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NCR Card Random Access Memory (CRAM)

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Cercavo informazioni sul SO IMOS V, quando sono incappato in questo
sistema di storage, un accrocchio a base di card magnetiche
selezionabili che venivano fatte cadere su un cilindro rotante, sul
quale aderivano pneumaticamente, per essere lette e scritte; poi
venivano fatte tornare al loro posto.
La selezione avveniva mediante dei fori attraverso i quali passavano
delle bacchette sagomate le quali, ruotando, liberavano la card
specificata dal relativo numero (in codice binario). :)

https://en.wikipedia.org/wiki/NCR_CRAM

cito la parte divertente:

«Cards were dropped by changing the card rods to a binary configuration
and release the two outside "release" rods. Air was blown over the top
of the cards to keep them separated, and to increase the dropping speed.
Once on the rotating "drum" a series of positive and negative air
pressure chambers pulled the card across a magnetic read-write head.
After one or more passes over the head, where data is written to or read
from the card, a release gate allow the card to be "thrown" along a
raceway over the card deck, and onto a "loader" mechanism. The loader
used a group of electro-magnetic solenoids to slam the card back onto
the control rods. The unit was a monster with two large electric motors
that drove four large vacuum/blowers. It was possible to have up to five
cards in motion at any point in time; one dropping, one on the drum, two
in the return transport, and one being loaded back onto the deck.

If the card didn't succeed in dropping there was a "magic wand" similar
to a pencil available to solve the problem.

One feature of this device was the potential for a "double drop", where
two cards would drop at once, due to a break in a notch on one card, or,
more commonly, a card being held by one rod being dislodged by the
adjacent card dropping, usually cards 000 (the deck directory card) and
001 which resulted in the necessity of recreating the directory. This
would result in a high pitched noise with which operators were very
familiar and could hear even outside the computer room, and damage to
the cards. These were called "screamers", while the opposite problem,
cards that wouldn't drop, were called "hangers".

Another interesting feature was that, should an operator accidentally
drop all the cards from a cartridge, they could be replaced without
worrying about order. The order of the cards was not important because
of the notch encoding system.»

In fondo alla pagina c'è un link alla brochure, che contiene foto e
illustrazioni, tra cui uno schema del funzionamento.

Altrove leggo che l'acronimo veniva letto come "Chaos Reaches All-time
Magnitude", per la sua affidabilità. ^_^;;;
Però riconoscono che era un vero sistema di memoria ad accesso casuale e
che funzionava bene, a patto di controllarlo a vista. :)

CYA

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NCR Card Random Access Memory (CRAM) "zfkirone@gmail.com" <zfkirone@gmail.com> - 2020-05-18 04:44 +0200
  Re: NCR Card Random Access Memory (CRAM) "zfkirone@gmail.com" <zfkirone@gmail.com> - 2020-05-18 04:47 +0200
    Re: NCR Card Random Access Memory (CRAM) "Dino.Baldi" <dino.baldi@gmail.com> - 2020-05-18 06:15 -0700
  Re: NCR Card Random Access Memory (CRAM) G. <gerry77@no.spam.mail.com> - 2020-05-20 20:04 +0200
    Re: NCR Card Random Access Memory (CRAM) "zfkirone@gmail.com" <zfkirone@gmail.com> - 2020-05-24 09:30 +0200
      Re: NCR Card Random Access Memory (CRAM) G. <gerry77@no.spam.mail.com> - 2020-05-24 21:03 +0200
        Re: NCR Card Random Access Memory (CRAM) "zfkirone@gmail.com" <zfkirone@gmail.com> - 2020-05-25 18:37 +0200
          Re: NCR Card Random Access Memory (CRAM) G. <gerry77@no.spam.mail.com> - 2020-05-26 15:21 +0200
          Re: NCR Card Random Access Memory (CRAM) Giuseppe³ <miaooaimATtiscaliDOTit@xxx.xxx> - 2020-05-26 19:30 +0200
            Re: NCR Card Random Access Memory (CRAM) "zfkirone@gmail.com" <zfkirone@gmail.com> - 2020-05-26 19:56 +0200
              Re: NCR Card Random Access Memory (CRAM) Giuseppe³ <miaooaimATtiscaliDOTit@xxx.xxx> - 2020-05-26 20:47 +0200
              Re: NCR Card Random Access Memory (CRAM) Giuseppe³ <miaooaimATtiscaliDOTit@xxx.xxx> - 2020-05-26 20:53 +0200
                Re: NCR Card Random Access Memory (CRAM) "zfkirone@gmail.com" <zfkirone@gmail.com> - 2020-05-26 21:46 +0200
                Re: NCR Card Random Access Memory (CRAM) Giuseppe³ <miaooaimATtiscaliDOTit@xxx.xxx> - 2020-05-26 22:43 +0200
              Re: NCR Card Random Access Memory (CRAM) G. <gerry77@no.spam.mail.com> - 2020-05-27 11:26 +0200
                Re: NCR Card Random Access Memory (CRAM) "zfkirone@gmail.com" <zfkirone@gmail.com> - 2020-05-27 13:44 +0200
                Re: NCR Card Random Access Memory (CRAM) G. <gerry77@no.spam.mail.com> - 2020-05-27 18:52 +0200
                Re: NCR Card Random Access Memory (CRAM) scap61 <scap6161@yahoo.it> - 2020-05-28 00:17 -0700

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