EP0090137A2
Expired / Lapsed
EP
⏱️ 0.0 years remaining
Access control system for digital data storage device
Assignee: International Business Machines Corp
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Filing: 1983-01-26
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Granted: —
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Expires: 2003-01-26
Abstract
Abstract A system for ensuring writing synchronism of a character string into non-contiguous blocks of buffer storage by updating the contents of the buffer address register BAR during writing as a function of the scanned contents of a block availability vector developed by logic (35, 37) from data specifying block availability (33) and buffer storage requirements (25).
Inventors
- 👤 Henry Bardsley Iii
- 👤 Leo John Hasbrouck
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-07 20:08
CPC Classifications
G; G06; G06F; G06F7/00; G06F7/76; G06F7/78; G06F7/785; G06F12/00; G06F12/02; G06F12/08
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
115 words
1 An access control system for a digital data storage device arranged to provide access to fixed block buffer recording areas under the control of a buffer address register in response to applied instructions calling for the writing of records of various lengths extending beyond block boundaries, the system comprising a block usage register arranged to register the number of blocks required by a particular instruction, logic means arranged to develop a block availability vector identifying blocks within said storage device available to meet the requirements specified by said block usage register, and control means for updating said buffer address register as a record writing operation progresses under the control of said block availability vector.
Claim 2
Dependent Claim
115 words
1 An access control system for a digital data storage device arranged to provide access to fixed block buffer recording areas under the control of a buffer address register in response to applied instructions calling for the writing of records of various lengths extending beyond block boundaries, the system comprising a block usage register arranged to register the number of blocks required by a particular instruction, logic means arranged to develop a block availability vector identifying blocks within said storage device available to meet the requirements specified by said block usage register, and control means for updating said buffer address register as a record writing operation progresses under the control of said block availability vector.
Claim 3
Dependent Claim
51 words
2 A system as claimed in Claim 1, for writing variable length count key data formatted character strings into non-contiguous blocks of linearly addressed buffer storage, in which the contents of said block usage requirements are derived from the record count field of the record associated with a particular writing instruction.
Claim 4
Dependent Claim
106 words
3 A system as claimed in Claim 1 or Claim 2 in which said logic means is adapted to form a bit map representation of block availability from a commonly stored buffer block status map, and to complement said bit map logically so that bits representing available block space assume a first Boolean value and said control means is adapted to scan said bit map for the next left-most position of said bit map for the block location whose availability is represented by said first Boolean value, and to alter the buffer address register contents at block boundaries during writing as the available blocks are filled.
Claim 5
Dependent Claim
33 words
4 A system as claimed in Claim 3 in which said control means is further adapted to update the buffer address register contents during reading of the buffer as filled blocks are emptied.
References Cited (Backward Citations)
No citation records indexed.
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