IBM 5322 WAS : Did Dr. Marc Dean Design the IBM PC or was it Lewis Eggebrecht

Guy Sotomayor ggs at
Fri Feb 6 16:17:44 CST 2015

> On Feb 6, 2015, at 2:15 PM, Ali <cctalk at> wrote:
>> I knew Marc from the System/23 Datamaster project (which I also worked
>> on).  I was still working on some aspects of System/23 when the PC was
>> born.  
> Guy,
> That is pretty cool. So now I know if you don't mind I am going to pick your
> brain a bit: Were there two revisions of the 5322? 
> I ask because I have two 5322s and while very similar they differ in at
> least two areas: The older model seems to have a linear PSU and socketted
> chips vs. the newer one with switching PSU and soldered in chips. Just
> wondering. Thanks.

Yea, there were lots of under the radar changes especially early on as things got
figured out.  The original, original PC had 16KB soldered down and then the next
48KB was in sockets.  I think once they figured out that most folks needed more
RAM, they just populated 64KB and did away with the sockets.


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