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Path: sserve!manuel.anu.edu.au!munnari.oz.au!sgiblab!darwin.sura.net!mojo.eng.umd.edu!pandora.pix.com!stripes
From: stripes@pix.com (Josh Osborne)
Subject: Re: ISA is faster than EISA ? (Was: Re: DOS and 386BSD (and NT and OS2))
Message-ID: <BwIwu4.Mx6@pix.com>
Sender: news@pix.com (The News Subsystem)
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Organization: Pix Technologies -- The company with no adult supervision
References: <1992Oct16.175743.19250@fcom.cc.utah.edu> <1992Oct21.160231.6516@ntuix.ntu.ac.sg> <1992Oct22.093459.13824@autelca.ascom.ch>
Date: Thu, 22 Oct 1992 12:46:51 GMT
Lines: 31
In article <1992Oct22.093459.13824@autelca.ascom.ch> nbladt@autelca.ascom.ch (Norbert Bladt) writes:
[...]
>> SCSI 2 looks fast because it has 32-bit bus between controllers,
>>but it still has to communicate via ISA 16-bit bus, even if you have
>>the 32-bit EISA bus, the speed of the EISA bus may not match with the speed of
>>the SCSI-2. ISA bus is still much faster than any hard-disk controller.
>You say, that the EISA bus is too slow for SCSI-2, but the ISA bus is still
>faster than any hard-disk controller. It indirectly follows:
>
>You say that the (16-bit 8Mhz) ISA bus IS FASTER than EISA bus ?
Nope. What he means is "While the SCSI(-2) bus is faster then the ISA bus
(and the SCSI-2 bus may be faster then the EISA bus), the disks that cost less
then your house are far slower then the SCSI bus, and in fact are slower then
the ISA bus.".
>This must be wrong !
>The DMA rate on the ISA bus is about 5 (or 5.7) MB/sec. while on the EISA
>bus it is (up to) 33MB/sec. Quite a difference in my opinion.
You would be lucky to find a disk that did more then 1M/second.
Of corse, since the video is also on that bus, and video tends to suck
tons of bandwidth, having an EISA bus may make your disks seem faster
because there is more bandwidth to share...
[...]
--
stripes@pix.com "Security for Unix is like
Josh_Osborne@Real_World,The Multitasking for MS-DOS"
"The dyslexic porgramer" - Kevin Lockwood
We all agree on the necessity of compromise. We just can't agree on
when it's necessary to compromise. - Larry Wall