Date: Mon, 10 Apr 2006 10:02:34 -0400 From: Christian Lopez de Castilla Wagner <lopisaur@gmail.com> To: "Matthew D. Fuller" <fullermd@over-yonder.net> Cc: freebsd-stable@freebsd.org, "Chris H." <fbsd@1command.com> Subject: Re: Pros and Cons of amd64 (versus i386). Message-ID: <1144677754.28282.5.camel@hellion.clcw> In-Reply-To: <20060409182254.GL41551@over-yonder.net> References: <CBC0AAB4-EC80-44C8-BCCE-010DE99D4BC0@khera.org> <E1FRVcq-0004pJ-4c@dilbert.firstcallgroup.co.uk> <20060406192950.GE700@turion.vk2pj.dyndns.org> <20060408203233.K67402@woozle.rinet.ru> <20060408212421.GB720@turion.vk2pj.dyndns.org> <20060408160304.ek1xxodrkok4gw4g@webmail.1command.com> <44384EB8.8090803@samsco.org> <20060409182254.GL41551@over-yonder.net>
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On Sun, 2006-04-09 at 13:22 -0500, Matthew D. Fuller wrote:
> On Sat, Apr 08, 2006 at 06:00:56PM -0600 I heard the voice of
> Scott Long, and lo! it spake thus:
> >
> > Modern disks (I don't know how to define a cutoff to this term,
> > unfortunately) definitely put more bits onto the outer rim of the
> > platter than the inner rim.
>
> Pretty much any disk you'd currently find, I'd say.
>
> diskinfo -t won't run through on my 4 or 2 gigs ("disk too small for
> test" :), but on my 9 gigger:
>
> Transfer rates:
> outside: 102400 kbytes in 5.215159 sec = 19635 kbytes/sec
> middle: 102400 kbytes in 6.268067 sec = 16337 kbytes/sec
> inside: 102400 kbytes in 8.237962 sec = 12430 kbytes/sec
>
> da4 at ahc2 bus 0 target 5 lun 0
> da4: <IBM DNES-309170W SAH0> Fixed Direct Access SCSI-3 device
> da4: 40.000MB/s transfers (20.000MHz, offset 31, 16bit), Tagged Queueing Enabled
> da4: 8748MB (17916240 512 byte sectors: 255H 63S/T 1115C)
>
>
Just for comparison:
root@hellion# diskinfo -t ad1
ad1
512 # sectorsize
61492838400 # mediasize in bytes (57G)
120103200 # mediasize in sectors
119150 # Cylinders according to firmware.
16 # Heads according to firmware.
63 # Sectors according to firmware.
Seek times:
Full stroke: 250 iter in 5.650173 sec = 22.601 msec
Half stroke: 250 iter in 4.581880 sec = 18.328 msec
Quarter stroke: 500 iter in 7.510191 sec = 15.020 msec
Short forward: 400 iter in 3.556557 sec = 8.891 msec
Short backward: 400 iter in 3.294277 sec = 8.236 msec
Seq outer: 2048 iter in 0.285684 sec = 0.139 msec
Seq inner: 2048 iter in 0.288960 sec = 0.141 msec
Transfer rates:
outside: 102400 kbytes in 1.896157 sec = 54004
kbytes/sec
middle: 102400 kbytes in 2.297042 sec = 44579
kbytes/sec
inside: 102400 kbytes in 3.853005 sec = 26577
kbytes/sec
ad1: 58644MB <IC35L060AVV207 0 V22OA63A> at ata0-slave UDMA100
As you can see, the outside is more than twice as fast in this case.
Just a guess, since both are IBM disks: You're using a
Workstation/Server disk, which probably performs in a more balanced way
across the platter, while this (consumer disk) is not
performance-oriented. Maybe SCSI and IDE devices are not as similar as
we all thought?
--
Christian Lopez de Castilla Wagner
lopisaur@gmail.com
lopisaur@acelerate.com
(+591-705)98290
http://lopisaur.googlepages.com
http://lopisaur.blogspot.com
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