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Digital Memory's Evolution

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Stargzer
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Re: Magnetic Card Memory and Memory Emulating a Disk Emulating Memory
Stargzer   10/22/2013 4:21:43 PM
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Ron and David:

Upon reflection I'm sure it was NCR because it was at a bank.  They still used the NCR forms for planning and documentation by systems analysts and programmers.  A quick look at Wikipedia found an article on the NCR CRAM - Card Random Access Memory:  http://en.wikipedia.org/wiki/NCR_CRAM.  The article documents the mis-drops that the older programmers told me about.  There's a link at the end of the article to a PDF of the NCR Product Brochure, so you can see how large a monster this was.  You can also see the notches on the cards and the shape of the rods, leading to the binary selection of a card.

I'm sure many of the BUNCH (Burroughs, UNIVAC, NCR (National Cash Register), CDC (Control Data Corp), and Honeywell) had similar products.  The BUNCH suceeded IBM and the Seven Dwarves (NCR, Burroughs, Control Data Corporation, General Electric, Honeywell, RCA and UNIVAC; SDS (Scientific Data Systems) was also active at that time).

JGrubbs
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Barrier Grid CRT Memory
JGrubbs   10/22/2013 10:41:30 AM
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In 1959-1960 the company that I worked for had a contract to manufacture the Arithmetic Unit of a vacuum tube based computer that was being built at the University of Oklahoma. It was a copy of a computer being built at Rice University. The memory used Barrier Grid CRT storage tubes. The computer had a capacity of 32768 words of 56 bit length.

 "A Brief History of the Rice Computer 1959-1971" is very interesting read about the hardware and architecture of the computer.

http://www.cs.rice.edu/History/R1/

 

JanineLove
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Re: More Memory= More Code
JanineLove   10/22/2013 8:37:26 AM
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You've got that right @betajet. And it applies to documents too. For example, there seems to major penalties for formatting codes (or Apple to Microsoft, I'm not sure which). I tried to save a .pages file as a .doc file and it increased in size by 20X. Bloat, bloat, bloat.

DU00000001
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MBytes vs. kBytes (!)
DU00000001   10/22/2013 8:24:37 AM
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I was slightly irritated by the 18.4(32) MBytes of RAM (core memory).

Doing some research I found the following:

Min.:    4,096 Words (=18,432 Bytes) of core memory
Max.: 32,768 Words (...)

About the tape capacity:
IBM documents give up to 900,000 Words (=4,050,000 Bytes) per tape @
33.5 Words/in (150,75 Bytes/in).

Thus the tape has to be roundabout 2240 ft long.
(When being up and running) It could be read within 10 min. - resulting in a tape speed of incredible 74.6 in/s.

David Ashton
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Re: Magnetic Card Memory and Memory Emulating a Disk Emulating Memory
David Ashton   10/21/2013 7:21:36 PM
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@Ron Neale - re Mag Stripe Ledger Cards - they did.  My dad used to work for Burroughs (in sales, unfortunately, not in tech) but I remember those cards.  I think the machines that used them were the L4000 series but it's a long time back, I was just a kid and I'm probably wrong.

Ron Neale
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Re: Magnetic Card Memory and Memory Emulating a Disk Emulating Memory
Ron Neale   10/21/2013 6:41:17 PM
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Stargazer:-I think The Burroghs Corporation had a ledger card that had a magnetic strip along one side. Burroughs also invented virtual memory that I think used a drum, but it was not until another company promoted it that it really took off. I think the other company was IBM.

Stargzer
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Magnetic Card Memory and Memory Emulating a Disk Emulating Memory
Stargzer   10/21/2013 3:33:01 PM
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No one seems to have mentioned magnetic card memory.  It was popular on early HP programmable desktop calculators (circa 1969-1973 - I still have two kinds somewhere ...).  I encountered a reference to another kind in my first job, at a bank.  Their pre-IBM 370 series computer (I think it was an NCR) had a mass-storage device that used magnetic strips with a series of binary-coided notches in the top of each card.  They were suspended on rods and the rods were rotated so the correct card fell down into the reader (usually!).  A programmer told me they often had mis-drops or jammed cards.  Cheaper than a drum, I guess.

Back about 1972 or 1973, the newsletter of the Boston College data center was called "Hard Core."  When they replaced their IBM 360 Model 40 with an IBM 370/145, there was a several-issue discussion on whether they needed to change the name of the newsletter since there was no longer any such thing as hard core.  I never found out if they changed or not.

IBM once had a head-per-track hard drive that was used to emulate memory when semiconductor memory was too expensive and conventional hard drives were too slow for paging.  Later, as the cost of semiconductor memory fell, a memory manufacturer made a plug-and-play replacement for the head-per-track disk using solid-state memory.  Memory emulating a disk that emulated memory! 

Stargzer
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Re: Cold to the Core
Stargzer   10/21/2013 3:10:08 PM
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Ron Neale:  One day the local corner shop ventured to equire why I regularly purchased cigarette papers and never any tobacco-perhaps suspicious that I was obtaining my "smoking material" what ever that was from other sources.

Two rolling papers memories: 

Back about 1970, a store in Worcester, MA was selling tobacco and pre-rolled papers and a machine to inser tobacco and a filter.  There was much concern when they noticed that all of the college students seemed to be buying the papers and the rolling machine and not the tobacco or filters.

Fast forward about 25 or so years and my daughter was learning to play the flute.  The guy who re-padded her flute said she should carring a package of cigarette papers to put under the pads on the valves to absorb the moisture from playing.  How would one explain that these days?  Or buy the papers?  They used to be in all the stores that had a tobacco section.  And no, I would not loan her the insert from my Cheech & Chong "Big Bambu" album.

 

Etmax
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Re: Cold to the Core Ah delay lines
Etmax   10/18/2013 3:27:45 AM
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@ Ron "Memories that Forgot" not unlike DRAM :-)

betajet
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Re: Where's the paper tape?
betajet   10/17/2013 3:08:40 PM
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8080 has a very simple, pretty regular machine language so hand-translating between ASM and octal bytes isn't hard.  I had a Heathkit H-8, which included a marvelous single-page 8080 instruction table arranged in octal order.  After a while, you can do most of the translations from memory.  The PDP-8 and PDP-11 are even easier because of better regularity.  In constrast, ARM instruction bits are all over the place in the later versions.  Hand-assembling ARM would easily beat out your brother in the crazy department.

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