KFKI TPA-1148



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:

• 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.
• Processor:

2-3 new instructions, supervisor CPU mode added, separate user-system I/D spaces
• 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.
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 PDP-11/34's frontpanel. The TPA-1148 was successful: more than 200 were sold (from which 80 were TPA1140 upgrades).
Varga Ákos Endre

Back to the TPA pages
About the author