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Algorithm for the Management of Core Storage

IP.com Disclosure Number: IPCOM000079537D
Original Publication Date: 1973-Jul-01
Included in the Prior Art Database: 2005-Feb-26
Document File: 2 page(s) / 40K

Publishing Venue

IBM

Related People

Nagda, JM: AUTHOR [+2]

Abstract

Shown is a program routine for allocating storage space in a high-speed buffer and for staging data between a lower speed storage device and the buffer. In this environment, the size of the program module to be moved from low-speed storage to the high-speed buffer is not predefined. This is accomplished by a routine that frees up an area in the high-speed memory corresponding to space consumed by modules stored in the high-speed buffer, which have a usage value below a predetermined threshold. Each time space is required to bring in a new module, the threshold is recalculated. Any module with a usage value falling below the threshold is marked as being available to be overwritten; i.e., its space in the high-speed buffer is available.

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Algorithm for the Management of Core Storage

Shown is a program routine for allocating storage space in a high-speed buffer and for staging data between a lower speed storage device and the buffer. In this environment, the size of the program module to be moved from low-speed storage to the high-speed buffer is not predefined. This is accomplished by a routine that frees up an area in the high-speed memory corresponding to space consumed by modules stored in the high-speed buffer, which have a usage value below a predetermined threshold. Each time space is required to bring in a new module, the threshold is recalculated. Any module with a usage value falling below the threshold is marked as being available to be overwritten; i.e., its space in the high-speed buffer is available.

Operation of the program begins when program control calls for a module (step 2). As the module called is accessed, a total counter TCTR is incremented by one (step 3). The total counter keeps a running count of the quantity of total accesses to all modules, whether the given module accessed happens to be in the low-speed storage device or in the high-speed buffer.

Next, the routine checks to see if the module is in low-speed storage or is in the-high speed buffer (step 4). If the module is already in the buffer, then its module usage value or module count MCTR is updated. The calculation for updating is performed by step 5 and consists of averaging the previous module value, carried in a module table in the high-speed buffer, with the present total counter value. The program routine then exits.

If the module is not in the high-speed buffer, as determined by step 4, ...