out and forward, paying close attention to the +rear edge connectors. Now you know the reason for the tape. Watch all +cables while doing this to make sure you're not over-stretching them. + +<p>14. Eventually, you should be able to expose the trimmer cap enough +to make the adjustment. It is probably labeled C231. You'll need a +small pot tweaker, preferably a non-metallic one. You shouldn't +have to adjust it much since, as mentioned above, it's very +sensitive. Turn the brightness up so you can see the whole raster +pattern and set the trimmer so that the image is stable and centered +in the pattern, with no bent or warped edges. (Note: another source +suggests removing the jumper from E1/E2 and putting on in E9/10 while +making the adjustment, then moving it back to E1/E2 when you're done.) + +<p>15. Turn the power off and unplug the machine. + +<p>16. Remove the tape on the motherboard connectors and reassemble the +machine -- you did pay attention to how it came apart, didn't you? +Remember to reconnect the disk drive power and data cables. + +<hr> +<H3><A NAME="[19]"> + [19] I want to add or replace TRS-80 floppy disk drives. + What's going on with the setup and cabling? +</a></h3> + +<p>Cabling a TRS-80 disk drive is a bit tricky. It works differently +from a PC, and there are some differences among the TRS-80 models, +and differences between the Radio Shack way of doing things and other +ways that are sometimes used. I'm sorry there is so much detail here, +but I don't really see how to condense it to a cookbook "just do this" +approach, since there are several things you might want to do with the +information. + +<p>Generally, Radio Shack handled drive select by pulling pins in the +cable connectors. On the Model I, each drive was internally jumpered +to respond on all four different drive selects, the three standard +ones from the Shugart definition (pins 10, 12, 14) and one extra one +that R.S. defined (pin 32, which later was officially defined as side +select for two-sided drives). On the cable, there were four drive +connectors, and each had a different one of those four pins left, with +the other three removed. On the Model III and 4, the internal drives +and external drives were cabled separately, so it was not necessary to +use four different pins for drive select. Instead, the first two +drives are pins 10 and 12 on the internal cable, while the other two +drives are pins 10 and 12 on the external cable. However, the +pin-pulled system is still used. + +<p>An alternative way that many users switched to was to use a plain +cable with all 34 pins intact. Then you have to open up each drive +and make sure that a different drive select is jumpered on each one. +Usually they are jumpers marked DS1, DS2, DS3 (and sometimes also +DS4) or DS0, DS1, DS2 (and sometimes also DS3). Many drives don't +have a jumper for the fourth drive select. Drives that were intended +for Radio Shack Model I systems may have pin 32 hardwired instead of +using a jumper, so beware. + +<p>If you want to use double-sided drives on a TRS-80, you may +have to switch to the pins-intact system in order to bring side +select to every drive. If you have some single-sided drives in the +system, make sure that none of them have pin 32 interally hardwired to +one of the drive selects. TRS-80 Models III, 4, and 4P have +side-select support implemented in the floppy controller and brought +out to pin 32. On the Model I, if you limit yourself to three drives, +you can use the fourth drive select as a side select, as it's +conveniently already wired to the correct pin. LDOS and probably +other Model I operating systems support this. (Let me emphasize that +if any of the drives in a real Model I system is double sided, you can +have at most three drives. Some Model I emulators allow you to have a +fourth drive, but that drive definitely must be single-sided.) + +<p>Pre-made cables and new drives that are commonly available today +usually use the PC system. A PC floppy drive cable has a twist in it +between the two drive connectors (there are always only two). The +twist allows both drives to be jumpered the same way, and allows the +PC to control the motors on