🚀 go-pugleaf

Multitasking means there's a signigicant portion of operation swapping
between mutiple devices. Multitasking across 2 or 3 devices once in a while
is not considered multitasking in this sence, thus can't justify the extrs
investment in SCSI, both controller and hard drives.
Ok, I saw there were quite a few replied to my post in this issue, I'll try
to make my points clear once for good.

1. The original question was "Is it possible to get 16MB/sec", the answer is
no, no Hard drive can sustain that. Neither EIDE nor SCSI.
2. My previous poster claims he can " have real 40MB/sec " though his scsi
card. That claim is ignorant bragging.
3. Scsi is slightly better in performance, but agian, the performance lead
doesn't justify the price.
4. UDMA brings down the cpu load close to Scsi level.
5. SCSI's are usually not stable running @ 83MHz bus. Those claim their
UW2940 stable could have a better than average card, or more likely, their
systems are running asynchronize PCI bus, i.e. their pci stays at 33MHz, not
41.5. I won't even risk oc SCSI @ 83MHz bus, cuz the reason to choose scsi
is for reliability and important work in the first place.
6. SCSI has been losing ground to IDE for at least five years, and will
continue if they can't be cost effective.
7. For most home users which have 1 or 2 hd, 1 cd, no cdr, no scanner, no
jaz etc, there is ABSOLUTELY no reason to think about SCSI for now. But if
you already have a scsi card, consider scsi cd-rom instead of hard drive,
cuz fast IDE cd-roms are really cpu sucker.
8. My experience? I am usnig IBM Deskstar3, Quantum 6.4 STA , Seagate 9GB UW
Scsi drive w/Adaptec 2940 UW card. If I am going to buy another hd for home
pc for now, IBM udma for sure.

John Kotches wrote in message <34899966.B65AB640@pobox.com>...
>Ron Reaugh wrote:
>>
>> Jason <jneus@prodigy.net> wrote in article
>> <34824337.CAA79322@prodigy.net>...
>> >
>> >
>> > jake@binghamton wrote:
>> >
>> > > The physical limit for transfer rate of today's HD is about
>> > > 15mb/sec. No HD can sustain a rate higher than that.
>> > > 33MB/sec of UDMA and 40MB/sec of UWSCSI are theoretical limits.
>> > > Do your home work and don't brag your scsi here.
>> > > It's a waste of money if not used as multitasking server.
>
>Actually Jake, the minute you start multitasking across more than 2
>devices it isn't a waste of money.
>
>
>
>> > Are we a little hostile?    I don't have a degree in computer
>> > science, but let me share what my impressions about SCSI are.  I
>> > will agree that most drives (EIDE vs. SCSI) are fairly equal in
>> > real world performance.  However, I was under the impression that
>> > since SCSI interfaces only use a fraction of the CPU cycles that
>> > IDE interfaces use, SCSI devices are preferable when doing
>> > CPU intensive operations, as the controller handles most of the work
>> > without the CPU's help.
>
>
>Excellent synopsis of the beauty of Busmastering controllers of
>any type :-)
>
>
>> Busmastering EIDE levels that playing field.
>
>Ron,
>
>You keep making these claims about how great EIDE is.  Would you
>mind pointing us towards some benchmarks which validate your
>claims?  As it is, you're statements are just words on the screen
>with no backup to establish validity to them.
>
>>
>> Regards,
>>
>> Ron Reaugh
>
>--
>I've munged my address to help foil those
>insiduous spammer-type persons.  Remove the
>_s to get my real address.
>
>jkotches@_pobox_.com