Extension of data block capability in a data transfer channel
US5539918A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | May 26, 1995 |
| Grant date | Jul 23, 1996 |
| Priority date | — |
| Expiry date | May 26, 2015 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG06F13/385
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
An adaptive data transfer channel providing means for a data management access method (AM) to define the channel subsystem data block transfer size and to transfer an extended data block (EDB) by a single channel transfer command to avoid repeated channel command word (CCW) command decode and status presentation operations. The adaptive scheme of this invention is transparent to the user and downwardly compatible with existing data record storage formats because it is independent of the user application program. The host software in the central processing complex (CPC) tests the peripheral data storage device (PDSD) to ensure compatibility with the EDB CCWs before selecting the channel program (CP) to be used for data block transfer in the subchannel. In the EDB format, the PDSD microcode permits the accumulation of logical data blocks (LDBs) from storage to form a single large EDB before transfer to the CPC responsive to a single transfer command. Conversely, the CPC can transfer a single EDB to the PDSD where it is parsed to form data records in an existing data record storage format, thus ensuring complete downward compatibility with existing data record storage formats.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.