====== Toshiba T4800CT ======
Specifications:
CPU....: 80486SL DX4 / 75 MHz
RAM....: 8 MB onboard, extendable to 24 MB using a credit-card size memory chip
Graphic: Western Digital Paradise 90C24 (SVGA), 256 colors, 1 MB
Sound..: Microsoft Sound System (also known as 'WSS')
HDD....: 500 MB IDE
=== BIOS ===
As most portable computers, the T4800CT presents a very limited BIOS. Nonetheless, it might come handy to look into it, and for that, one must know how get into the BIOS in the first place. After a few 'trial and error' attempts, I figured that I have to press the ESC key just after the computer power up, and then I am asked to press F1 to enter into the BIOS setup screen.
=== HDD controller ===
The IDE controller is compatible with CompactFlash cards, which allowed me to replace the original ~500M hard drive by a 4 GB Compact Flash card using a cheap CompactFlash->IDE 2.5" adapter. Note, that the T4800CT doesn't support LBA, hence it will access the disk in legacy CHS mode. This means that if you are going to access this disk from another machine (for example to move some files quickly, or simply to format the disk and install an OS), you have to take care that this other machine accesses the disk via standard CHS mode, too, otherwise the T4800CT won't be able to figure out the data you wrote on it (personally I was getting an error message "partition signature != 55AA" at boot, but your symptoms could be different).
=== Video ===
The graphic card is a plainly compatible with VGA, no worry there. However, should you need to use anything more than VGA under DOS, then a problem will appear: this WD Paradise card has no VESA BIOS, hence no DOS application will be able to use it beyond standard VGA mode. Fear not, a solution exists: use a VESA driver, like the freeware UNIVBE tool, or Western Digital's driver for Paradise cards (I recommend the former, since drivers from WD only provide VESA 1.x emulation). Such a driver will emulate a VESA API, and talk to the graphic card using its proprietary protocols.
Note, that when UniVBE 4.0 autodetects the card, a very nasty graphic effect is appearing - the screen becomes all garbled, and the luminosity increases for a short moment, then, after 2-3s, the effect disappears and everything is fine. For some this might be no big deal, but I really dislike to see such ugly behavior every time the computer boots.
=== Sound ===
The sound appears to be a more or less standard WSS card, although it lacks any FM or MIDI support. This was a chip from Analog Devices, the AD1828, that was installed in the Performance Series T4700, T4800, T4850, and T4900 models. Some DOS software will presumably be able to use it as-is (assuming said software supports WSS, although I couldn't get any to work), and other might benefit from the SB-emulation provided by the WSSXLAT.EXE driver from Microsoft's WSS disk 2.0 (works only when using DOS 6.2 or later, and only if EMM386 is loaded). Usually the WSSXLAT.EXE is configured using a Windows 3.x tool called WSSCNFG.EXE. All this tool does is adding a few lines to the CONFIG.SYS, as seen on the example below:
DEVICE=C:\WINDOWS\HIMEM.SYS
DEVICE=C:\SNDSYS\EMM386.EXE 512 RAM
DEVICE=C:\SNDSYS\WSSXLAT.EXE sbio=220 irq=7 dma=1
The DEVICE=C:\SNDSYS\WSSXLAT.EXE line is the actual Sound Blaster emulation driver. It will not load if the EMM386.EXE line described above is not present. The following parameters are valid:
sbio=<220 or 240> Determines which I/O address the emulator should trap
irq=<7,9,10 or 11> Determines which interrupt the emulator should check
dma=<0,1 or 3> Determines which Direct Memory Access channel the emulator should monitor
wave=<1-9> Controls the volume for digitized sound in the Sound Blaster emulation
line=<1-9> Controls the volume for audio pass-through in the Sound Blaster mode
Known sound bug: The sound device does not work with resume, without reinitializing by the running software. Computer will resume, but sound will not. (this information is gathered from Toshiba's support FAQ)
=== Networking ===
This laptop comes with lots of cool ports (VGA, 2x PS/2, COM, LPT) but unfortunately it lacks an ethernet card, which makes file transfers a little tricky - one has to use either floppies or a serial/parallel connection with software like LapLink. None of these options is comfortable nowadays, so the best is to add a network card on one the PCMCIA slots. Take care to choose your network card wisely, the T4800 provides 16bit PCMCIA slots only, compatible with the PCMCIA standard v2.01, while many PCMCIA network cards require either a 32bit slot, CardBus (which is the same as PCMCIA v5.0) or PCMCIA v2.1.
