On 2016-11-05 4:07 PM, Al Kossow wrote:
On 11/5/16 11:24 AM, Jason T wrote:
I'm guessing
it's far more due to IBM having never released anything close to
technical documentation on the architecture
S/32 - 36 are fairly well documented.
It's just non-trivial to do the work
and would require someone to reverse-engineer with a machine next to them.
S34 would probably be easier though since it only has one processor and
didn't have quite as much LSI in it.
If you need some place to dump the resulting scans and disk images, I can
put them on bitsavers. I still have several boxes of S/36 documentation in
the backlog.
The architecture of both the S/34 and S/36 is very similar and both of
teem include two processors the CSP and MSP. The CSP handled most of
the I/O operations as well as getting the system off the ground while
the MSP processor executed the user programs. Even the S/32 is very
similar. The S/32 was a single user machine with up to 64K of memory, a
10MB disk and either a dot matrix or belt printer built in. The S/34
added more memory and multi user capability. S/36 again increased the
maximum memory, had faster processors, a much improved user interface on
the OS (SSP) and added one more instruction. The MSP memory in the S/34
and S/36 was divided into 64K segments and no program object could be
larger than 64K. The hardware itself is pretty unspectacular, the main
reason for the popularity of S/36 was the availability of software and
the ease of use of the system. They where commonly found in small
businesses that had no DP staff, at a lot of my S/36 customers, the
person looking after the S/36 was the controller. The user interface on
the AS/400 was largely based on the S/36 SSP.
Paul.