the two drives separately. Both drives +are jumpered for drive select on pin 12 (DS2) and motor control on pin +16 (MOT), but the twist reverses the order of pins 10, 12, 14, and 16 +on the first drive, effectively moving its drive select to pin 14 and +motor control to pin 10. A PC-style cable won't work properly with a +TRS-80, because the TRS-80 controller always sends motor control on +pin 16, not pin 10, but it's easy to find ribbon cable and +insulation-displacement (IDC) connectors to make up your own straight +cable if you need one. Or if you only need to connect one drive, you +can plug it into the connector before the twist. Because of this +system, new drives are always jumpered for DS2 by default, but they +can usually be changed. Occasionally you may find a newer drive that +is hardwired for DS2 and has no jumpers; you might be stuck cutting +traces and soldering if this happens to you. + +<p>Also see the article <a +href="http://nemesis.lonestar.org/computers/tandy/hardware/model16_6000/floppyfix.html" +>Utilizing 5.25-inch or 3.5-inch media on your Tandy/Radio Shack computer system</a> +on Frank Durda IV's web site. This is mostly about replacing +8-inch drives with 5.25-inch or 3.5-inch drives, but has some other useful +information too. + +<p>People sometimes also ask about the other internal jumpers in +TRS-80 floppy drives. The exact jumpers that are present vary +depending on the drive manufacturer, but here are some typical +settings. MX or MUX should be open (off); it causes the drive to +ignore drive-select and always respond. HM should be closed (on); it +causes the heads to load when the drive motor turns on. HS should be +open (off); it causes the heads to load only when the drive is +selected (mutually exclusive with HM). + +<hr><H3><A NAME="[20]"> + [20] What about using high density (1.2MB 5.25-inch or 1.44MB 3.25-inch) drives + on a TRS-80? +</a></h3> + +<p>There are two things you might want to do: (1) treat the drive as +single/double density, or (2) use the drive's high density capability +with a TRS-80 floppy controller that was designed for 8-inch drives, if +you have one. + +<p>(1) Both high density and double density 3.5-inch drives spin at 300 +RPM like a double density 5.25 drive, and 3.5-inch double density uses the +same data rate as 5.25-inch double density, so a 3.5-inch drive makes a +compatible replacement for a 5.25-inch drive. The 3.5-inch drive will be +double sided with 80 tracks per side, which most TRS-80 software can +handle. You will have to be sure that the internal jumpers are set +correctly, and that there is no confusion about the Disk Change output +from the drive (not used on a TRS-80), or the High Density signal +(which may have to be wired correctly to make sure the drive uses the +correct write current). If you have a drive you'd like to use but +don't have documentation on its jumpers, search the Web to see if the +drive manufacturer has a Web site that you can get the information +from. For example, <a href="http://www.teac.com/DSPD/catalog.htm#OldFD" +>Teac</a> does. Also be sure to use the appropriate +media; see topic <a href="#[14]">[14]</a>. + +<p>A high-density 5.25-inch drive spins at 360 RPM, not 300 RPM, so it +can't be used directly as a replacement for a 300 RPM TRS-80 drive. +However, some models of 5.25-inch drive have dual-speed motors and can be +jumpered to run at 300 RPM when in double density mode. For example, +the common <a href="http://www.teac.com/DSPD/catalog.htm#OldFD">Teac +FD55GFR</a> drives can do this. If you have a drive you'd like to use +but don't have documentation on its jumpers, search the Web to see if +the drive manufacturer has a Web site that you can get the information +from. Again you'll have to be careful about cabling the Disk Change +and High Density signals. The manufacturer's documentation for your +drive should be helpful here. + +<p>(2) If your TRS-80 has an 8-inch disk controller, you can try +treating a high-density drive as an 8-inch drive. This should more or +less work, but I haven't tried it and can't give detailed help. You +would have to make an adapter cable from the 50-pin card edge +connector to the 34-pin connector