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Intro
Welcome to part three of an epic feature on the Toshiba T1000.
Part one details the history of this computer more extensively.
Part two (written first, oddly) shows in-depth the steps required to restore a non-working machine to full health.
Part three is an attempt at a definitive technical run-down.
Toshiba published a datasheet on the T1000. I'm replicating some of it here to make it more searchable, but it does include quite a bit of info I deliberately left out. Please refer to the datasheet itself if you do want to know about shortcut keys, environmental specifications, options and accessories, and technical info like memory map, interrupts and port assignments.
Part one details the history of this computer more extensively.
Part two (written first, oddly) shows in-depth the steps required to restore a non-working machine to full health.
Part three is an attempt at a definitive technical run-down.
Datasheet
Model number: PA7027U (FCC ID# CJ69XAE250) Dimensions: 12.2"W x 2.05"H x 11.0"D
Weight: 6.4 lbs.
Voltage: Computer DC input - 9VDC 1.1A (+ = core; - = shell)
AC adapter - 120VAC (108 - 132V), 60Hz, 15W
Battery: Rechargeable internal NiCD battery pack (1300 mAh)
CPU: 80C88, 4.77 MHz
RAM: 512KB standard (conventional)
(Memory expandable to 1.2MB when optional 768KB LIM-EMS 3.2 / HardRAM card added)
Video RAM: 16KB
Number of keys: 82
Keyboard type: Selectable between PC or 101-key keyboard compatible
Drives: One 720KB 3.5" floppy disk drive
Operating system included: Toshiba MS-DOS 2.11 in 256K ROM
Motherboard
A complete XT clone on one board. Pretty impressive, huh?
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| T1000 Motherboard. Source: Author. |
Display Controller Subsystem
HM6264LFP-15T (IC36, IC37) are 8-bit high speed CMOS static RAM manufactured by Hitachi. Each chip is 8K for a total video RAM of 16K with 150ns response time. This equates to an operating frequency of 6.66MHz.
DC2054P138A (IC31) is Toshiba's gate array for controlling the dot matrix display and external CRT. There is no published datasheet, but technical details for all the proprietary ICs may be found in the T1000 maintenance manual.
TC53257F (IC32) is the character generator ROM.
Chipset
- 82C84 clock generator
- 82C88 bus controller
- 82C53 programmable interval timer
- 82C59 programmable interrupt controller
- memory and I/O address control
- system bus control
- 82C37 DMA control unit
- 8565 real time clock
It also interfaces with the speaker, keyboard (80C50), floppy drive and external bus.
- printer interface
- I/O address decoder
- system RAM controller
- DOS ROM controller
- system support port
IC35 is a microcontroller based on the 80C50 and is utilised as the keyboard controller.
TC8570F (IC11) is the UART chip.
Finally, TC8521P (IC3) is the RTC & CMOS RAM. Although it isn't Y2K compliant, Toshiba have implemented it in a clever way as to make the actual computer compliant. The RAM holds the system configuration
CPU and RAM
OKI's version of Intel's 8088 was originally designed by Harris Semiconductor and is basically an Intel 8088 but fabricated using CMOS manufacturing process. This reduces power consumption compared with the original part while maintaining full software compatibility. It is 16-bit internally, with an 8-bit data bus and can address 1MB of memory. The RAM chips are Toshiba model TC514256PL-12 (IC17-IC20), also CMOS parts. With a 12ns access time, they can operate up to 8MHz. Each chip obviously provides 128KB of memory
Display
At one point, Axonix provided a service to retrofit a backlight to the T1000. This was not a trivial upgrade as it took 5 days, added weight, increased power consumption and worsened the readability of the display without the backlight. It's possible there's a way to do it using more modern technology but I think too much could go wrong for it to be worthwhile. Get yourself a T1000SE if you want a backlit screen.
