6 ms·

The best I could find was a Dhrystone Benchmark of about 800MIPS for the PDP11/70. The Raspberry PI3 is rated 2,411MIPS. This emulator must be much faster tha

The best I could find was a Dhrystone Benchmark of about 800MIPS for the PDP11/70. The Raspberry PI3 is rated 2,411MIPS. This emulator must be much faster than the original PDP11 even with the emulation software.

zh3 4y ago
800MIPS? Not off an 11/70, for sure - much, much slower than that. 11/23's were as fast (or faster, depending on options and application) and they were maybe a single MIP or so (still got a couple of PDP11's kicking about, every so often I fire them up just to check my hearing).
- bdavis__ 4y ago
  From memory. (The original) VAX 11/780 was a 1 MIPS machine. 32 Bit. pdp 11 was a slower machine. plus it was 16 bit. slow clock, a relatively cheap o'scope could be used to snoop the buses.
  - zh3 4y ago
    Indeed, back in the day we bolted QBus backplanes to the side of DIN41612 backplanes and wire-wrapped across to a bunch of boards each with 100+ TTL chips on them (the 5V PSUs were something like 120A). The bus clocked at around a MHz, hence loosely the instruction rate (and back then, the addressed memory or peripheral needed to ack the bus cycle or there'd be a bus fault).
  - timonoko 4y ago
    50 cent ESP-8266 would make excellent PDP-11. Except much too much memory. And 20 times too fast.
    - dekhn 4y ago
      https://www.espressif.com/en/news/news/ESP32-Powered_PDP-11 https://www.espressif.com/en/news/news/ESP32-Powered_PDP-11
  - williamDafoe 4y ago
    The original PDP-11/70 was 0.7 vax mips. So it was 70% as fast as a Vax 11/780. I believe (from memory) the Vax 11/780 could do ~1757 dhrystone 2.1 mips so a PDP-11/70 would be about 1230 dhrystone mips. https://wiki.cdot.senecacollege.ca/wiki/Dhrystone_howto https://wiki.cdot.senecacollege.ca/wiki/Dhrystone_howto
- j_not_j 4y ago
  ..."just to check my hearing" I got a good laugh out of that....
  - watsocd 4y ago
    Yes. Looks like I slipped a few decimal points.

zh3 4y ago

800MIPS? Not off an 11/70, for sure - much, much slower than that. 11/23's were as fast (or faster, depending on options and application) and they were maybe a single MIP or so (still got a couple of PDP11's kicking about, every so often I fire them up just to check my hearing).

bdavis__ 4y ago
From memory. (The original) VAX 11/780 was a 1 MIPS machine. 32 Bit. pdp 11 was a slower machine. plus it was 16 bit. slow clock, a relatively cheap o'scope could be used to snoop the buses.
- zh3 4y ago
  Indeed, back in the day we bolted QBus backplanes to the side of DIN41612 backplanes and wire-wrapped across to a bunch of boards each with 100+ TTL chips on them (the 5V PSUs were something like 120A). The bus clocked at around a MHz, hence loosely the instruction rate (and back then, the addressed memory or peripheral needed to ack the bus cycle or there'd be a bus fault).
- timonoko 4y ago
  50 cent ESP-8266 would make excellent PDP-11. Except much too much memory. And 20 times too fast.
  - dekhn 4y ago
    https://www.espressif.com/en/news/news/ESP32-Powered_PDP-11 https://www.espressif.com/en/news/news/ESP32-Powered_PDP-11
- williamDafoe 4y ago
  The original PDP-11/70 was 0.7 vax mips. So it was 70% as fast as a Vax 11/780. I believe (from memory) the Vax 11/780 could do ~1757 dhrystone 2.1 mips so a PDP-11/70 would be about 1230 dhrystone mips. https://wiki.cdot.senecacollege.ca/wiki/Dhrystone_howto https://wiki.cdot.senecacollege.ca/wiki/Dhrystone_howto
j_not_j 4y ago
..."just to check my hearing" I got a good laugh out of that....
- watsocd 4y ago
  Yes. Looks like I slipped a few decimal points.