Messages in this thread | | | Date | Fri, 01 Jan 1999 10:29:10 +1100 | From | Dancer <> | Subject | Re: Drunken mumblings [OFFTROPIC] |
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"Richard B. Johnson" wrote: > > On Wed, 30 Dec 1998, John R. Lenton wrote: > [SNIPPED] > > > > Can a SCSI cable be used to connect computers? I mean, can a > > computer be daisychained with say a hard disk? In theory at > > least? Using a special card? > > A SCSI disk (or any SCSI device) can be "shared" by other masters on > the SCSI bus. The master only has to win arbitration (it's done by the > chip), and it can access any device that wants to be accessed. I use > "want" here in a particular way. A SCSI Host controller, and its driver > software, generally doesn't "want" some other SCSI master telling it what > to do. > > Therefore, communications with a device such as a disk, by two separate > computers, is not a problem. You can, in fact, use a common hard disk > even to boot two different machines. The problems come if one or more of > the machines tries to write to the disk.
This sort of setup (two machines sharing one or more drives via a SCSI chain) was not outrageously uncommon, back in the mid-80's. You've got to be willing to have zero read/write buffering, and have your filesystem make a few concessions. IE: Performance degrades.
D
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