From: Baldwin_James at domain emc.com
Date: Mon 18 Jun 2001 - 12:39:44 IST
HEH! God, I better get my secretary to proof-read my mails infuture to
advoid unneccessary litagation!(as is now!) ;)
I am just stating that nominally external devices can be slower than
internal devices, due to extended latency, or if the bus has to go through
another 3rd party logic controller on the ext. device, etc...
YES, the main aim of LVD was to go beyond the 3 Foot limit of UW
Cable...towards 12M max cable length and from 5v to 3.3 + 15v
Of course a good shielded cable will keep the interface rate up...
> Even external, a 10k RPM drive should be a good bit (15% ?)
> better...seek time especially.
What application are you using for the ext. drive?
I'd say being an ext. drive, nothing which requires critical superior
latency or transfer speed.
Even at that....advertising make us believe a need for 'fantasic'
controllers which can do a mind-spliffing 160 Mb/Sec...why(when using a
single device - I am proof reading here)? The fastest market-available
drive, the 15k Segate Cheetah, can still only deliver about 26 MB/Sec
sustained transfer rate.....the Peak bus speed only comes into effect when
you read Disk Cache..... Moving parts will always be the slowest part of a
computer....Solid-state storage would make things alot of more
From: John P. Looney [mailto:john at domain antefacto.com]
Sent: Monday, June 18, 2001 11:52 AM
To: ilug at domain linux.ie
Subject: Re: [ILUG] External SCSI Hard Drive
On Mon, Jun 18, 2001 at 06:32:50AM -0400, Baldwin_James at domain emc.com mentioned:
> Look here...this is basically what you are looking at...note that the
> firewire Drives(IDE) are much cheaper than SCSI...
> Also, remember that you wont really feel the benefit of a 10k LVD SCSI
> over a 7.2k IDE drive on an external connector...
I thought the whole point of LVD was that you could run it over longer
Even external, a 10k RPM drive should be a good bit (15% ?)
better...seek time especially.
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