1982. The TPA-1148 was an upgrade to the TPA-1140,
with the goal to make it compatible with the PDP-11/70,
the strongest PDP-11 around. And they succeded: although the CPU itselt
was slower than the original, the operating systems (mostly RSX-11M, RT11
and UNIX) recognised the TPA as a PDP-11/70!
The new features:
The picture on the top shows a TPA1140 system upgraded to 1148, you can
see the new (white) frontpanel, which bears a little resemblance with the
frontpanel. The TPA-1148 was successful: more than 200 were sold (from
which 80 were TPA1140 upgrades).
22-bit memory management:
Enabled the memory expansion to 2Mword (4MB), thus decreased the usage
of checkpoint (swap), but made the CPU a little slower.
2-3 new instructions, supervisor CPU mode added, separate user-system
Microprocessor console subsystem:
The 1148 had a Zilog Z80-based console system instead of the classic
"lights&switches" frontpanel. This inteligent device had automatic
terminal baud detection, enabled the "exam/deposit"-type debugging and
was able to run a few diagnostics and bootstraps from EPROM.
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