Control unit busy queuing
US4546430A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jul 13, 1983 |
| Grant date | Oct 8, 1985 |
| Priority date | — |
| Expiry date | Jul 13, 2003 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG06F13/122
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
In a system wherein a central computer complex is connected through central control modules (CCM) and channel modules (CM) to the control units of peripheral subsystems, a first queue is maintained in a CCM for Start I/O Fast (SIOF) commands waiting to be accepted by the CMs connected thereto. After a CM accepts an SIOF command and passes it on to a control unit, the control unit may return to the CM a busy status which is then passed through to the CCM. The CCM maintains a control unit busy (CUB) queue and an entry is made therein when busy status is returned. When a control unit reports control unit end status to the CCM, the CUB queue is linked to the top of the SIOF so that the CMs may again be informed that the SIOF commands are available. The arrangement avoids two interruptions of the central computer complex to report first that the control unit is busy and then that the control unit is available.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.