3 ms·

Fascinating... in the phrase "replaces the VAX chassis, CPU, memory, KWV11-C clock and mass storage", the clock being mentioned separately intrigued me, so i go

by rob74 5y ago

Fascinating... in the phrase "replaces the VAX chassis, CPU, memory, KWV11-C clock and mass storage", the clock being mentioned separately intrigued me, so i googled it. Turns out that only the clock was a whole board full of good old TI 74x TTL chips - and a "used but working" board goes for 345$ on eBay (https://www.ebay.de/itm/M4002-KWV11-C-MODULE-USED-AND-WORKING/161265624922 https://www.ebay.de/itm/M4002-KWV11-C-MODULE-USED-AND-WORKIN...)...

TheOtherHobbes 5y ago
Compared to x nm VLSI, TTL and ECL are ridiculously low density. And soooo sloooow. DEC were very pleased with themselves when they got to ~40VUPs in the later ECL models, but a full modern VLSI - not FPGA - implementation wouldn't break a sweat at 1000VUPs.
dfox 5y ago
What seems particularly interesting is that the board seems to really be just an RTC, yet does not have any obvious place for backup battery and has 10MHz oscillator on it.
cbm-vic-20 5y ago
The first-gen PDP-11's CPU was just a couple of boards full of good old TTL chips.
- noneeeed 5y ago
  I remember reading an old paper on some funky experimentat user-interface that used a pair of PDP-11s (possibly, might have been event older) essentially wired together at the busses, with extra instructions added with new logic in TTL silicon, I think it was for doing the maths for the vector graphics. It was amazing the amount of hardware hackery that was necessary to build these experimental systems.
  - Taniwha 5y ago
    Actually I think those were Vaxen https://gunkies.org/wiki/VAX-11/780#Dual-CPU_experiment https://gunkies.org/wiki/VAX-11/780#Dual-CPU_experiment
- GeorgeTirebiter 5y ago
  Yes, the pdp-11/20, released in 1969. Core memory only. In my opinion, it took the pdp-11/45 to firmly establish an impressive new line of machines, separate and more powerful than the pdp-8 line. But, in DEC's way of thinking, it's instructive to note that a pdp-11/40 was used as the console of the DECsystem-20. Separately, it's a shame we no longer have 36-bit machines; 36-bit ints would hold time_t just fine, and 72-bit doubles will work great for science. Oh well. What we're stuck with now bytes.
- deleted 5y ago
  [deleted]

by rob74 5y ago

TheOtherHobbes 5y ago

Compared to x nm VLSI, TTL and ECL are ridiculously low density. And soooo sloooow. DEC were very pleased with themselves when they got to ~40VUPs in the later ECL models, but a full modern VLSI - not FPGA - implementation wouldn't break a sweat at 1000VUPs.

dfox 5y ago

What seems particularly interesting is that the board seems to really be just an RTC, yet does not have any obvious place for backup battery and has 10MHz oscillator on it.

cbm-vic-20 5y ago

The first-gen PDP-11's CPU was just a couple of boards full of good old TTL chips.

noneeeed 5y ago
I remember reading an old paper on some funky experimentat user-interface that used a pair of PDP-11s (possibly, might have been event older) essentially wired together at the busses, with extra instructions added with new logic in TTL silicon, I think it was for doing the maths for the vector graphics. It was amazing the amount of hardware hackery that was necessary to build these experimental systems.
- Taniwha 5y ago
  Actually I think those were Vaxen https://gunkies.org/wiki/VAX-11/780#Dual-CPU_experiment https://gunkies.org/wiki/VAX-11/780#Dual-CPU_experiment
GeorgeTirebiter 5y ago
Yes, the pdp-11/20, released in 1969. Core memory only. In my opinion, it took the pdp-11/45 to firmly establish an impressive new line of machines, separate and more powerful than the pdp-8 line. But, in DEC's way of thinking, it's instructive to note that a pdp-11/40 was used as the console of the DECsystem-20. Separately, it's a shame we no longer have 36-bit machines; 36-bit ints would hold time_t just fine, and 72-bit doubles will work great for science. Oh well. What we're stuck with now bytes.
deleted 5y ago
[deleted]