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From: j@bonnie.heep.sax.de (J Wunsch)
Newsgroups: comp.periphs.scsi,comp.os.linux.hardware,comp.unix.bsd.freebsd.misc,comp.os.linux.setup
Subject: Re: SCSI PCI host adapter
Date: 30 Aug 1995 15:25:38 +0200
Organization: Private U**x site, Dresden.
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Message-ID: <421osi$76j@bonnie.tcd-dresden.de>
References: <418r3m$9c6@trauma.rn.com> <41sjek$rtu@bonnie.tcd-dresden.de> <1995Aug29.125909.28500@wavehh.hanse.de> <shimon.809740893@ark>
Reply-To: joerg_wunsch@uriah.heep.sax.de
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Xref: euryale.cc.adfa.oz.au comp.periphs.scsi:36916 comp.os.linux.hardware:15106 comp.unix.bsd.freebsd.misc:5630 comp.os.linux.setup:19453
Simon Shapiro <shimon@ssd.intel.com> wrote:
>3. Where is the 8MB/Sec reported in this thread? I saw 1.5 or so.
>> -------Sequential Output-------- ---Sequential Input-- --Random--
>> -Per Char- --Block--- -Rewrite-- -Per Char- --Block--- --Seeks---
>>Machine MB K/sec %CPU K/sec %CPU K/sec %CPU K/sec %CPU K/sec %CPU /sec %CPU
>
>>knight/100MHzPent/asus-ncr/barra2/FreeBSD-2.0.5-RELEASE
>> 140 1543 98.6 5150 40.3 1711 16.5 1808 98.6 5211 26.8 98.1 7.1
^^^^ ^^^^ ^^^^ ^^^^ ^^^^
Only the `per char' figures are slow and suffer from substantial CPU
load. This is natural, it's the o/s overhead (and not the typical
case for disk IO).
This disk gets up to something > 5 MB/s (block IO). It's actually
already one of the faster species. :)
AFAIK, you won't find a disk that could keep up to 8 MB/s. That
figure refered to the *bus throughput*, and since no disk can load the
bus up to that amount, it requires two or more disks in order to see
this. Given that the raw transfer speed is 10 MB/s, the figure 8
characterizes the quality of the driver and controller to arbitrate
the bus.
--
cheers, J"org private: joerg_wunsch@uriah.heep.sax.de
http://www.sax.de/~joerg/
Never trust an operating system you don't have sources for. ;-)