Re: {SPAM?} Re: [SLUG] The Storm

From: Chuck Hast (wchast@gmail.com)
Date: Mon Aug 16 2004 - 21:59:45 EDT


On Mon, 16 Aug 2004 08:07:23 -0400, Donald E Haselwood
<dhaselwood@verizon.net> wrote:
> By the way does anyone recall why a 1 & 0 is called a bit and there are 8 bits
> >to a bite?
>
> For awhile in the IBM world a byte was 6 bits. The "new" teletypes (really
> fast (110 baud), and really cheap--like $1K).
These were Modle 33's (the cheap ones) and model 35's (the expensive ones)
The 33's had a type cylinder and the 35's had a type pallet.Both came
in RO (Receive Only), KSR (Keyboard Send Receive), and ASR (Automatic Send
Receive)
The RO was only a printer, the KSR was keyboard and printer and the ASR was
Keyboard/perforator, printer, TD or transmitter distributor AKA tape reader.

The 33 was a "adjust by bending" machine you would ajust the blooming things by
bending bits and pieces into position. The 35 which was decended from
the venerable
Model 28 was a true adjustable wonder. Both these machines were
current loop either
20 or 60 ma loop, at about 150vdc. Believe me if you got across that
current loop it
would light your bulb more so if it was being keyed, that squaire wave
was always
good for a nice wakeup.. A full blown model 35 ASR could have more
than 3500 moving
parts. There were low voltage cards that were introduced later to
keep the current
loop out of the minicomputers, I worked for DEC and remember well
these machines.

I remember one TD which we called the "monkey" it would read the tape
like a regular
tape reader, but the head was mounted on a system of levers that would
allow it to
"climb" out on the tape as it came out of the perforator, and it would
read the tape up
to the punch face on the perf.

I remember the day I first saw the 1200 cps reperf, sounded like the
machine from
hell and it could go through tape at a ungodly rate. I am trying to
remembe what we
called the things.

After the 35 came the model 43 which like the 35 had a type pallet but
it had upper and
LOWER case, something that they previous machines did not have!!

All of this brings back my fond memories of the 28's and 35's, I used
to have a collection
of them back in Costa Rica. They were wonderful mechanical wonders in
their day, indeed
today they are still wonderful mechanical wonders.

> They had 8 bits with the new
> fangled ASCII code, whereas IBM's code...damn I forgot the name...but it
EBCD, seems like it was pronounced ebsidick, seems like it stood for Extended
Binary Coded Decimal.

> was it would sort the same as the Hollerith card codes, whereas ASCII's
> sort order was different. That was the era when Digital Equipment (DEC)
> was the upstart, and IBM was what today is the Microsoft of the computer
> market.
>

Yep, PDP-8's 9's, 10,s and the last one I saw before leaving DEC was the
PDP-11.

Ohh yea, and I remember well CORE MEMORY, you could load it up and
shut the machine down pull the core memory out and stick it in another
machine start it up and off it would go!!

DEC even had some people that would set back in a very quiet room and
replace cores on bad boards. A core was about the size of a period on a
small print page. It had 3 wires that went through it, Read, Write and Write
inhibit. There were 8+1 cores/bite if I recall. And those boxes would run
multiple processes and handle multiple TTY's

Also remember setting in front of the machine and keying in the bootloader, some
people knew it by memory, I never was that good.

We would key in enough to pull a paper tape and finish the load, and you were
up and running. Ahh those were the days, core and oil (for the TTY)....

-- 
Chuck Hast 
To paraphrase my flight instructor;
"the only dumb question is the one you DID NOT ask resulting in my going
out and having to identify your bits and pieces in the midst of torn
and twisted metal."
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