Got a question....PDP? VAX? - test-drb@ccmp.vtda.org

12 Mar 1999

Larry:

Given your start in computing in the mid-fifties, you must now be
in your mid-sixties.  I was one who started in the early 70's (as
early as my 12-th year) and am now 41.   The machine was
an IBM 370/155 with 1MB of main memory, and the language was
APL (APL*PLUS from Scientific Time Sharing).

Well, it is true that the machines of the 50's were the so called
Unit Record devices and the low quality mainframes of the day,
like the 7090, the 1620 (if I get the numbering correct) and the
1401 (all of IBM fame).  I had the privilege of working with such
Unit Record devices, and even to have programmed a few of the
old style plug boards.

I am greatful that those days are over!

William R. Buckley

-----Original Message-----
From: Lawrence Walker &lt;lwalker(a)mail.interlog.com&gt;
To: Discussion re-collecting of classic computers
&lt;classiccmp(a)u.washington.edu&gt;
Date: Friday, March 12, 1999 10:28 PM
Subject: Re: Got a question....PDP? VAX?

On 12 Mar 99 at 17:53, Mike Ford wrote:

...
  >Hi!
 >
 >I've been growing up in the age of "IBM era" of computers.  The only
non-IBM
...
  >(compatible) computers that I've worked on was
an apple //c and a TRS-80
 >model III that nearly caught my basement on fire.  I'm 16 years old, so I
 >haven't had any experience with any pre 1980's stuff (other than the
//c).
...
  >
 >What I'm wondering, is what exactly is a PDP, or a VAX, or an Altair, or
any
...
  >of the other things that come up frequently on the
list.  Also - how is one
...
  of the
computers (such as the Altair) operated, with all the switches and
indicators?  Is there a keyboard or a monitor with it? 
 Wow, do you want the one or two paragraph history of computing as we know it?
...

 Maybe Moore's law explains it best, every couple of years computers get
 twice as fast, for half the money and size. Now Start with a typical
 present day Pentibum II 400 Mhz 128 MB ram 10 GB hard drive that sells for
 $2000 and go back in time 20 years (about 10 of Moore's cycles). Computers
 were 1000 times slower, bigger, and more expensive. That was a different
 world, and you had to treat such valuable resources differently. People,
 and really only a small favored few, had to share the computers, and time
 24 hours a day was highly prized.

 Around 1970 a computer about as powerfull as a present day $100 calculator
 cost about $10 million and required a large secure and temperature
 controlled room. That was the mainstream of mainframe computers. The
 computer was the size of a kids play house, and all around it in the large
 room were "peripherals" designed to keep the main cpu busy working all the
 time.

 Away from the main IBM oriented data processing shops, dozens of smaller
 companies fought for the minicomputer market. Smaller, and less powerfull
 in absolute terms, these units were targeted at the scientific and
 industrial users who needed the computational or control that only
 computers allowed. Minicomputers weren't that different from mainframes,
 just scaled down in some senses, and optimized in others.

 Digital Equipment Corporation, DEC was one of these minicomputer companies,
...
  and its PDP line was hugely popular in many areas.
Industry, banking,
 telephone, and most important universities. The DEC PDP series became the
 platform that many computer scientists experiemented on, and many students
 still didn't get to use. As Moores law improved the lot, the VAX line came
 out, and people logged on with gusto forever after.

 Oh, those switches and lights are mostly because the hardware and software
 used to screw up fairly often, and by looking at the lights, and flipping
 switches  the operation of the computer could be single stepped (one
 instruction per button push) and errors identified so they could be
 corrected.
 Wow, great thread. Thanks Jason.

I tend to think of the evolution of computers in physical relation to
myself.

In an incarnation in the mid-fifties, I worked for a large government
department as a "junior IBM operator" I worked sorting IBM cards,
reproducing
cards that were "bent, mutillated, and spindalled", and wired peg-boards to
interpret the data contained on those cards, which were "punched" by a
room-full of typist "punch-card operators". Even tho this was a large gov.
apparatus, the machines could only be "leased" not bought from IBM and
even some programs were rented. In a temperature-controlled room
filled with machines spinning large metal tape-reels were the "high priests"
of this genre. I never entered that room. It had windows where you could see
the esoteric operatives at work.
In the 70's I worked for a large railway keeping track of boxcars entering
and
leaving the Yard. I would write up a report each day and submit it to the
computer room. Again, a temperature and environment controlled room, but
the "priests" were fellow workers who, tho aloof, I could talk to. And I
could
even enter the "temple"
Fast forward to the early eighties in a tech school.
Each student had a terminal ID to access the main computers but they were
at another location which I never saw. The school could even have been
renting
service space from another provider. But in the course I actually used a
real
computer more or less, an ET3400, to explore the godlike ways. We also had
a trainer in which you could enter and step thru each program using switches
with LED indicators. In a tech-course a few years later I was introduced to
floppydisks using an Osbourne. We smoked and drank cokes using them.
To me the great flowering of the 8-bits was the demystifying of computer
arts. Unfortunately, I feel OS2, Win9x, and NT are removing us from
that control ,as against the "high Priests" of VAX. It's amusing to
remember that my professors looked blank when I asked them about Unix
in 83 after reading about it in "Electronics" magazine. I explained it as
simply a method of disk storage organisation and access.
Altho the computer world has changed mightily I think the "deification"
remains with the minis and mainframes and Unix is it's theology. I
appreciate Linux precisely because it has an empowering feel to it.
That is the glory of the personal computer.
I have a PDP-8 maintenance manual and an IBM VS360/370 programmers
manual and at some point I will study them. But neither can give me the joy
of
an old "populist" 8-bit programming manual, with a code-bloatless program to
automate your toaster on a 64k ram machine. That was elegance.
Flame away.

ciao larry
lwalker(a)interlog.com