Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!usc!zaphod.mps.ohio-state.edu!mips!daver!bungi.com!news
Newsgroups: comp.sys.nsc.32k
Subject: Re: Sanity Check ...
Message-ID: <9009221615.AA05500@manatee.UUCP>
Date: 22 Sep 90 20:15:40 GMT
Sender: news@daver.bungi.com
Lines: 20
Approved: news@daver.bungi.com

An addition thought I forgot to include in my previous message today.

>> By the way, the hold-off at least wrt tape reads, appears at the 
>> very beginning of each 'datain' phase and during streaming breaks.

> I would have hoped that the tape would only interrupt (via scsi) when the
> data was 'really' ready to be read. Is this an embedded controller type with
> a reasonable local buffer or a 'dumb' external controller?

Standing back, its not clear to me at the moment that efficient use of
interrupts will in this instance increase disk-to-tape or tape-to-disk 
throughput under Minix.  With or without interrupts, the FS process 
will remain blocked until the device driver task completes.  Of course, 
avoiding prolonged assertion of /nrdy or busy waits by prudent use of 
interrupts will permit other scheduled processes to run in the mean time.

best regards,
johnc

--