the 2 old original IBM machines

Fred Cisin cisin at
Wed May 20 16:19:32 CDT 2015

On Wed, 20 May 2015, Electronics Plus wrote:
> 8088 computers, one has 2 floppies, 1 has 1 floppy and 1 hdd.
> Both fully tested and functional.  No keyboards now, but there is an
> original IBM mono monitor, and the printer.
> I do NOT want to ship; these will not survive UPS very well.
> We are about 1 hour from San Antonio.
> Make a good offer, take them home.
> Lots of software to go with these.
> Must be gone before Monday.
> I will be at the warehouse all weekend.

By default, the PC (5150) is floppy only.
By default, The XT (5160) has hard^H^H^H FIXED disk  (IBM didn't want to 
imply that an HDD was hard to use)

But, there are exceptions.  HDD could be added to PC, XT could be 
purchased without HDD.

Therefore, the obvious definitive recognizable differences are:
PC has 5 expansion slots; XT has 8.   XT usually came with an async 
(RS232/current loop) board in slot closest to power supply due to slight 
incompatabilities of that slot.

Power supplies are different size (63.5/65 for PC, 130?/135? for XT),
but often swapped.
Some early PC power supplies were black, with a white toggle switch.

PC has a cassette port!  That other connector next to the keyboard 
connector is NOT for a second keyboard.  Around here, IBM did not sell a 
cord for the cassette port, but it was compatible with the Radio-Shack 
model 1 cable.

There are some more subtle differences if you open the case.
The PC had 4 rows of RAM, with one soldered in.  Early was 16K/64K,
later ones were 64K/256K

Do the differences matter?

Grumpy Ol' Fred     		cisin at

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