In 1992, when the T4400 series was introduced, MS-DOS 5.0 was standard and Windows 3.1 was just getting popular. Both operating systems (if you can call Windows 3.x that) run fine on the T4400. Later versions of DOS are no problem but to enable the special Toshiba features like the PopUp menu (Fn-Esc), the AutoResume function and HardRAM, you will need to get the supplemental MS-DOS 6.x disks from Toshiba.
Windows 3.x works great on the T4400 although you need a special driver to enable AutoResume and if you want to access the PopUp facilities you will need some extra software. See the previous page for information on these.
Windows 95 runs fine on the T4400 but AutoResume and other Toshiba specific features will not work. To get the most out of Windows 95 you will need at least 12 Mb. memory.
If you don't already have a 256-colour driver then that is your only option. You can disable internal video and use an external video card in a DeskStation IV (see below).
There have been various BIOS versions. To find out which BIOS version you have try the BIOSVER.EXE command or use DEBUG:
C:\>DEBUG -DF000:E000 F000:E000 54 34 34 30 30 53 58 20-56 33 2E 32 30 20 20 20 T4400SX V3.20 -QThis shows a V3.20 BIOS.
The BIOS version is important to determine which sizes of harddisks the system will accept. See below.
BIOS version 3.50 was the latest and introduced two performance penalties:
- Probably because Toshiba had complaints from people using third-party memory upgrades which were below specification regarding speed (they should be 70 ns.) they added a wait-state in this BIOS. The result is that all memory to register CPU instructions take 3 instead of 2 clock-cycles; a 30% penalty. For some reason this extra wait-state only occurs when memory is accessed in the first 1 Mb. of memory. So this performance penalty will only be noticeable under MS-DOS.
- The BIOS runs from the 1 Mb. of memory so all BIOS routines run slower due to the added wait-state, mentioned above. Also there are numerous loops in the BIOS disk I/O routines that are triggered by the setting of the port that controls the extra wait-state. As a result Windows 16-bit disk access is around 35% slower with BIOS 3.50 compared to earlier BIOS's. (Enabling 32-bit disk access, to circumvent using the BIOS for I/O, is not endorsed by Toshiba since it is not compatible with WRESUME.386; the driver that enables AutoResume under Windows 3.x)
If you happen to have a version 3.50 BIOS then here you can find a small program that disables the extra wait-state and will speed up your disk I/O under Windows 3.1 with upto 35%.If you have a BIOS version below 3.50 then your system will only accept 2.5" disk drives that are specified in the BIOS. Version 3.50 however sends a command to the harddisk to report its geometry and then the BIOS will adapt itself. As a result it recognizes all possible 2.5" IDE drives.
F000:C7E0 25 C8 FF 05 43 50 32 30-34 34 08 4A 44 2D 45 32 ...CP2044.JD-E2 F000:C7F0 38 35 30 50 05 43 50 32-30 36 34 07 4D 4B 31 31 850P.CP2064.MK11 F000:C800 32 32 46 43 05 43 50 32-30 38 34 08 4A 44 2D 45 22FC.CP2084.JD-E F000:C810 32 30 38 35 4D 07 4D 4B-32 30 32 34 46 43 05 43 2085M.MK2024FC.C F000:C820 50 32 31 32 34 07 4D 4B-32 31 32 34 46 43 BA F7 P2124.MK2124FC..The list of drives in a 3.20 BIOS. (CP=CONNER, JD=JVC, MK=TOSHIBA)
There is one problem though; in 1992 a 200 Mb. harddisk (the maximum that the T4400C was produced with) was state-of-the-art so the logical maximum of 528 Mb. that the disk routines in a PC BIOS could access was not a problem.
It is nowadays. New schemes to work with larger harddisks were invented (LBA mode and Enhanced IDE) but no T4400 BIOS include these so even a BIOS 3.50 will only be able to work with 528 Mb. even if the actual disk has more capacity. To get around this you either will need an adapted BIOS, which some vendors sell together with a large drive, or you will need a software solution like EZ-Drive from MicroHouse or Ontrack's Disk Manager.
Another option for your storage needs would be an external ZIP drive, connected to your parallel port. Also, there are a number of suppliers offering hard disks that connect to the parallel port. Don't count on these being fast performers though; the parallel port is too slow for that.
If you can get a DeskStation IV you can install a large harddisk in it. In that case get an ISA EIDE harddisk controller card that has its own BIOS extension and install both in the DeskStation.
The T4400 series came with a 486SX or 486DX CPU, both at 25 Mhz. Since the space within the computer is limited (the CPU is just below the keyboard) the options of upgrading the CPU are limited. Luckily the CPU itself is in a 169-pin ZIF (Zero Insertion Force) socket so upgrading is not difficult.
