Data compression method and apparatus
US4682150A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Dec 9, 1985 |
| Grant date | Jul 21, 1987 |
| Priority date | — |
| Expiry date | Dec 9, 2005 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG07C1/10
- WIPO fieldControl
- WIPO sectorInstruments
Abstract
A system and apparatus for compressing redundant and non-redundant binary data generated as part of an operation of a time and attendance terminal in which the data represents the time an employee is present during working hours. The first data entry includes the date and the time the employee operates the terminal together with other data identifying the employee which is stored in a circular buffer. The time of day data includes the hour and the minutes of the keyboard operation. Subsequent data entries include redundant data such as the date and the hour of the terminal operation which may not change and non-redundant data such as the minutes that pertain to the terminal operation together with data identifying the operator. After the redundant and non-redundant data of the first data entry are stored, only the non-redundant data of each subsequent data entry is stored. Upon reading out the non-redundant data from the buffer, a pointer which includes the redundant data such as the date and the hour of the first data entry is added to the non-redundant data read. If the date and/or hour changes, such changed data is stored in the buffer and is transferred to the pointer as the da…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.