12 Oct
2005
12 Oct
'05
8:56 a.m.
Right. Those aspects of typical pc hardware that had
been integrated on the chip. Seemingly though, the
Tandy 2000 ignored at least some of the extra
facilities of the 80186 and simply utilized it as a
fast 8086. That board has one of the highest chip
counts I've ever seen. But it's also true that video
I am not sure what you consider to be a high chip count. These days, 20
chips would probably be 'high'. In classic computing, 100-200 ICs is
fairly common, I am sure I've seen boards with more than that.
and much else was integrated.
I opened up a color IBM terminal years ago, mainly
because I wanted to see if the monitor could be
utilized as a vga (apparently had analog inputs, and
only r,g,b, and sync lines). Phor phun. 3179 is the #
sticking in my head, which might correspond to the
model number. But then again it might not. I never
actually bothered, but upon cursory observation of the
logic board - 8088 based - I was amazed how much "pc
stuph" was present. In other words most of the makings
of a pc/xt motherboard were present as I recall. Of
course there were no provision for disk drives and
whatnot, and may not even have had a bios as we know
it. I'd like to get another one.
This reminds me of an IBM colour teerminal that I rescued about 10 years
ago. I didn't get the monitor (I can't rememebr if it simply wasn't
there, or if it was not going to be practically repairable). The base
unit was a plinth that fitted under the monitor, the keyboard was
somewhat PC-like, but IIRC with a different DIN plug to the PC (maybe the
5 pin 240 degree one).
I seem to rememebr a very useful quick reference card slotted into it. It
gave the pinouts of the connctors (amongst other things). Not just the
comms connector, but also the monitor connector and even the connector
for the ROM cartridge. That gave most of the processor bus signals, of
course. I think the PSU was in the monitor, and powered the logic side of
things via the video cable. I can't remember if the ICs were IBM-labelled
or not, but I seem to rememebr there was enough info on that card to work
out much of it.
Somewhat suprisingly for IBM, it was an ASCII unit.
Someone told me that MINIX didn't deal with the
bios
at all. What about Linux?
Only for booting, I think. The initial bootstrap uses some of the BIOS
routines, but once the kernel has loaded, and the machine is kicked into
'386 mode', the BIOS is ignored totally. I know for a fact that linux has
no problem with hard drives bigger than the BIOS can support (the old
540M limit doesn't matter at all), and having read bits of the source
code for the serial, parallel port, keyboard, etc drives, it's clear they
hit the bare metal. And the floppy driver does too.
-tony