Data transfer system with disk command verification apparatus
US4148098A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jun 15, 1977 |
| Grant date | Apr 3, 1979 |
| Priority date | — |
| Expiry date | Jun 15, 1997 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG06F3/0673
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
A data processing system includes a disk drive, a disk drive controller, a main memory and a CPU. The main memory has disk command data stored therein in a chain of disk command blocks (DCB's). Each DCB contains a first word pointing to the next DCB in the chain, a second word containing status information and a third word containing command information. A portion of the command word contains a predetermined verification word when the DCB is valid. The CPU includes means for comparing this portion with the predetermined verification word as stored in a constant memory. If the two correspond, the DCB is valid. Each DCB also includes a fourth word pointing to a block of main memory in which header data is stored. Header data defines the address of the recording location of the disk. A fifth word points to a block of main memory in which label data is stored. Label data defines the name and/or number of the file, as well as itself including a pointer to the address location on the disk at which the next page of the file data is stored. A sixth word of the DCB points to a block of main memory in which the associated page of file data is stored. A seventh word specifies the recording lo…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.