There's even a fair amount of interesting esoteria
about the first IBM
PCs that should be on-topic. I.e.: The very first boxes from IBM had
painted black power supplies, painted black card-edge plates, and
Not to mention some of the more obscure IBM I/O cards (Profession
Graphics Adapter, Lab I/O, networking, PC/370 processor, etc).
sported one row of 16Kx1 RAM chips soldered in place,
and up to three
more in sockets, if you ordered more than 16K of memory with your
system. Also included was the audio-cassette cable, since the first
Was it? I realise original IBM PCs (5150 machines) have the cassette
port, but I thought you were expected to get the cable from RatShack.
The 5 pin DIN socket has the same pinout as the TRS-80...
PCs (I think up to the 256K motherboards) could be
purchased with no
floppy drives and boot into 'cassette BASIC' in ROM and store and
recall programs from audio cassette, like many other machines of the
era.
ROM BASIC is present in the XT and AT too, but with no cassette
interface. I have sometimes wondered about making an I/O card with a BIOS
extension ROM that intercepts INT 15 (IIRC) and, say, uses a paper tape
punch/reader as storage. I think that would work with the ROM BASIC in
the latter machines.
I doubt if there will be many people posting support
questions about
the dipswitch settings (confusing as hell, they were) for that
generation of hardware to tell the motherboard how much memory was
installed, and where (motherboard versus on the I/O channel).
FWIW, I have the IBM TechRefs for the PC, PC/XT and PC/AT machines.
I also have an all-original IBM-AT box (6 MHz), with
IBM's EGA card in
it, and all IBM hardware throughout. I personally consider it
My AT is much modified, but it still has the IBM Motherboard (with a 486
kludgeboard in the CPU socket...)
I did find a PC/XT system that was 100% IBM. Even has the expansion unit
(containing 2 10Mbyte hard drives...)
-tony