Altair - A different perspective

From: Jack Peacock <peacock_at_simconv.com>
Date: Wed Aug 26 18:47:31 1998

> >I'd love to see a manual for the chipset and microcode information.
>
> I think the burning question would be: How does one debug somehting
> like this?

For a commercial company, microcode is tested and debugged on software
simulators before the hardware is even completed. Once the architecture
is defined, software is developed in parallel with the hardware to
simulate the components. Microcode is tested on the simulator, much
easier than using a scope and analyzer. Course, the component
descriptions given to the simulator programmers (these are usually
programmers with a good EE background who understand boards at the chip
level) had better be accurate.

And in parallel to that, an emulator is also done for the target
instruction set. This allows systems programmers to develop the initial
assembler, compiler and operating system for the new CPU. That's how a
completely new CPU design, with no backward compatibility, can appear
all at once. By the time the hardware prototype is ready, there is a
complete set of diagnostics and an OS to boot up. In theory that is ...

Tracey Kidder's book, The Soul Of a New Machine, detailed some of that
process when Data General switched from the 16-bit Nova to the 32-bit
Eclipse.
      Jack Peacock
Received on Wed Aug 26 1998 - 18:47:31 BST

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