(last updated: 10-Feb-2017)
Stock system except that I have replaced the original Intel 8088 CPU chip with a NEC V20 CPU. In theory, the V20 provides a higher level of internal performance.
| Tandy 1000A, NEC V20 CPU @ 4.77MHz, 128KB RAM | |
|---|---|
| ISA8 | Tandy 25-1011 512KB Memory PLUS Expansion board w/ RS-232 Serial port |
| SMC/Western Digital 8003-EP ethernet adapter | |
| Western Digital WD1002-WX1 MFM hard disk controller | |
01-Aug-1985
This unit was purchase at the Tandy Computer Center in Orem, Utah with dual floppy drives, a CM-4 CGA color monitor, and a 512KB memory expansion board that included a piggy-backed RS-232 serial port.
15-Aug-2007
After receiving a triplet of Seagate ST-225 MFM drives via eBay, I rounded up a Western Digital WD1002-WX1 8-bit MFM controller, also from ebay, in a lot sale. Online reading had suggested that this particular controller was usable in the Tandy 1000 computer, and as long as the hardware interrupt is set to 2.
[I can't remember if setting IRQ2 was done via jumpers or a little trace cutting and soldering. Someday I'll take a look and confirm. Also, see notes for Tandy 1000A #2.]
The WX1002-WX1 has the "Super Bios Formatter" that is entered via a debug command:
C:> DEBUG - g=c800:0005
Then follow the prompts.
03-Aug-2014
Since 2007 I have been using this system, on and off, as a little web server(!) running NOS/JNOS/EZNOS. It's been good, but every so often while it is logging activity, for example, I hear the hard drive doing retries, and then eventually continues. This suggests that the drive has a few flaky sectors.
The Tandy version of DOS 3.3 that I'm using doesn't have any particular tools for hard disk maintenance (e.g., SCANDISK and defragger), so I reconstited a floppy with Gazelle's OPTune and started to work with the drive, hoping it could perform a bad block search as well as defrag the drive. Indeed it can do all of these things.
I learned that I have several files that are currently unreadable due to sector errors:
- C:TELNETFTPBIN.EXE (from ftp://ftp.oldskool.org/pub/tvdog/internet/tel2308b.zip) - C:JNOSWWWPKTD11.ZIP (from http://www.crynwr.com/drivers/) - C:JNOS2NOSHELPAX25 (can copy from C:JNOSNOSHELPAX25) - C:BBBSBBBS.EXE (can be restored from BBBS.ZIP)
I also learned that the hard drive's interleave factor is the worst possible! It was formatted with 1:2 factor, but OPTune shows that a 1:4 factor gives a 280% speedup!
So, after a defrag operation terminated early due to sector errors, I figured I'd just go ahead with the optimization to set the new interleave factor which reformats each track in the course of its work. I haven't used OPTune for a very, very long time, and I wasn't prepared with a formatted floppy when it asked for one. I escaped from the dialog, then quit. Sadly, after a reboot, the boot sector seems munched and the system will no longer boot from the hard disk.
After some not-insignificant effort I was able to re-locate and restore the 2-disk Tandy-ized MSDOS 3.3 images to floppies. Fortunately, a boot from the floppy shows that all other hard disk contents are intact. I tried to re-install the boot sector, but alas, SYS /S reports that there is insufficient room on the drive.
So, this leads to a new effort to backup the disk's contents, reformat the HDD, tune it with Optune, then restore the original contents.
--- HDD Backup ---
This task proved harder than I expected. Though this machine can act as an internal and external webserver, it isn't really integrated with my LAN. I had a couple of choices, other than backup to 60(!) floppies: 1) use a serial file transfer tool (e.g., LapLink, WinLink), or, 2) try to run MSCLIENT and get on the local LAN. I don't remember setting up MSCLIENT on this system in the past and I expect that to be quite a chore, so I chose the first route, serial file transfer.
The first issue was digging up a serial cable that would match up with the FEMALE connector on the Tandy side. I ended up using a cable that came along with my Darien PDP-11/23+ which has a female DB-25 on one end and a male DB-25 on the other. The cable is straight through so I had to dig out a gender changer and a 25pin-to-9pin converter for the target PC side of things. I was finally connected, but...
Oh, oh, how hard it is! I'd forgotten how slow even 115Kbps is, and after trying to use a VERY TEMPERMENTAL LapLink (LL.EXE) I decided to use WinLink (WL.EXE). But, I had to use LL to get WL over to the Tandy in the first place! After many false starts, I was finally able to get a good copy of WL over. Whew! And is it a breath of fresh air compared to LL. It actually works reliably.
I moved all the files I could (except the few with sector errors listed previously) to my Unmack IBM Aptiva Pentium 133 system booted to a Win98 DOS prompt.
At this point I made sure that I had a bootable floppy with Tandy-ized MSDOS 3.3 with the DEBUG.COM, FDISK.EXE and FORMAT.COM onboard, and another floppy with WinLink.
--- HDD Re-Format ---
The backup is complete, with a few errors that can be overcome. Nothing significant was unreadable.
Using the built-in formatter on the WD WX1002-WX1 controller I reformatted the drive using an interleave factor of 4:
C:> DEBUG - G=C800:0005 [...] Current interleave is 3, select new interleave or RETURN: 4 Are you dynamically configuring the drive? N Press 'y' to begin format: Y [...] Do you want to format bad tracks? N
With the drive newly formatted, I rebooted to floppy and ran FDISK, creating a primary DOS partition using the entire drive. Then I used FORMAT /S to verify the drive and install the boot stuff. FORMAT found a sector or two that were bad and completed. The results show that there are 10240 bytes unavailable due to bad sectors in a cluster.
Next I fired up WinLink and restore OPTune to the hard disk so that I could really test the format.
In OPTune I used the Verify/Fix Drive option to do BIT 1 (A) test that writes and reads sectors. It found several more sectors that were unusable and marked them, no showing 14336 bytes unavailable.
One thing of interest is that while I could copy FROM the Tandy at 115Kbps, copying TO the Tandy was only successful at 56Kbps. So the restoration will be slower.
--- HDD Restore ---
With the drive reformated with interleave factor of 4, FDISKed and FORMATted, then OPTuned, I used WinLink to restore everything. At 54Kbps it worked just fine, taking about one hour total.
Finally, I restored the handful of files that were unreadable from the drive and I was finished!
Well, mostly. Turns out that one file didn't make it across originally, my START.BAT file in the JNOS dir. I rebuilt it and now all is well.
Copyright © 2006-2025 Jared Blaser. All rights reserved.