Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!tut.cis.ohio-state.edu!bloom-beacon!spdcc!dyer
From: dyer@spdcc.COM (Steve Dyer)
Newsgroups: comp.sys.ibm.pc.rt
Subject: Re: BSD Unix on 6150-135?
Message-ID: <2681@spdcc.SPDCC.COM>
Date: 28 Feb 89 16:24:39 GMT
References: <1966@nmtsun.nmt.edu> <28304@bu-cs.BU.EDU> <496@Portia.Stanford.EDU> <2852@stpstn.UUCP>
Reply-To: dyer@ursa-major.spdcc.COM (Steve Dyer)
Organization: S.P. Dyer Computer Consulting, Cambridge MA
Lines: 20

In article <2852@stpstn.UUCP> aad@stepstone.com writes:
>>	- ACIS seems to have a better driver for the streaming tape
>>	  drive.  It'll keep the drive streaming on its own.
>I remember 4.2 ACIS as being pretty wretched on the tape -- is 4.3
>better?  It used to take me 45 minutes to do a tar cf of a Scribe
>distribution (5 or 6 meg) onto a cartridge.

You have to use the block device to write the tape and the raw device
to read the tape to get the proper (i.e. reasonably fast) behavior.
I've never timed it, but writing to the block device is MUCH faster
than writing to the raw device.  You get some degree of asynchronicity
with the block device, presumably enough to keep it streaming a greater
percentage of the time (it ain't perfect.)  Presumably the concept
of a "tape record" is artificial on these cartridge tapes (which is
why this isn't a solution for reel-to-reel.)

-- 
Steve Dyer
dyer@ursa-major.spdcc.com aka {ima,harvard,rayssd,linus,m2c}!spdcc!dyer
dyer@arktouros.mit.edu