linuxaudio.org

On Tue, 2004-06-01 at 17:42, Malcolm Baldridge wrote:

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> [**WARNING** This is starting to drift off-topic from Linux-Audio ]

> 

	Maybe not.  I think it might come under the heading of "know your

tools".
> > At work I've gone away from SCSI for three reasons - first is cost,

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>

> Yes, in cost per GB, nothing beats IDE.  But for most sizes of drives, the

> extra cost of SCSI isn't that bad.  I've paid  for the last few 36GB

> drives, which is quite reasonable really considering it's a 10,000 RPM drive

> with a large cache and a good warranty.

>

	Wow, $90 is a very good price (although I haven't priced any in a few

years).

> > second is that the speed difference isn't very much anymore,

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>

> One thing I seem to notice is that many SCSI drives don't seem to use the

> full platter in order to keep the heads over the "dense" zones of the media.

> When I examine the transfer rate curves of my Fujitsu MAS 10K RPM drives,

> for example, the difference between inner and outer edge throughput isn't

> anywhere near as great as the difference in performance between the

> inner+outer edges of my WD 200GB drive, for example.

>

> For another thing... I know I can't prove this scientifically, but I have

> ALOT of samples from different manufacturers and time periods over the past

> 15 years.  My SCSI drives last a very long time, and when they've finally

> kicked the bucket (rarely after less than 6 years), I've had ample warning

> [LOG SENSE notifications of soft-retry counts, etc].

>

	Yep, that's for sure.

> In contrast, my IDE drives have failed abruptly and without warning, many

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> times before the warranty was expired.  I have a bucket of such drives,

> which I intend to take the platters out to make attractive and very smooth

> drinks coasters.

>

> The IDE bucket has drives from Seagate, Quantum (the most common being the

> Fireballs, an apt name if I ever heard one), and Maxtor.  Oddly, I have yet

> to throw a dead Western Digital drive into the Drive Bucket of Doom - but

> that could be because I had a bias against the brand for a long time.  But I

> do have many running WDs in current systems as they tend to be the fastest

> drives available for IDE.  I remain offended that they are the only IDE

> drive manufacturer which doesn't include a thermal sensor in their drives.

>

	I've got a pretty big SCSI bucket but we go through hundreds of drives.

> I have functioning SCSI drives in several machines from Seagate, Quantum

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> [dating back to the 1.6" 400MB PD-series, circa 1992 as well as a

> hot-running Grand Prix Wide-Differential 4GB drive circa 1996], IBM, and DEC

> [pre-Quantum acquisition].  This latter drive is a VERY BUSY Squid Proxy

> Cache drive in my home network server [same one which does the audio logging

> from the MERLIN phone system].

> 

	I can get my hands on a really nice 40MB Unisys disk drive.

Unfortunately it's the size of a washing machine (it is removable though

;-)
> > third is that you can't get SCSI in Djibouti (or Honolulu for

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> > that matter).

>

> Really?  That's a bit surprising.

> 

	We actually had to go looking for drives while in Honolulu.  Searched

all over the island and couldn't find a single SCSI drive (this was in

2000).  We finally had to order from the mainland.  We drove over to

Comp USA and bought 4 new 60GB IDE drives for about the cost of shipping

for the SCSI drives and external enclosure.
>

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> > I work with ship and airborne data collection/processing systems.

>

> Those use hard disks?   Fascinating.  I'd have thought the environments were

> too harsh.  Your work sounds interesting, though, Jan.

> 

	If it's not rough you can't tell your on a ship.  It looks like an

office.  The ships are 333 feet (100 meters) long.  The main lab is

about 30x100 feet.  I've been flying gear since the early 80s on P3s and

haven't had a problem with vibration.  What used to fail the most was

monitors.
> > We've had problems getting

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> > SCSI drives anywhere but the states (or Singapore, although I had

> > problems there once - I couldn't find anything old ;-)

>

> Ouch.  That's amazing.

> 

	That was funny.  I needed a 1GB drive for a very old PC and I couldn't

find one anywhere in Singapore.
> > Now we're starting to switch to SATA for the same reason.

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>

> UGH, SATA, at least in this first generation, is a mess.  I've been

> following some of the T13 standards discussions about it, and things don't

> look very pretty there.  All I can suggest is that you validate specific

> drives to controller chipsets for the time being, and watch your cabling

> lengths despite marketing b.s. which claims it can be "very long". Do not

> violate the "grounding rules", and don't run SATA cables outside of

> reasonably shielded environments if they have a great deal of radio emissions.

>

> There are some publicly-accessible discussions of these issues, so this

> isn't just FUD.  See  -- the author, Hale

> Landis, is an involved member of the NCITS T13 [formerly X3T13] committee,

> and has contributed a significant body of work to the ATA standards over the

> years.

>

	Thanks for the link!  That looks really helpful.    Luckily I'm not

having to put these in myself we're just now testing a couple of 3.75TB

Pogo Linux servers for field work.

Jan