Got a question....PDP? VAX?

From: Allison J Parent <allisonp_at_world.std.com>
Date: Fri Mar 12 23:25:12 1999

<I've been growing up in the age of "IBM era" of computers. The only non-IB
<(compatible) computers that I've worked on was an apple //c and a TRS-80

It has it's upsides.

<What I'm wondering, is what exactly is a PDP, or a VAX, or an Altair, or an
<of the other things that come up frequently on the list. Also - how is on
<of the computers (such as the Altair) operated, with all the switches and
<indicators? Is there a keyboard or a monitor with it?

Jason,

Here is a brief snapshot of some of those mentioned.

Altair <~1975-->1979>:
A very raw machine with a toggle switch and led front pannel. Its based on
the 8080 cpu. Unlike PCs there was no rom, no bios (it was being invented
around the same time). Boards used a BUS called S100 for the 100 pin
connector and a typical board would be a serial port, 8k ram, or maybe a
16line by 64 character video card. No monitor and keyboard like PCs, if
you had the bucks a TTY of the mechanical kind (ASR33) and it also allowed
paper tape.

PDP-8 <~1965--> 1991>:
PDP8 was a 12bit archetecture and in the real early days was like the altair
with lights, switches and core memory that didn't forget with the power off.
By the late 80s the PDP-8 was commonly know as DECMATEII and III and used a
CMOS version of the PDP-8 CPU. One of the longest running of the old iron.
OSes were created on this machine and would live on others. Best known are
RTS-8, OS/8, EDUSYSTEM, MUMPS, COS. used a lot for science(labs),
data aquisition and control systems.

PDP-11 <~1970--> CURRENT>
A 16 bit CPU useing complex instruction types and is the longest running
line of the oldies. It started as all TTL small scale integration and the
last 15 years of them are chips (J11 is the longest running of the chips).
Considered one of the most potent of the 16bit cpus with many rivals.
Boxes ranged from the tiny to real monsters. peak perfomance was about
1-2MIPS. Still considered by many to be a great programmers machine.
It ran RT-11, DOS, MUMPS, RSTS, RSX, UNIX and many more OSs. Many of the
single board versions (over 50,000 at Bridgeport Machine tools alone) were
built into NC tools.

VAX <~1978--current>:
DEC forsaw that 16bits was not enough for high performance computing and
created the 32bit VAX-11/780. the VAX-11 was droped for vax but it's part
of its roots. It's a very CISC machine, 32bits and is know for 24x365
kinds of operations, they were workhorses and carried the superminicomputer
banner for many years. Later versions were of the smaller form with the
MicroVAX being the first chip level implmentation. They set a standard for
perfomance that is unique (VUP). the common OS is VMS, ULTRIX (DEC
BSDversion of unix). VAX was not a front pannel machine and many of the
larger ones had a PDP-11 (in the form of an 11/03 or Pro350/380) as the
"front end". Their sizes ran from room fillers to the small VS2000 or
later 3100 workstation pizza boxes. systems like the nearly 10year old
VS3100 are still considered good mailservers and small web servers and do
not crash when loaded to the max+1.

Hope that helps.

Allison
Received on Fri Mar 12 1999 - 23:25:12 GMT