🚀 go-pugleaf

Ralf-Peter Rohbeck wrote:
> 
> Mike Rothenberg wrote:
> >
> > Does anyone know of a device (Switch, MUX, etc.) that would allow
> > two different Unix systems to share the same SCSI tape drive?  I
> > don't want to have to buy 2 expensive tape drives, and I don't
> > want to use NFS.

> Can't you just put the two boxes on the same bus? With good SCSI
> implementations, is should work... I did it between a PC and a VAX
> once and it worked perfectly. Not when I accessed the tape concurrently,
> obviously ;)
> 

 You can share SCSI-tape drives on the same bus if:

  - The drivers support RESERVE/RELEASE SCSI-cmd's. This locks a drive for on
    system, the other gets BUSY status until the owning system sends a RELEASE
    cmd.
  - The controllers on both end don't crash if they are selected by the opposite
    host or if the drivers are configured not to attempt it.
  - Good grounding of all hardware involved is essential.
  - Stay within SCSI length limits.
  - Start with most robust speed settings for SCSI (5 Mb/s, a-sync). If this works
    reliably, try sync. 5 Mb first and perhaps 10 Mb later. If sync. mode doesn't
    improve throughput, stick to a-syn.

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