CRAM, or Card Random Access Memory, model 353-1, was a data storage device invented by NCR, which first appeared on their model NCR-315 mainframe computer in 1962. A data storage device is a device for recording (storing information (data NCR Corporation ( is a technology company specializing in products for the retail and financial sectors The NCR 315 Data Processing System, released in January 1962 by NCR, was a second generation Computer. Mainframes (often colloquially referred to as Big Iron) are Computers used mainly by large organizations for critical applications typically bulk data
A CRAM cartridge contained 256 3x14" cards with a PET film magnetic recording surface. Biaxially-oriented Polyethylene terephthalate (boPET Polyester film is used for its high Tensile strength, Chemical and dimensional Stability Each Deck of cards could contain up to 5. 5 MB of alphanumeric characters. The cards were ingeniously suspended from eight d-section rods, which were selectively rotated to release a specific card, each card having a unique pattern of notches at one end. The selected card was dropped and wrapped around a rotating drum to be read or written. Each cartridge could store 5. 5MB. Later versions of the CRAM; 353-2 and 353-3 used Decks of 512 card, thus doubling the storage capacity of each unit. The CRAM was also available on NCR's third generation NCR Century 100 as the NCR/653-100. NCRs first all integrated circuit computer The 615-100 Series integrated a complete data processing system had 16KB or 32KB of short rod memory 80-column card reader or paper tape reader Each card contains seven tracks containing 1550 slabs each of them. Normally the track was initialized with a four slab header containing the cartridge number (2), the card number and the track number.
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 load 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 "interesting" 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. This would result in a high pitched noise with which operators were very familiar and would hear even outside the computer room.
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.
CRAM was very successful in the 1960s, offering a fast and secure storage alternative to magnetic tape, but was superseded by the development of superior disk drive technology. Magnetic tape is a medium for Magnetic recording generally consisting of a thin magnetizable coating on a long and narrow strip of Plastic. Disk storage is a general category of a Computer storage mechanisms in which data is recorded on planar round and rotating surfaces ( disks, discs, or
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