on the drive. The +<a href="http://www.faqs.org/faqs/CPM-faq/">CP/M FAQ</a> provides +some useful information for making such cable (see Q14 and Q16). A +5.25-inch HD drive spins at 360 RPM just like an 8-inch DD drive, uses +the same data rate, and has 80 tracks (vs. 77 for an 8-inch drive), so +it makes a compatible replacement. There could be minor issues +because 8-inch drives spin continuously and load/unload the heads when +active, while 5.25-inch drives always have the heads loaded but are +spun down when not active. + +<p>A 3.5-inch HD drive spins at only 300 RPM, but does use the same data +rate and does have 80 tracks. Some software may tolerate a 3.5-inch HD +drive in place of an 8-inch drive, but only the first 5/6 of each track +will be used. Formatting may write arbitrary garbage to the remaining +1/6; hopefully this will not be anything that will cause confusion +when trying to read the first 5/6, but that can't be guaranteed. + +<p>Also see the article <a +href="http://nemesis.lonestar.org/computers/tandy/hardware/model16_6000/floppyfix.html" +>Utilizing 5.25-inch or 3.5-inch media on your Tandy/Radio Shack computer system</a> +on Frank Durda IV's web site. This is mostly about replacing +8-inch drives with 5.25-inch or 3.5-inch drives. + +<hr><h3><a name="[21]"> + [21] What about using low density (360KB 5.25-inch or 720KB 3.25-inch) + drives on a PC? +</a></h3> + +<p>Generally this should work fine, but there are a few problems to +watch out for: + +<p>Check the cabling. A drive pulled out of an old TRS-80 will be +expecting drive selection to be handled differently from the PC method; +see topic <a href="#[19]">[19]</a>. + +<p>Set the correct drive type in your +BIOS! Both operating systems and TRS-80 emulators need to know the +drive type in order to use the correct read/write data rate. There is +no way to autodetect this information, so software has to believe the +BIOS settings. If they are wrong, reading and writing will fail in +odd ways. + +<p><i>Amardeep S. Chana reports:</i> +There is a problem in Jeff Vavasour's emulator code (both Model 4 +and CoCo II, and their support utilities) that incorrectly operates a 360K DD +drive on a HD capable controller. I think what it does is use 300Kbps +data rate instead of 250Kbps. You can create disks and read/write to +them, but a real TRS-80 can't read them. Disks created on a real +TRS-80 won't read on the PC, either. +Using a 1.2MB drive does not show this problem. Using a 360K drive on +an XT-type controller does not show this problem either. Setting the +CMOS type of the 360KB drive to "720K 3.5-inch" also makes the problem +go away. + +<hr><H3><A NAME="[22]"> + [22] What are some other good on-line references for detailed information + about floppy disks and drives? +</a></h3> + +<ul> +<li><a href="http://www.moria.de/~michael/floppy/" + >The floppy user guide</a>, + by Michael Haardt, Alain Knaff, and David C. Niemi. +<li><a href="http://www.tux.org/pub/knaff/fdutils/Fdutils_toc.html" + >Linux floppy utilities</a>, by Alain Knaff. +<li><a href="http://cma.zdnet.com/book/upgraderepair/ch13/ch13.htm" + >Upgrading & Repairing PCs Eighth Edition</a>, Que Books, chapter 13. +<li><a href="http://pilot.ucdavis.edu/davidk/documentation/trs-tech.htm" + >Western Digital 1771 and 179x data sheets</a> +<li><a href="http://www.intel.com" + >Intel</a> - for 82078, 82077, and other Intel floppy + disk controller data sheets. +<li><a href="http://www.smsc.com" + >Standard Microsystems Corporation</a> - for FDC37xxx, FDC87xxx, and + FDC97xxx data sheets. +<li><a href="http://www.national.com" + >National Semiconductor</a> - for PC87xxx and PC97xxx SuperIO data sheets. +<li><a href="http://pluto.njcc.com/~hjohnson/" + >Herb's Stuff</a> - photocopies of drive manuals, etc. +<li><a +href="http://nemesis.lonestar.org/computers/tandy/hardware/model16_6000/floppyfix.html" +>Utilizing 5.25-inch or 3.5-inch media on your Tandy/Radio Shack computer + system</a>, by Frank Durda IV - largely about replacing +8-inch drives with 5.25-inch or 3.5-inch drives, but has other useful information too. +</ul> + +<hr><h3><a name="[23]"> + [23] How do I determine what PDRIVE settings to use for