Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!sdd.hp.com!zaphod.mps.ohio-state.edu!mips!sjsca4!poffen
From: poffen@sj.ate.slb.com (Russ Poffenberger)
Newsgroups: comp.sys.ibm.pc.hardware
Subject: Re: SCSI Board Info Request
Message-ID: <1990Oct16.223855.4793@sj.ate.slb.com>
Date: 16 Oct 90 22:38:55 GMT
References: <9254@orca.wv.tek.com> <1990Oct07.173315.6532@nstar.uucp> <209@xstor.UUCP> <1990Oct13.231715.1548@nstar.uucp>
Reply-To: poffen@sj.ate.slb.com (Russ Poffenberger)
Organization: Schlumberger Technologies, San Jose, CA.
Lines: 22

In article <1990Oct13.231715.1548@nstar.uucp> larry@nstar.uucp (Larry Snyder) writes:
>iverson@xstor.UUCP (Tim Iverson) writes:
>
>>True for Unix, very false for DOS.  The non-intelligent boards are much
>>faster than the 154xB series on a single-threaded OS (e.g. DOS) due to the
>>high overhead on each command: about 2ms per command for the 1542B.  There
>>are also fewer integration problems since you don't have to worry about the
>>1st party DMA getting thrown for a loop by the 386 memory managers.
>
>I had a seagate ST01 here, and it coretested at 700kb/sec - while the
>1542 always comes it about 960kb/sec (these values are of course with
>no cache) under PC-DOS 3.3
>

You will find that the AHA1542 will outperform on transfer rate, but because of
the intelligent "sector mapping" it does, there tends to be a little overhead
when it comes to average access and track to track seek times.

Russ Poffenberger               DOMAIN: poffen@sj.ate.slb.com
Schlumberger Technologies       UUCP:   {uunet,decwrl,amdahl}!sjsca4!poffen
1601 Technology Drive		CIS:	72401,276
San Jose, Ca. 95110             (408)437-5254