Re: OT - Reminiscence



On Aug 9, 9:17 am, "Lloyd E. Sponenburgh" <lloy...@xxxxxxxxxxxxxx>
wrote:
Heh! I caught a glimmer of the "old days" of computing yesterday. I read a
brief reference to the Data General Nova mini-computer.

I got into computing just at the "knee" of the computer technology
explosion. When I started, we had some really "large" mini installations to
maintain in medical billing offices all over the southeast. Now, these
certainly weren't mainframe computers; no. Each computer system - sans
glass teletype terminals - fit in a single 54" x 19" RETMA rack. But wow,
what capacity they had!

---------------------------------------

The Nova-1200 mini ran at 1200 nanoseconds per Clear/Write, Read/Write, or
Read/Refresh memory cycle (thus its name). The largest instruction
(indirect memory reference) was two words (three memory cycles) long, so it
could run the average program at about 200,000 instructions per second.
That was faster than many mainframes! These babies really COOKED!

The 15-bit address space supported up to 16K, 16-bit words of magnetic core
memory (up to 8K on a single 15" square circuit board)-- HUGE! In a 54"
rack, you could just find room for four Xerox/Diablo model 33 disk drives
and power supplies. At only $5400 and 2.5MB each, that allowed you to have
up to TEN MEGABYTES of disk storage. If you had the room, the controller
could address up to 20MB! (but that would take two racks) There wasn't even
a doubt that nobody - but NObody - would ever fill up 20MB. Most large
radiology practices were able to store their entire patient billing database
in about 7.5Mb.

The Nova-1200 with its standard-height chassis would accomodate the cpu
board, the memory boards, the disk controller, and up to three (THREE!)
teletype interface boards! Up to THREE people could use the computer at
once!(well, they had to give up one terminal during printing... the printer
shared a serial interface). Each user ran in his/her own dedicated 4K-word
partition in memory, and the OS's interrupt, I/O, and disk driver routines
ran in the remaining 4K. Applications were swapped in and out from disk in
single-read chunks as large as 2K words per read. (16K was the largest read
the Diablo-33 controller would support).

The interfaces and Hazeltine 2000A terminals really screamed, too. They
could display stuff at up to 1200 baud. Actually, the terminals supported
up to 2400, but you had to insert cursor positioning and scrolling delays
for anything faster than 300 baud (yes, they even had a 110 baud setting).
It took some time to scroll a screenful of core memory one line up. (yeah...
the terminals actually had CORE! Two whole K bytes of core!) Green P-38
phosphor (high-persistance) to eliminate screen refresh flicker. So, green
characters on black. (cool! Color!) The terminals weighed about 80lb
each, with detachable keyboard --high-tech keyboards, too! None of these
clacky Microswitch keys; no. These had matrix-scanned capacitive key
sensing! Those 28-odd column/line mosfets had problems with static, though.

Our GE Terminet-300 printers handled straight throughput up to 300 baud,
with artificial delays after paper motion. There was none of this silly
"checking 'busy'" on the printer interface. You just slammed characters out
to the printer, and did a 400ms wait in software after each linefeed, or two
seconds for a form-feed -- simple. You could actually print an entire
medical bill in under a minute!

The entire system weighed less than 1100lb, and it required LESS than 36,000
BTU of cooling. What efficiency!

And the real stinger? It cost less than $80,000.00. Nearly any
medium-sized business could afford one!

-----------------------------------------------------------

Slew forward twenty-nine years. The whole system, including 1Gb of memory,
will fit on a 4"x6" board. It runs at 3.7GHz. You can carry a terrabyte of
disk in your shirt pocket. Your printer fits in the space of a paperback
novel and prints ten color pages per minute. The thing communicates via
ethernet at 100Mb/s. All-up, it weighs five pounds, and displays its work
in high-rez, flat-screen color.

You can power the whole thing off a 12-ounce battery. It costs $1000.00,
all-up.

I'm glad I got in (and out) when I did. The wonders I've seen...

LLoyd

LLoyd,
I do indeed remember the NOVA 1200 mini-computer!
Such fun I had in college flipping the switches on the
front panel to set the address and data in order to program
it. :-)
Thanks for bringing back a flood of memories!
Tom the Canuck

.



Relevant Pages

  • OT - Reminiscence
    ... Each computer system - sans glass teletype terminals - fit in a single 54" x 19" RETMA rack. ... The largest instruction (indirect memory reference) was two words long, so it could run the average program at about 200,000 instructions per second. ... At only $5400 and 2.5MB each, that allowed you to have up to TEN MEGABYTES of disk storage. ... Actually, the terminals supported up to 2400, but you had to insert cursor positioning and scrolling delays for anything faster than 300 baud. ...
    (rec.pyrotechnics)
  • Re: OT - Reminiscence
    ... Read/Refresh memory cycle. ... up to TEN MEGABYTES of disk storage. ... The interfaces and Hazeltine 2000A terminals really screamed, ... for anything faster than 300 baud. ...
    (rec.pyrotechnics)
  • Re: OT - Reminiscence
    ... Read/Refresh memory cycle. ... to have up to TEN MEGABYTES of disk storage. ... printer shared a serial interface). ... The interfaces and Hazeltine 2000A terminals really screamed, ...
    (rec.pyrotechnics)
  • Re: OT - Reminiscence
    ... Read/Refresh memory cycle. ... to have up to TEN MEGABYTES of disk storage. ... printer shared a serial interface). ... The interfaces and Hazeltine 2000A terminals really screamed, ...
    (rec.pyrotechnics)
  • Proposed Assembler Commands
    ... ACM Automatically Clear Memory ... BKCRDR Backspace Card Reader ... BKSPD Backspace Disk ... EIAO Execute In Any Order ...
    (sci.electronics.design)