[comp.sys.mac] Hard disk interleave

ching@pepsi.amd.com (Mike Ching) (04/04/89)

I am moving a Quantum 280 from a Mac+ to a Mac II and would like to know
if it needs to be reformatted to change the interleave. I think I read
somewhere that drives are formatted with a 3:1 interleave for a Mac+, a
2:1 interleave for a Mac SE and a 1:1 interleave for a Mac II. Is this
correct? Is there a utility similar to Spinrite for MSDOS that can
change the interleave by reading a track, reformatting it and writing
the data back (seems unlikely since SCSI isolates you from the tracks
and sectors)? Does the Apple HD Setup sense the host and format
accordingly or does the interleave have to be set explicitly (I know
there is a magic keypress that opens a dialog)? Thanks for any help. HFS
Backup 3.0 doesn't want to run on my Mac II and matching directories
takes forever on the Plus so an unnecessary backup to 80 disks is
something to be avoided.

Mike Ching

ephraim@think.COM (Ephraim Vishniac) (04/04/89)

In article <25094@amdcad.AMD.COM> ching@pepsi.amd.com (Mike Ching) writes:
>I am moving a Quantum 280 from a Mac+ to a Mac II and would like to
>know if it needs to be reformatted to change the interleave.

Absolutely not.  The Q280 does not have changeable interleaving.
Instead, it has a large enough internal cache that the actual
interleaving makes no difference to the host system.

>I think I read somewhere that drives are formatted with a 3:1
>interleave for a Mac+, a 2:1 interleave for a Mac SE and a 1:1
>interleave for a Mac II. Is this correct?

You probably did read that.  It's a gross generalization.  That is,
it's correct for some particular types of disks with some particular
software, but it's not generally true.

Ephraim Vishniac  /  Internet: ephraim@think.com  / AppleLink: ThinkingCorp
Thinking Machines Corporation / 245 First Street / Cambridge, MA 02142-1214

	"Arlo Guthrie, it seems, has found what he was looking for:
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