> In article <Pine.LNX.3.93.970212111256.5897A-100000@superq.intexp.com>
> Ben Kochie <ben@intexp.com> wrote:
[SNIPPED]
>
> SCSI drives tend to die just the same way as IDE, first you get
> occaisional errors, then frequent errors from the driver about having
> to reset the drive, then it fails to mount. SCSI drives are more
> intelligent and can be more verbose about problems, I remember one
> (Barracuda I think) actually had a set of diagnostic LEDs on it.
> We asked a resident ex-Seagate-engineer disk expert, conversation went
> something like:
>
> "What are these LEDs then ?"
> "Diagnostics"
> "What is it saying ?"
> <pause for closer examination>
> "Drive F**ked"
[SNIPPED]
>
> >Bearing being worn out? Hahahahahah I dont think so. especially the
> >spindle bearings. Hahahaahahahahah
Most all disk drives except for the old full-height Maxtors use sleeve
bearings for the disc assembly. The disc assembly shaft typically runs
through these bearings, pressed into the housing, to a pancake motor.
These bearings are made if sintered metal, impregnated with oil. There
is a patent on a "cup" at the top of the spindle that prevents oil from
wicking up the bearing and spreading, via centrifugal force, out over
the bottom platter.
Manufacturers of cheap drives don't want to pay the license to use this
patented idea. Therefore, this item is eliminated. The result is that
over a period of time, the bearing becomes dry which allows wear. Once
the bearing starts to wear, the disc assembly will wobble, especially
upon startup.
This can happen after the the heads have been moved away from the "crash"
landing zone. This results in a crash in the data area.
The head actuator bearing is subject to another patent. Again, companies
that make cheap drives don't want to pay a license fee to use this patent.
The result is that these bearings also suffer short life.
The same idea works for IDE. If you want to make cheap drives for computers
that are seldom used (like MOST computers), there is a market for these
drives. You would certainly not want to pay a fee to NCR to license their
SCSI technology. Note that SCSI is an open standard, however NCR provides
some chips and licenses to use their technology.
Once you decide to make a high-quality drive for the "Professional"
market, you can charge more for what you produce. This allows you to
use licensed technology to produce a better product. Therefore you
add a SCSI interface, use licensed technology, and build a better product.
Therefore, the very first observation that I stated in this thread:
IDE means cheap.
My professional tour of duty included a Disc Drive manufacturer in
Longmont Colorado. I don't think that my work contributed to their
demise <grin>. However, I do remember quite a bit about these things.
>
> Yes. I thought that most of the SCSI/IDE difference was in the
> interface electronics, and that the actual disk hardware was the same.
You might get the longest life possible out of ANY hard disk drive by
leaving it running <forever>. You have to trade off the cost of doing
this, electric, power supply wear, power supply fan, etc.
Some disk drives must NOT be mounted inverted! Some buildings vibrate
in the wind or when traffic goes by. Disc drives don't like this. You
can put your computer on a thick foam pad to reduce the G-forces imparted
to the drive.
These things can help prevent crashes.
Cheers,
Dick Johnson
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Richard B. Johnson
Project Engineer
Analogic Corporation
Voice : (508) 977-3000 ext. 3754
Fax : (508) 532-6097
Modem : (508) 977-6870
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Email : rjohnson@analogic.com, johnson@analogic.com
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Warning : It's hard to remain at the trailing edge of technology.
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