a + NEWDOS/80 disk? +</a></h3> + +<p>This question comes up a lot, but I'm a complete LDOS bigot with no +NEWDOS/80 experience, so I'm not equipped to answer it. Here is some +information kindly supplied by others: + +<h4>Answer by Nick Andrew</h4> + +<p>Let's say you +have a diskette, no idea whatsoever how it is formatted. + +Notes: +<ul> + <li>This process may only work on NEWDOS/80 diskettes + <li>SD diskettes are usually 10 sectors/track + <li>DD diskettes are usually 18 sectors/track + <li>For double-sided, multiply number of sectors by 2 + <li>DD diskettes usually format track 0 single density, and 1 fewer DD + track + <li>I assume user has an 80tk DSDD drive and it's not drive 3 (which + on a Model I can only be single sided) + <li>When changing PDRIVE settings, remember to add A on the end to + activate it + <li>Quick way to copy PDRIVE settings which is not shown in the online + NEWDOS/80 manual is "PDRIVE 0 2=9" which will copy from #9 into #2 + <li>User is using NEWDOS/80 v2 with ZAP/CMD + <li>Reading sectors on superzap:<br> + "dd"<br> + "2,0" (e.g. drive 2, sector 0)<br> + "+" and "-" to step forward and back, "k" to choose another + sector,<br> + "x" to return to the menu (or you can type "EXIT" while sector + browsing) +</ul> + +<p> +a1. set pdrive to double sided single density 10 sectors/track<br> +a2. use zap read sectors 0 through 5<br> +a3. if sector 5 fails, you have a double-density diskette, track 0 SD, +go to b1.<br> +a4. read sectors 6 through 10.<br> +a5. if sector 10 fails, you have a single-sided single-density +diskette. go to c1.<br> +a6. if sector 10 is identical to sector 0, you have a side-select +problem (on a Model I, drive 3 can be single-sided only)<br> +a7. read sectors 11 through 20.<br> +a8. if sector 20 fails, you have a 40 track diskette.<br> +a9. look for the directory track. Look at sector 0 byte 2. Also try +disk sectors 170, 340, 400, 800 looking for the 'P' marker on the sector. + +<p> +b1. set pdrive to DSDD 18 sectors/track<br> +b2. read sectors 0 through 18.<br> +b3. if sector 18 fails, you have a single-sided diskette.<br> +b4. read sectors 19 through 36.<br> +b5. if sector 36 fails, you have a 40 track diskette.<br> +b6. look for the directory track. Look at sector 0 byte 2. Also try +disk sectors 170, 340, 400, 612, 720, 800, 1440 looking for the 'P' +marker on the sector. + +<p> +c1. set pdrive to SSSD 10 sectors/track<br> +c2. read sectors 0 through 10.<br> +c3. if sector 10 fails, you have a 40-track diskette.<br> +c4. look for the directory track. Look at sector 0 byte 2. Also try +disk sectors 170, 400 looking for the 'P' marker on the sector. + +<h4>Answer by Phil Ereaut</h4> + +<p>In Newdos the mysterious Pdrives are just information for each drive, +such as, No. of tracks, Single or double density, Single or Double +sided, and a few other parameters needed by the DOS to interface with +that that disk on that drive. + +<p>The pdrive information can be displayed by the command "Pdrive 0". +Unfortunately, this display does not really mean much to anyone who +has not read and understood the manual. + +<p>The first line of the display may be: + +<pre> +0* TI = A, TD = E, TC = 40, SPT = 18, TSR = 00, GPL = 2, DDSL = 17, DDGA = 2 +</pre> + +<p>This would be a Drive 0, 40 Track, 5 Inch, Single sided, Double +Density disk. + +<p>Generally, the settings for standard type disks are much the same, but +a few people along the way, used many and varied settings for their +GPL, DDSl, etc, which can makes it difficult to read, if you get one +of these disks. + +<p>A Newdos Pdrive table is kept on each disk at, Track 0, Sector 2. +ONLY the table on the SYSTEM disk is used for the drive settings. It +has 10 rows of 16 bytes each, from 00 - 9F hex. Each row is the Pdrive +values 0 to 9 as shown when a "Pdrive 0" command is done. These are +the permanent Pdrive parameters, kept on the SYSTEM disk. + +<p>The number of these actually used is dependant on the number of +drives in use on the system, and are termed active drive slots. The +others are spares, which can be copied to the active drive slots to +allow different type of disks to be used in those drives. +This is done by using the Pdrive