vintage computers in active use

[Jay West]

Chuck wrote... (regarding assembly, not machine language):
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"typically tied to hardware"?  Can anyone cite a case where it was not?
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Absolutely. The Pick Operating System assembly language. They could not
afford a machine when they began development of the OS. So they wrote the
entire OS in a "made up" assembly language that didn't really exist on any
real machine. This got them two benefits - one, didn't have to buy hardware
up front, and two, porting the entire OS to a completely different
platform/architecture was a task typically measured in weeks, not months or
years. In addition, because it was a "mythical" assembly language, it
allowed them to pretend they had hardware instructions that were unusually
well suited to manipulating data structures that were unique to the database
architecture.

The os was available on around 30 different machines, everything from ibm
4331, IBM RT, PDP11, 68000, X86, etc. On all those it was implemented one of
two ways - software implementation or hardware implementation. For the
hardware implementation, a firmware board provided the real time
translation/lookup of "Pick Instructions" to "native instructions". For the
software implementations, the assembly process was more interesting. You'd
program in Pick assembly language, then run the pick assembler (written in
pick assembler of course). This would produce pick "virtual machine" (in the
mythical hardware sense, not todays virtual sense) machine language. Then
you'd run a BASIC program (hardware specific) that would translate the pick
machine language to the native processor's assembly language. Then you'd run
the native (z8000 for example) assembler to create native machine code. That
could then be loaded for execution.

J