Subject: Re: Putting tapes in varblock mode
To: Objects In Mirror Are Closer Than They Appear <>
From: David Gilbert <>
List: current-users
Date: 04/01/1996 19:33:33
>>>>> "Objects" == Objects In Mirror Are Closer Than They Appear <> writes:

>> QIC does tend to have better movement support than 8mm...
Objects> I think you have this backwards.  I have yet to encounter a
Objects> QIC which will support BSR/BSF, while I have yet to encounter
Objects> an 8mm which won't.

	Part of the rigid format of QIC drives (they always have 512
byte blocks even if your driver allows you to access otherwise) is
that they can be used as *random* access devices.  One of the boot
tapes I had for an old HP had a filesystem on the tape (that was used
on the tape and not in memory --- this was around about HpUx 5).  At
the very least, VaxVMS does this too.

	Poor support of QIC drives often starts with the drivers.
UN*X itself supports tape drives very poorly.  We have an 8mm around
that will not BSR or BSF.

	Note that not too many (especially inexpensive) QICs support
random writing (its a matter of having a one track erase head).
However, the format itself was designed with this in mind.


|David Gilbert, PCI, Richmond Hill, Ontario.  | Two things can only be     |
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