command. Example: + +<pre> +pdrive 0,1=6,A +</pre> + +<p>This command moves the values stored in slot 6 to Slot 1. The ,A +causes the change to be made in memory as well as to disk. +If ,A is not used, the change is made only on disk and thus does +not take effect until the next time you reboot. +[Note: information about ,A corrected by Robert Kircher. Thanks.] + +<p>New single Pdrive parameters also can be input, and saved in the +table. Example: + +<pre> +pdrive 0,1,TD=G,DDSL=20 +</pre> + +<p>This command changes the parameters in slot 1 on disk only. +Adding the ,A at the end of the command would also make the change in memory. + +<p>A Pdrive table is on every disk, but it is only the table on the +SYSTEM disk that is used by the System. One use for this table on a +NON SYSTEM disk can be to determine the Pdrive's of this particular +disk. Usually, on a non system disk, the top Pdrive shown is the +Pdrive settings for that disk. (Even though it is not used by the +System for that disk) This allows us to read these settings with a +machine language program, and display the settings of an unknown disk. + +<p>The following contains information about the parameters, and where +they are obtained from. It is not necessary to know ALL of this to +use Pdrives. A general understanding of the parameters shown in the +displayed Pdrive table, and use of some the tables below to interpret +the letters, etc, such as, TI = A is all that is required. Some of +the settings are as shown in the byte; others use bit mapping of the +byte to store the values. Bytes bit mapped are: 02, 07, 0D and 0E, 0F + +<p>The table is set up as shown for row 0 (Shown in Hex): + +<pre> +00 01 02 03 04 05 06 07 08 09 0a 0b 0c 0d 0e 0f +DDSL Lumps * TC SPT GPL * DDSL DDGA TSR - TI - TD +11 48 04 28 12 02 00 01 11 02 00 00 00 01 00 04 +</pre> + +<p>This would be shown in the displayed pdrive table using "Pdrive 0" as +follows. (Values are displayed in decimal.) + +<pre> +0* TI = A, TD = E, TC = 40, SPT = 18, TSR = 00, GPL = 2, DDSL = 17, DDGA = 2 +</pre> + +<p>This would be a 40 Track, 5 Inch, Single sided, Double Density disk. + +<pre> +DDSL = Disk Directory starting lump +Lumps = Total lumps on disk +TC = Track Count: No of tracks on disk +SPT = Sectors per Track +GPL = Granules per Lump +DDGA = Disk Directory Granule Allocation: No of Granules used by the Directory +TSR = Track step rate: Speed of stepping between tracks +TI = Shows interface type, and other required parameters. +TD = Shows Disk size, Density, No of sides, SPT + +Byte 02 (TI & Tsr) +Bit 0 = TSR +Bit 1 = TSR +Bit 2 = A or E (Bits 2&4) or B (Bits 2&3) +Bit 3 = D or B (Bits 2&3) +Bit 4 = C or E (Bits 2&4) +Bit 5 = M +Bit 6 = K +Bit 7 = H + +Byte 07 +Bit 0 = 8 Inch Disk +Bit 1 = Double Sided +Bit 2 = +Bit 3 = I (Lowest track sector is 1) +Bit 4 = +Bit 5 = L (Two steps between tracks) +Bit 6 = K & J (Track 0 Opposite Density) +Bit 7 = Double Density + +Bytes 0D & 0E (TI) +Byte 0D Byte 0E +Bit: 7 6 5 4 3 2 1 0 7 6 5 4 3 2 1 0 + H I E D C B A M L K J I +A = Standard Interface +B = Omnikron +C = Percom Doubler +D = Apparat Disk Controller +E = LNW type +H = 8 Inch drives only. Head settle to be done +I = Lowest sector on Track is 1 (Model3 Trsdos)(Set by flag M) +J = Track No's start from 1 (Is set by K) +K = Track 0 formatted in opposite density to other tracks (Flag J is + set by flag K) +L = Two steps between tracks. Allows 40 Track disks to be read on 80 + Track drive +M = Standard Trsdos Model 3 (Flag M sets flag I) + +Byte 0F (TD Parameter) +Bit 0 = A : 5 inch Single Density Single Sided 10 Secs per Track +Bit 1 = B : 8 inch Single Density Single Sided 17 Secs per Track +Bit 2 = C : 5 inch Single Density Double Sided 20 Secs per Track +Bit 3 = D : 8 inch Single Density Double Sided 34 Secs per Track +Bit 4 = E : 5 inch Double Density Single Sided 18 Secs per Track +Bit 5 = F : 8 inch Double Density Single Sided 26 Secs per Track +Bit 6 = G : 5 inch Double Density Double Sided 36 Secs per Track +Bit 7 = H : 8 inch Double Density Double Sided 52 Secs per Track +(Note that NEWDOS uses the term "track" to mean "cylinder" -- that is, +for double-sided diskettes, NEWDOS counts sectors on both sides of the +disk as part of the same "track".) +</pre> + +<p>Normally the disk is mapped in Tracks, Sectors, and granules. Newdos +uses a different method of disk mapping, using Lumps, in place of +Tracks. These lumps can overlap tracks, starting on one track and +ending on the next track. This can be confusing (only to us; the DOS +knows what it's doing), particularly with the directory, which starts +on a particular lump, not on a particular track. + +<p>In the example shown above: Sectors per Granule = 5 (Standard for +Newdos): Gpl = 2. Therefore there are 10 sectors per lump. The +Directory starts on lump 17, (DDSL = 17). Therefore the Directory +starts on sector 170. As each track has 18 sectors, the Directory +starts on Track 9 Sector 8. This does not really worry the average +user, as the System does all the work. Only those of us who are silly +enough to play around with this stuff, really care whether it is +tracks, or Lumps, or Doughnuts. + +<h4>For more NEWDOS/80 information</h4> + +<ul> +<li><a href="http://www.kjsl.com/trs80/nd80cmds.html" +>NEWDOS/80 Command Summary</a> + +<li><a href="http://pilot.ucdavis.edu/davidk/documentation/trs-oper.htm" +>TRS-80 Documentation Preservation Pages: Operation Manuals</a> +(includes NEWDOS/80 Model III manual) + +</ul> + +<hr><h3><a name="[24]"> + [24] How do I make a bootable double-density Model I LDOS 5.3.1 + system disk from the single-density master disk set? +</a></h3> + +Here is one procedure that works: + +<ul> +<li>Put the single-density LDOS master disk in drive 0. +<li>Put a blank disk in drive 1. +<li>Boot. +<li>Type <tt>FDUBL (TANDY)</tt> or +<tt>FDUBL (PERCOM)</tt>, depending on whether you have a +Tandy or non-Tandy double density adaptor. If you are doing this +procedure on an emulator rather than a real machine, check which type +of adaptor it is emulating. +<li>Type <tt>FORMAT :1 (SYSTEM)</tt> +<li>Answer the questions that FORMAT asks. +<li>Type <tt>SOLE :1</tt> +<li>Type <tt>BACKUP :0 :1 (SYS,INV)</tt> +<li>Type <tt>SYSTEM (DRIVE=1,SYSGEN)</tt> +</ul> + +<p>The disk in drive 1 is now a bootable, double-density LDOS system disk. +Test it as follows: + +<ul> +<li>Remove the LDOS master disk from drive 0. +<li>Move the new disk from drive 1 to drive 0. +<li>Boot. +</ul> + +<p>At this point you may want to put the remaining LDOS files from the +LDOSXTRA disk onto your new boot disk: + +<ul> +<li>Insert the LDOSXTRA disk in drive 1. +<li>Type <tt>BACKUP :1 :0 (SYS,INV)</tt> +</ul> + +<hr><h3><a name="[25]"> + [25] What about using 8-inch drives on a PC? +</a></h3> + +<p>It's surprisingly easy to use an 8-inch drive on a PC. An 8-inch +drive looks electrically very similar to a 5.25-inch HD (1.2MB) drive: +it spins at 360 RPM, has 77 (vs 80) tracks, and the data rate is the +same. The main difference is that 8-inch drives use an older 50-pin +version of the Shugart bus, so you will need a 34- to 50-pin adapter. +The <a href="http://www.faqs.org/faqs/CPM-faq/" +>CP/M FAQ</a> provides some useful information for making such cables, +but watch out for the difference between the IBM PC "twisted cable" standard +and the original Shugart SA400 34-pin bus. At this writing, Q14 in +the CP/M FAQ gives wiring that is right for the old bus but wrong for +the IBM PC version. See Q16 for the changes that IBM made. +You can also buy a nice pre-made adapter from D-Bit (see +<a href="http://www.dbit.com/fdadap.html" +>http://www.dbit.com/fdadap.html</a>), but I haven't tried these. +There could be minor issues because 8-inch drives spin continuously +and normally load/unload the heads when active, while 5.25-inch drives +always have the heads loaded but are spun down when not active. +However, when I tried this, I didn't experience any problems. + +<p>As with all floppy drives, the BIOS settings are important. +Tell the PC BIOS that your 8-inch drive is a 5.25-inch 1.2MB drive, +and it should be happy. + +<p>You can also plug an 8-inch drive into a Catweasel card (see topic +<a href="#[16]">[16]</a>) using the same type of 34- to 50-pin adapter +discussed above. I have one set up this way and working. + +<hr><h3><a name="[26]"> + [26] How can I read the back of a disk that was written in a + flippy