HP 2100A vs. 2100S

J. David Bryan jdbryan at acm.org
Tue Jan 9 12:59:12 CST 2007

On 9 Jan 2007 at 12:19, Jay West wrote:

> As a result - it is best to disregard ALL of the above and just consider
> the machines identical. 

Just what I needed to know, thanks.  Much appreciated.

> One exception. There is some disparity between the two (given certain
> date codes... 

This is not uncommon with the 1000 machines either.  For example, regarding 
the F-Series machines being discussed in another thread, machines before 
date code 1920 are missing a fair number of instructions (four-word 
floating-point instructions, double-integer instructions, and a few SIS 
codes).  The manual at the HP Computer Museum I cited in that thread was 
for the earlier machine.  If you have the same manual for the post-1920 
machine, I'd love to scan it.  :-)

Similarly, regarding RTE, M- and E-Series machines with CPU boards prior to 
about date code 1730 required massive hardware upgrades to run RTE-IV or 
later.  CPU board, DMS ROMs, memory controller, memory protect, I/O 
backplane (!), etc. had to be exchanged for newer versions.

So it's quite true that the name on the front of the box isn't the whole 
story as to what's in the box....

                                      -- Dave

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