*BSD News Article 16317


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From: jcburt@gatsibm.larc.nasa.gov ()
Newsgroups: comp.os.linux,comp.os.386bsd.questions,comp.unix.pc-clone.32bit
Subject: Re: IDE vs SCSI and performance
Date: 20 May 1993 12:25:34 GMT
Organization: NASA Langley Research Center
Lines: 38
Message-ID: <1tftbuINNn9l@rave.larc.nasa.gov>
References: <C72CAw.B47@sugar.NeoSoft.COM> <1993May17.190905.3462@gandalf.ca> <C78rG8.707@rex.uokhsc.edu>
NNTP-Posting-Host: gatsibm.larc.nasa.gov

In article <C78rG8.707@rex.uokhsc.edu> benjamin-goldsteen@uokhsc.edu writes:
>ykhan@gandalf.ca (Yousuf Khan) writes:
>
>>In <C72CAw.B47@sugar.NeoSoft.COM> peter@NeoSoft.com (Peter da Silva) writes:
>
>>>I was talking to a fellow in a computer store the other day, and he was
>>>insisting that he was getting 2.5 MB/s on his IDE drives under AmigaOS,
>>>over twice what he got with SCSI.
>

[...stuff deleted...]

>>>I found that hard to beleive... I suspected that his benchmark was being
>>>messed up by buffering.
>
>>It's likely buffering. There's not a drive in existence that can
>>transfer at that rate without some kind of hardware or software
>>buffering. People like to point out the _potential_ speed of 
>>SCSI hardware, but they all ignore the fact that no SCSI drive
>>even approaches this potential. The potential in an IDE might
>>be lower than a SCSI's potential, but so far they are pretty
>>equal in the real world.
>
>I wouldn't really say that...  Quite a few of the high-end drives are
>actually rather decent.  I have a reference for a MO disk system that
>sustains 12MBytes/second (I have no idea how much this costs...)
>
>Low-end SCSI's versus IDE might be about the same...

I wonder how "local-bus" versus ISA bus fits into this comparison?
I haven't seen many local-bus SCSI controllers, but local-bus IDE
interface cards are becoming more common...so, what *is* the dominating
factor as far as data transfer rates: the disk drive, the 
interface card/controller, the bus...?

John