To get access to the CPU remove the cover from the Memory Expansion slot below the keyboard and take out the 3 screws at the underside under the keyboard, turn the machine over and gently hold the plastic rim at the front of the machine (in front of the space-bar) with both hands between thumb and pointing finger. Then twist the plastic rim towards you to unlock the plastic tabs that hold it in place. Turn the keyboard over and let it rest against the LCD panel. You will see a metal cage fixed with two small screws. Take these out, remove the cage and the processor is in full view.
To remove the CPU pull the lever at the side of the socket upwards; this will unlock the chip and you can take it out easily. Remember its orientation so that you can fit it in correctly again. Insert the new chip with the same orientation (if it is a 169 pin chip like the 487SX then it can only fit one way) and press the lever backwards until it is horizontal again.
You can upgrade the system without any problem to a 486DX2/50. It will then run noticeable faster and will compare well with a 486DX/33. Forget about a 486DX4 since that chip runs on 3.3V and the OverDrive version of that chip (which uses a voltage converter and runs on 5V) has a fan on top so it won't fit. There are versions of AMD or Cyrix chips available that basically are 486DX4/100 chips (running internally on 100 Mhz. but externally ofcourse at 25 Mhz.) with 16 Kb. cache instead of 8 Kb. PC Mall still offers these (the maker, Gainbery, is out of business) at $69,- which is excellent value.
Again you will notice the difference but do not expect too much. The T4400 will not suddenly be as fast as your average Pentium.
A clock oscillator chip (labelled X2) is soldered to the backside of the motherboard. The generated 25 MHz. clock drives the T4400's CPU as well as the controller gate array. To exchange the crystal for a 33 MHz. type you have to disassemble the whole machine (email me if you want to know how). Keep in mind that soldering to the thin PCB is not without risks.
Your only option is a 33 MHz. crystal since the controller gate array within the machine (a huge 344 pin chip) can only run at 16, 25 or 33 MHz. There are two tiny jumpers soldered to the motherboard (W2 and W4) that determine this chip's clock. For 33 MHz. operation jumper W2 has to be taken out. If you want to know where the jumpers are send me email.
If you run the system at 33 MHz. you will need BIOS 3.50 since it adds an extra wait-state for memory access. At 33 MHz. memory will not be able to present data in time since probably your memory is 70 ns. or even slower.
When the T4400 was launched, 14K4 was just around the corner. Toshiba used a proprietary modem slot within its notebooks at that time (before PCMCIA), called the 'T-modem slot'. A large number of suppliers offered modems compatible with this slot, amongst them Holmes and Angia. Unfortunately Toshiba stopped using this slot in 1993/1994 just before 28K8 was even mentioned. So there never have been suppliers of faster than 14K4 modems. I believe Angia still offers a Toshiba 14K4 internal modem.
Unfortunately the external DB9 serial port is controlled by an 8250 compatible chip which is too slow for anything higher than 14K4 in a multi-tasking environment like Windows.
Your only solution is an internal ISA bus modem in a DeskStation IV if you want a fast modem. See below for info on the DeskStation IV.
Memory expansion cards offering 4,8 and 16 Mb. are widely available. Do a search on the internet for instance with AltaVista (keywords: T4400, memory) and you will get a lot of links. You can use memory cards designed for the T6400 also but not for any of the other Toshiba's.
Will not fit so it has to be external. The only port that it could connect to is the parallel port. A number of parties supply CD-ROM drives that will work on the parallel port albeit slow. For loading software it is fine but forget about playing video or audio. Also forget about games that need to access the CD-ROM drive a lot.
The internal speaker it worthless for playing quality sound but the 'Microsoft Windows 3.x driver for PC speaker' at least gives some sort of music for instance as the start-up sound.
If you want real music then you will have to go for a box that connects to the parallel board. Do a search on the internet for 'parallel, sound' and you will get some links of suppliers.
That big connector at the back, behind the plastic lid, has 150 signals and can connect to the Toshiba Desk Station IV. Not for sale anymore but you might be able to find one second-hand. I heard about someone who paid $40,- for it. The DeskStation IV turns the T4400 into a desktop with two full-size 16-bit ISA slots. It supplies the T4400 with power, charges the battery and will pass on all the other ports. A monitor will sit on top and a keyboard in the front connected to the PS/2 keyboard connector. The DeskStation has one bay for a 5.25" device like a CD-ROM player. If you want sound and a CD-ROM player, the DeskStation IV is your best option.
None. I once noticed a supplier who offered a PC-Card cage that connected to the parallel port. Useless for anything else than a modem. There also are available ISA to PCMCIA interface cards that come with a 5.25" card bay that will fit the DeskStation IV.
An external PS/2 mouse works fine. I use a LogiTech Trackman Portable that clips onto the keyboard. Also Microsoft sold a BallPoint Mouse that might be available. It came with a clamp for the keyboard's side that stayed there even if you unclipped the mouse.
The mouse's power supply comes from the T4400 and has a small internal fuse. It is easily blown when you (dis)connect your favourite rodent with the system turned on. Don't do it. Exchanging the fuse is an awful lot of work.