# US 5,710,909 A · Data compression utilization method and apparatus for computer main store

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- Number: US 5,710,909 A
- Document ID: US5710909A
- Status: Granted
- Kind: A
- Application number: 08/590,134
- Filed: 1996-01-23
- Granted: 1998-01-20
- Earliest claimed: 1996-01-23
- Assignees: International Business Machines Corporation
- Inventors: Jeffrey Douglas Brown; Scott Douglas Clark; Michael Joseph Corrigan; Kent Harold Haselhorst; Larry Wayne Loen
- Web page: https://patentgrep.com/patent/US5710909A

## CPC

- G06F 12/023: {Free address space management}
- G06F 12/08: in hierarchically structured memory systems, e.g. virtual memory systems
- G06F 2212/401: Compressed data
- G06F: ELECTRIC DIGITAL DATA PROCESSING (computer systems based on specific computational models G06N)

## Abstract

A data compression utilization method and apparatus are provided for a computer main store. An amount of unused memory in the computer system main store is dynamically calculated and compared with a plurality of predefined threshold values. One interrupt of a plurality of predefined interrupts is selectively generated responsive to the compared values. Then the usage of the computer system main store is adjusted responsive to the generated interrupt.

## Claims

### Claim 1

An apparatus for utilizing data compression in a computer system main store comprising:
means for dynamically calculating an amount of unused memory in the computer system main store and for comparing the calculated amount with a plurality of predefined threshold values;
means responsive to said compared values for selectively generating one interrupt of a plurality of predefined interrupts; and
means responsive to said generated interrupt for adjusting the usage of the computer system main store.

### Claim 2 (depends on 1)

An apparatus as recited in claim 1 wherein said plurality of predefined threshold values include an urgent memory overflow threshold value, a memory overflow threshold value, and a memory underflow threshold value.

### Claim 3 (depends on 1)

An apparatus as recited in claim 1 wherein said plurality of predefined interrupts include an urgent memory overflow interrupt, a memory overflow interrupt, and a memory underflow interrupt.

### Claim 4 (depends on 1)

An apparatus as recited in claim 1 wherein said means responsive to said generated interrupt for adjusting the usage of the computer system main store include means responsive to a predefined memory overflow interrupt for deallocating memory pages to lower the usage of the computer system main store.

### Claim 5 (depends on 1)

An apparatus as recited in claim 1 wherein said means responsive to said generated interrupt for adjusting the usage of the computer system main store include means responsive to a predefined memory underflow interrupt for reallocating memory pages to increase the usage of the computer system main store.

### Claim 6 (depends on 1)

An apparatus as recited in claim 1 wherein said means responsive to said generated interrupt for adjusting the usage of the computer system main store include means responsive to a predefined urgent memory overflow interrupt for deallocating memory pages to lower the usage of the computer system main store and further includes means for suspending selected tasks until said generated urgent memory overflow interrupt is cleared.

### Claim 7

A method for utilizing data compression in a computer system main store, said method comprising the steps of:
dynamically calculating an amount of unused memory in the computer system main store and comparing the calculated amount with a plurality of predefined threshold values;
selectively generating one interrupt of a plurality of predefined interrupts responsive to said compared values; and
adjusting the usage of the computer system main store responsive to said generated interrupt.

### Claim 8 (depends on 7)

A method for utilizing data compression in a computer system main store as recited in claim 7 wherein said step of adjusting the usage of the computer system main store responsive to said generated interrupt includes the steps of deallocating memory pages to lower the usage of the computer system main store responsive to a predefined memory overflow interrupt.

### Claim 9 (depends on 7)

A method for utilizing data compression in a computer system main store as recited in claim 7 wherein said step of adjusting the usage of the computer system main store responsive to said generated interrupt includes the steps of reallocating memory pages to increase the usage of the computer system main store responsive to a predefined memory underflow interrupt.

### Claim 10 (depends on 7)

A method for utilizing data compression in a computer system main store as recited in claim 7 wherein said step of adjusting the usage of the computer system main store responsive to said generated interrupt includes the steps of deallocating memory pages to lower the usage of the computer system main store responsive to a predefined urgent memory overflow interrupt and suspending selected tasks until said generated urgent memory overflow interrupt is cleared.