Floppy Drive
The T1000 comes equipped with a 3.5" floppy drive. This is a double-density, double-sided, double-track drive supporting 720KB disks. These are the specs according to the maintenance manual.Storage Capacity (kilobytes): 1000 (unformatted), 720 (formatted)
Number of Heads: 2
Number of Tracks per Side: 80
Track to Track Access (ms): 6
Head Setting Time (ms): 15
Track Density (tracks/s): 135
Motor Start-up Time (ms): 500
Data Transfer Rate (kilobits/s): 250
Rotational Speed (rpm): 300
Recording Method: MFM
Software
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| TC532000P is a 2Mbit mask ROM and holds the operating system. TC57256AD-20 is the BIOS ROM. |
There are two known versions of the BIOS (I'll dump mine at some point in the future for reference):
026C: v1.10, 29 June 1987
026F: v4.10, 2 May 1988
As mentioned, the T1000 avoided inclusion of an additional floppy drive with Toshiba DOS 2.11 / R2A on mask ROM (If a mask ROM is like a CD-ROM, an EPROM is like a CD-RW). The ROM in my T1000 was created on March 17, 1987 according to the readout from CHKDSK.EXE. It has the volume label IC-DISK ROM and includes the following DOS-related files with the same date stamp as the ROM:
| ANSI.SYS ASSIGN.COM AUTOEXEC.BAT CHAD.COM CHKDSK.COM COMP.EXE CONFIG.SYS DEBUG.COM DISKCOMP.COM DISKCOPY.COM EDLIN.COM FIND.EXE FORMAT.COM GFTABLE.COM |
1902 904 106 6353 6468 8318 160 12146 10011 10329 4389 6331 6240 3243 |
GRAPHICS.COM KBOARD.SYS LABEL.COM MODE.COM MORE.COM NOW.EXE PRINT.COM RECOVER.COM SELECT.EXE SORT.EXE SYS.COM TREE.COM VDISK.SYS |
973 4431 1280 2377 4364 5410 4515 2295 11022 1632 1920 1988 1286 |
The following Toshiba programs are also included, with date stamp June 11, 1987. Based on this, it can be assumed that a T1000 with either BIOS listed above has the same DOS ROM:
| EMM.SYS COMMAND.COM SETUP10.EXE TEST10.EXE | 8691 16598 10224 17648 |
Driver for RAM expansion card Toshiba DOS command interpreter T1000 setup program T1000 diagnostics program |
There is also a folder called KB1000, which has keyboard drivers for Spanish, German, French, UK English, Italian, Danish, Swedish, Netherlands (Dutch) and Slovakian.
Here is a printout of AUTOEXEC.BAT:
echo off
echo
path c:\
NOW
echo
if not exist D:autoexec.bat goto No-IC
D:
autoexec
:No-IC
Config.sys has one line:
Country=001
The ROM effectively simulates a floppy disk in the way that it is organised. John Elliott's T1000 page goes into all the detail you could possibly need to know about the ROM itself so there's no point me replicating it here.
I've seen it alleged that Toshiba offered ROM upgrades for sale to provide a more recent version of DOS than 2.11 for the T1000 but it seems these were never available. Given that DOS 2.x was released for the IBM PC XT originally, it's pretty much the appropriate version for this computer and there would be limited practical advantages to upgrading it if you're using period-correct software. DOS 3.x mainly brought with it enhancements to hard disk partitioning and high density floppy disk support anyway, and these are redundant with the way the T1000 is configured.
You can boot DOS 5.0 via floppy disk, but the ROM will not be recognised. It is also possible to burn yourself a ROM with a different operating system and / or additional software.
Method 1: DISK2ROM
John Elliott actually went to the trouble of writing a program that converts a floppy disk image into a format that can be either burned onto an EPROM or run in an emulator. One issue with this method is that you have to use the version of DOS that came with the T1000. This is because the ROM image has no partition table and versions of DOS after 2.x don't recognise this configuration. It's certainly the simplest way though, and the files can be downloaded using the link above.
Method 2: Manually
Method 3: Use the Hard RAM
KnowledgeBase Archive
minuszerodegrees.net (PDF)
Essentially you can either reconfigure the RAM card as drive C, or boot from floppy and use the RAM as static storage.
That's all I can be bothered to write at the moment. As and when I decide to add more, I will.
Revisions
18 Nov 2018: added information on floppy drive.
12 Feb 2020: formatting changes so it's less broken. PSU info. Replicated some info from the Toshiba's 'datasheet' of the T1000.
12 Feb 2020: formatting changes so it's less broken. PSU info. Replicated some info from the Toshiba's 'datasheet' of the T1000.
6 Aug 2021: added some more useful information from the service manual. Although it would be pointless to reproduce all of it, there are some useful snippets, such as shortcut keys for external display, etc.