IBM did not build a PS2 clone. The PS2 was an attempt by IBM to retake the market that they had created with the IBM 5150 and it's successors. Compaq PC "(IBM) PC clones" were setting the new standard. IBM changed most of the connectors for the PS2 series and tried to make the PS2 the IBM in the IBM PC Compatible label. The PS2 line was short lived, but the smaller connectors lived on. This is the origon of PS2 mice & keyboards.

In response to Ted's comments regarding the term EPROM. EPROM actually stands for erasable programmable read-only memory. Its not really like a CD-RW disc, because it has a clear window in the top of the DIP package and has to be erased by exposure to ultra-violet light, not electricity. I think you are referring to an EEPROM, which can be electrically written to and then electrically erased. 

PROM's were another early form of non-volatile memory that were written to by sending a strong write current across PN junctions inside the chip and literally burning them out. Once they were burned the results could never be undone. EPROMs were more economical because they could be exposed to ultra-violet light, erased and then recycled again for another use. Typically an opaque foil label was placed over the chip's small window to prevent accidental erasure in case the chip was left out in the open.

Am I the only one for whom Felsenstein's two slides did not appear?

Thanks for this second article. Will there be a third?

One minor correction. In the third paragraph, the word "electronically" in the phrase, "EPROM (electronically programmable read only memory)" should be replaced with "erasable". Think of an EPROM as a CDRW. A PROM would be analagous to a CDR and following that, a ROM is the same as a silver CD that you would buy in the store - already programmed/burnt (stamped).

Loving this.

Getting all emotional ... found a 360k floppy <sob> ...

;p

Did anyone else notice the problem with this article?

It seems to assume that the personal computer was first invented and developed in North America.

IIRC didn't the United Kingdom have a valid PC market way before the Tandy and IBM PC?

Sinclair, Acorn, Cambridge, etc. all come to mind.


I am using PC here with its original meaning of course and not as a IBM clone of a PS2.



There is (or was?) an interesting little pre-DOS only computer museum in the small town of Annapolis Royal, Nova Scotia, Canada. The gentleman that ran it had some of the very earliest personal computers available.

Personally, I skipped the TS-80 Model 1 and started with TRS-80 Model 3s, Model 4s and Color Computers. Mid-1970s. Plenty of daisy wheel printers too...