Subject: Re: AIC7XXX driver - No Tape support for writing?
To: None <firstname.lastname@example.org, email@example.com>
From: Ross Harvey <firstname.lastname@example.org>
Date: 11/07/1997 12:56:49
> The block device interface to tapes hasn't really ever worked (the semantics
> of implementing it are just too hairy, for one), and probably ought to just
> be removed.
> Jason R. Thorpe email@example.com
It's doubtful for writes, but the block reads worked once, at least.
One night around the end of the last ice age, just for fun I dd'ed a
file system off a pdp-11 unix onto a 125 ips nine track. I mounted the
block device read-only, took a deep breath, and typed "ls".
I was rewarded with several minutes of frantic tape winding and rewinding.
The capstan feeding the vacuum columns could go from 0 to 125 ips in the
space of the inter-record gap. The driver could scan either way for a block.
It was hilarious.
Anyway, "ls", "cat", etc. worked fine, if rather slowly. You could REALLY
SEE the unix buffer cache at work that night. Haven't tried it since.
Ross Harvey Avalon Computer Systems, Inc. firstname.lastname@example.org
Santa Barbara http://www.teraflop.com