drive? +</a></h3> + +<p>A <i>flippy drive</i> has one head, two write-protect sensors, and +two index-hole sensors. You can put an ordinary floppy disk into it +with either side up and read/write to that side. To access the other +side, you have to remove the disk and turn it over. +This is a similar concept to the "flippy disk", but there the +<i>disk</i> is special: it has two index holes in the jacket and two +write protect notches, so you can put it into an ordinary 1-sided +floppy drive with either side up. + +<p>If you have a disk that was written in a flippy drive, but you +don't have any flippy drives, reading it will be difficult, and +writing to it even more difficult. Technically, the index hole signal +shouldn't be needed in order to read or write an ordinary floppy disk, +only to format it (though the signal may be needed to read or write +certain unusual formats). So if you only need to read/write the disk, +you might expect to be able to put it in an ordinary drive upside down +and have it just work. Unfortunately, this doesn't work on drives and +disk controllers made for modern PCs. Modern drives often have +circuitry in them that refuses to send any data to the controller +unless the drive has seen the index hole go by a few times and can tell +that the motor is up to speed. Also, the controller itself may refuse +to accept data until it has seen some index pulses. + +<p>You also might think of trying to read the back of a flippy using +the second head in a regular 2-sided drive. This doesn't work for two +reasons. First, the disk is spinning the wrong way, so the stream of +clock and data bits comes out in reversed order, and a regular floppy +disk controller can't decode it. It's possible to program a Catweasel +to decode the reversed data, but the back head in a 2-sided drive is +offset inward slightly from the front head, so it cannot be positioned +over the data from the first couple of tracks on the back of a flippy. +When the head is against the track 0 stop, it's reading track 2 or 3; +the lower numbered tracks are unreachable. Because of this problem, my +<a href="catweasel.html">Catweasel Floppy Read/Write Tools</a> don't +attempt to decode data from the back of a flippy, but they do have a +feature that <i>detects</i> if there is reversed data on the back and +prints a message reading "Possibly a flippy disk; check reverse side +too". + +<p>Here are a few ways to read (and possibly write) the back of a +flippy: + +<p>(1) The easiest way is to take a hole punch and carefully punch an +extra index hole (in both sides of the jacket, but <i>not</i> in the +magnetic media!) and an extra write protect notch. The easiest way to +see exactly where the holes should go is to take the magnetic media +out of an extra disk that you don't mind destroying (so that you can +see through the jacket's index hole) and use that as a template. + +<p>(2) If you are good with electronics, you may be able to modify a +drive to generate fake index pulses. See <a +href="http://siliconsonic.de/t/flipside.html" +>http://siliconsonic.de/t/flipside.html</a> for one modification idea. +Although the page about the modification refers to the Catweasel, a +drive modified in this way should work with a standard PC floppy disk +controller too. Note that the fake index pulses don't come at the +same point in the disk's rotation as the real index pulse would. This +should not be a problem unless you are dealing with one of the rare +special formats that depends on index pulse position. + +<p>(3) If you have a Catweasel and you use my <a +href="catweasel.html">Catweasel Floppy Read/Write Tools</a>, the -h0 +flag will let cw2dmk read a disk even if the Catweasel doesn't receive +any index pulses. However, you still need to have a drive that will +send data to the Catweasel even when the drive doesn't see any index +holes. An old, TRS-80 vintage drive should work. A newer model of +drive that will work is the Mitsubishi MF504B or MF504C, if you open +the drive up and remove the jumper marked RD. Currently dmk2cw +doesn't support writing to a disk without using the index hole. + +<hr> +<p>** End of TRS-80 Model I/III/4 FAQ ** + +</BODY></HTML> |