US3839704A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Control for channel access to storage hierarchy system
Assignee: International Business Machines Corp
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Filing: 1972-12-06
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Granted: 1974-10-01
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Expires: 1992-12-06
Abstract
Abstract In a storage hierarchy system in which a limited number of blocks of data in a backing store are held in a smaller buffer store, channel requests for access to storage are made to the buffer store. A circuit monitors the channel requests to the buffer store and detects various conditions that indicate that the channel may make a forthcoming request to a block that is held in the backing store but not in the buffer store. When such a request is detected, the circuit produces a dummy request to transfer the block to the buffer store before the actual channel request to this block. The invention reduces the average access time to the store and it reduces the likelihood of a condition called channel overrun that may occur when buffer storage space is not available when requested by the channel.
Inventors
- 👤 D Spencer
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 11:02
CPC Classifications
G; G06; G06F; G06F12/00; G06F12/02; G06F12/08; G06F12/0802; G06F12/0862; G06F2212/00; G06F2212/60; G06F2212/6028
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
133 words
In a data processing system having a buffer store, a backing store, means for controlling the transfer of blocks of data between said stores in response to an address directed to a data block in said backing store but not in said buffer store, and a channel connected to access said buffer store for fetching a control word and for data transfer operations, storage access control apparatus, comprising, means for identifying in a control word fetched bY the channel from said buffer store, an address of a location to be accessed by the channel in the execution of the control word, and means responsive to said address for making a dummy request to the buffer store for initiating a transfer of the associated data block from the backing store to the buffer store.
Claim 2
Dependent Claim
133 words
In a data processing system having a buffer store, a backing store, means for controlling the transfer of blocks of data between said stores in response to an address directed to a data block in said backing store but not in said buffer store, and a channel connected to access said buffer store for fetching a control word and for data transfer operations, storage access control apparatus, comprising, means for identifying in a control word fetched bY the channel from said buffer store, an address of a location to be accessed by the channel in the execution of the control word, and means responsive to said address for making a dummy request to the buffer store for initiating a transfer of the associated data block from the backing store to the buffer store.
Claim 3
Dependent Claim
98 words
The storage access control apparatus of claim 1 wherein, said means for identifying an address in a control word comprises means for producing a first signal identifying that a channel request is for a control word containing an address of a next storage location to be accessed by the channel and producing a second signal identifying that a channel request is for a data transfer operation, and said means for making a dummy request to the buffer store comprises means responsive to said first signal and to the address in said control word for making said dummy request.
Claim 4
Dependent Claim
52 words
The apparatus of claim 2 wherein the data processing system performs operations to bring an addressed block from the backing store to the buffer store and further operations to access the storage unit addressed by the channel and said apparatus further includes means for inhibiting said further operations during a dummy request.
Claim 5
Dependent Claim
38 words
The apparatus of claim 3 wherein said further operations by said data processing system include accessing said buffer store at the location of said address, and said means for inhibiting includes means to inhibit accessing said buffer store.
Claim 6
Dependent Claim
94 words
The apparatus of claim 3 wherein the channel operates according to a program made up of channel command words accessable from said buffer store and the address of a first of said channel command words is held in a channel address word accessable from said buffer store and said means for making a dummy request further includes means for storing the address in the channel address word and means responsive to the completion of the request for the channel address word for making a dummy request to the first of the channel command words.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-09-30 | 1978-04-01 | 1978-10-01 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-09-30 | 1982-04-01 | 1982-10-01 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-09-30 | 1986-04-01 | 1986-10-01 | $7700.00 | Window Closed / Lapsed |