I tested two of my network cards: a Xircom CE3-100BTX and a double-height Xircom "RealPort" REM56G-100. Both works fine. I found many places saying that I should use the 'cardsoft' software for enabling PCMCIA under DOS, but it isn't true. Both my network cards are handled perfectly using only the packet driver from Xircom (now Intel). I did try the whole cardsoft software, but it proved to be only a nuisance - it takes a whole lot of conventional RAM (over 100K!), while the cards work just fine without it. I think the only added value of cardsoft drivers is to make it possible to hot-plug PCMCIA cards, and use flash memory on PCMCIA. For a network card that never gets out of its PCMCIA socket it's quite useless (but maybe other models of computers and/or network cards need this, no idea).
Below is a list of a few T4800-related files that I fetched from Toshiba servers:
BIN test3.exe - A diagnostic tool for T-Series Toshiba laptops
Release Date: 1991-12-12
Compatible with: T-Series T4700CS, T-Series T4700CT, T-Series T4800CT, T-Series T4850CT, T-Series T4900CT.
BIN tdiags.exe - Another (apparently newer) diagnostic tool from Toshiba.
Release Date: 1994-06-22
Compatible with: Satellite T2100, Satellite T2100CS, Satellite T2100CT, Satellite T2105CS, Satellite T2105CS, Satellite T2105CT, Satellite T2110CS, Satellite T2115CS, Satellite T2130CS, Satellite T2130CT, Satellite T2150CDS, Satellite T2150CDT, Satellite T2155CDS, Satellite Pro 400CDT, Satellite Pro 400CS, Satellite Pro 405CS, Satellite Pro 410CDT, Satellite Pro 415CS, Satellite Pro 420CDS, Satellite Pro 420CDT, Satellite Pro 425CDS, Satellite Pro 425CDT, Satellite Pro 430CDS, Satellite Pro 430CDT, Satellite Pro 435CDS, Satellite Pro 435CDT, T-Series T2400CS, T-Series T2400CT, T-Series T2450CT, T-Series T3400, T-Series T3400CT, T-Series T3600CT, T-Series T4700CT, T-Series T4800CT, T-Series T4850CT, T-Series T4900CT.
BIN 4748v500.exe - Latest BIOS image, version 5.00
Release Date: 1995-08-16
Compatible with: T4700CT, T4700CS, and T4800CT.
BIN t48man.exe - T4800CT user manual in ASCII format
Release Date: 1994-01-01
t48man.pdf - T4800CT specifications sheet
BIN 90c24.exe - Windows 3.1x video drivers
Release Date: 1995-02-22
Compatible with: T1950CT, T1960CT, T3400 series, T3600CT, T4700 Series, T4800CT, T4850CT.
BIN tosh2000.exe - Toshiba Year 2000 CMOS Update version 1.00RC2 for DOS/Win3x/Win95. Provides year 2000 compliance under DOS/Win3x and Win95 for many models produced prior to April 1996.
Release Date: 1998-01-23
Compatible with: Satellite T2100, Satellite T2100CS, Satellite T2100CT, Satellite T2105CS, Satellite T2105CT, Satellite T2110CS, Satellite T2115CS, Satellite T2130CS, Satellite T2130CT, Satellite T2150CDS, Satellite T2150CDT, Satellite T2155CDS, T-Series T1900, T-Series T1910, T-Series T1950, T-Series T1950CS, T-Series T1950CT, T-Series T1960C, T-Series T1960CS, T-Series T2400CS, T-Series T2400CT, T-Series T2450CT, T-Series T3600CT, T-Series T4700CS, T-Series T4700CT, T-Series T4800CT, T-Series T4850CT, T-Series T4900CT.