[ih] Intel 4004 vs the IMP

[Timothy J. Salo]

This discussion parallels discussions I had in the 1980s at my
then-employer, which build communications processors for mainframe
computers.

Microprocessors were proliferating and quickly gaining in power.
As has been noted, microprocessors typically lacked the I/O
capabilities, throughput and interrupt structure, of purpose-built
communications processors.

But, the real problem with microprocessors, for those who had existing
communications processors and software, was that the microprocessors
had instruction sets that were incompatible with existing communications
processors.  No mater what the benefits of microprocessors, we had
millions of lines of assembly code that would have been pretty much
impossible to port to a microprocessor.  We never tried to port our
software to a 68000 or any other processor.

I believe that BBN was in a similar position with the IMP software,
although obviously there are people here who are far more aware of
this than am I.  If I recall correctly, and my information was
pretty indirect, BBN was trying to port their IMP software to a 68000.
Was this the Butterfly?

But, processors such as the 68000s provided an excellent platform for
companies that weren't burdened by millions of lines of assembly
language software.  Most notably Cisco.  And, we all know how that
story turned out.

-tjs