Path: utzoo!attcan!uunet!seismo!sundc!pitstop!sun!decwrl!labrea!rutgers!bellcore!texbell!killer!dcs!wnp
From: wnp@dcs.UUCP (Wolf N. Paul)
Newsgroups: comp.unix.microport
Subject: Re: Efficient tape I/O with 386/ix; How??
Keywords: streaming tape interactive slow
Message-ID: <251@dcs.UUCP>
Date: 11 Dec 88 04:12:04 GMT
References: <317@focsys.UUCP>
Reply-To: wnp@dcs.UUCP (Wolf N. Paul)
Organization: DCS, Dallas, Texas
Lines: 26

In article <317@focsys.UUCP> larry@focsys.UUCP (Larry Williamson) writes:
 >Streaming tape I/O with 386/ix seems to be rather slow.  The drive
 >is not streaming very well.  It spends most of it's time stopping
 >and starting.  I'm using an Everex Excel 60 with a long controller
 >card. 
 >
 >The command I've used is
 >	find . -print | cpio -ovc >/dev/rmt0
 >

It seems to me that you should be able to achieve the effect of the
"strm" utility on Uport 286 (and other similar utilities, i.e. "stream"
as supplied with the Bell Tech driver, etc.) by using "dd" with a large
block size. You may need to experiment to find out how large a block
size your system will allow, but try something like this:

  find . -print | cpio -ocv | dd of=/dev/rmt0 bs=64k

Then try increasing the "bs" value until you either (a) get no more
performance improvement by increasing, or (b) run out of memory.
(A buffer size of 64k should work even on a 286 system).

-- 
Wolf N. Paul * 3387 Sam Rayburn Run * Carrollton TX 75007 * (214) 306-9101
UUCP:     killer!dcs!wnp                 ESL: 62832882
DOMAIN:   dcs!wnp@killer.dallas.tx.us    TLX: 910-380-0585 EES PLANO UD