> 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                                       thorpej@nas.nasa.gov

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.		  ross@teraflop.com
		Santa Barbara	 		    http://www.teraflop.com