5 Mar
2002
5 Mar
'02
2:01 a.m.
Brian Chase wrote:
Also, to keep things on topic, does BART still use any
PDP-8 systems?
I read someplace, probably a few years ago now, that they used PDP-8s
for their control systems.
BART never used PDP-8's as part of the _train_ control system. That
task was originally delegated to a set of Westinghouse machines, with
separate control processors for the maintenance yard. That proved to be
unworkable almost immediately, which resulted in a new architecture
from the LBL RTSG that stuck trackside block-control
processors into the
system and then restricted headways such that only one train
could
occupy a block at a time. This had a _major_ impact on system capacity,
since BART was designed to be "semi-blockless", in the sense that
multiple trains were supposed to be able to occupy each block since the
system was going to have absolute knowledge of where each train was at
any given moment.
Logica was contracted sometime in the late 80's to create a new
centralized control system which was rumored to be based on DG MV series
machines. I have no idea where that effort ever went (other than
grossly overbudget).
Oh, and the PDP-8's? They were rumored to have run the annuciator
system and, in some cases, station environmental controls.
--
Chris Kennedy
chris(a)mainecoon.com
http://www.mainecoon.com
PGP fingerprint: 4E99 10B6 7253 B048 6685 6CBC 55E1 20A3 108D AB97