Hung Tran Dinh

US Patent:

6151649, Nov 21, 2000

Filed:

Dec 13, 1998

Appl. No.:

9/211207

Inventors:

Thomas Sing-Kiat Liong - San Jose CA
Hung Dinh - Union City CA

Assignee:

International Business Machines Corporation - Armonk NY

International Classification:

G06F 1300
G06F 1340

US Classification:

710126

Abstract:

System, apparatus, arid method for automatically detecting power-down, disconnection, or other failure of a SCSI bus connected device and isolating the SCSI node from the rest of the computer environment. Sensing a problem at the device node and substituting a buss termination circuit for the termination that had been provided by the device. Sensing the reconnection or power-up of a device at a SCSI bus mode and simultaneously reconnects the device's own terminator and removes the termination provided at disconnection. Particularly useful in clustered computer environments, such as for example, for data base server systems in which a plurality of server computers share a common data base comprised of one or more disk drives on a SCSI bus. Permits any of the servers to be disconnected from the clusters system or network and be repaired or replaced without powering-down or otherwise disabling the entire system or other devices on the system. One embodiment provides a switching circuit including a first input/output port having a plurality of first, port terminals, a second input/output port having a plurality of second port terminals, a terminator circuit having predetermined electrical characteristics, a reference voltage generator,.