IBM 2321 Data Cell
The IBM 2321 Data Cell is a discontinued
System/360. It was announced with System/360 in April, 1964. It holds up to 400 megabytes of data, with an access time of 95 milliseconds to 600 milliseconds, depending on the addressed strip position and data arrangement in each data cell.[1]
The 2321 was withdrawn from marketing in January, 1975.
Characteristics
The 2321 houses up to ten removable and interchangeable data cells, each containing 40 megabytes. Each data cell contains 200 strips of
In comparison to the contemporary
IBM 2311 Disk Device
, the IBM 2321 Data Cell Device holds 55 times more data, while being only seven times slower (85ms and 600ms access times respectively). One fully loaded IBM 2841 Control Unit connected with eight IBM 2321 Data Cell Devices has the capacity of 441 IBM 2311 Disk Devices, which would need to be connected to 56 IBM 2841 Control Units, which would require seven data channels.
The Data Cell makes use of three concurrently operating separate seeking systems: a servo-hydraulic one to rotate the bins to select the proper subcell, and two
psi and despite a lot of folklore
about oil leaks, they were very rare. The oil sump holds 5 US gallons (19 L).
Although its storage medium is tape, the 2321 is classified as a
direct access storage devices, i.e., a disk drive, with a 6-byte seek address of the form ØBBSCH (hexadecimal) where the first byte is zero and the remaining bytes address the Bin (i.e., cell and sub-cell), Strip, Cylinder and Head.[3][4]
Trivia
The 2321 was whimsically known as the "noodle picker" since the removable magnetic strips were flexible and resembled lasagna noodles.[5]
See also
References
- ^ IBM Archives - 2321 data cell drive
- ^ IBM Corporation (1964). IBM System/360 System Summary (PDF). p. 25. Retrieved Apr 14, 2019.
- ^ a b IBM System Reference Library, IBM System/360 Component Descriptions, Form A26-5988 (PDF).
- ^ Generically, at the OS level, IBM defined the six bytes as BBCCHH, for Bin, Bin, Cylinder, Cylinder, Head and Head respectively.
- ^ The 2321 Data Cell & Joe Rufin
External links
- The IBM 2321 Data Cell Drive at Columbia University
- Shugart, Alan; Tong, Yang-hu (1966), "IBM 2321 data cell drive", Proceedings of the April 26–28, 1966, Spring Joint Computer Conference, New York City, New York: Association for Computing Machinery (ACM): 335–345
- The IBM 2321 Data Cell Drive for portions of IBM manual.
- Close up photo of Data Cell drive
- IBM System/360 Component Descriptions - IBM 2841 and Associated DASD pages 65 to 72 describe the IBM 2321