news@crash.cts.com (Usenet News) (07/16/89)
I posted the information that Thad left about his Seagate "stiction" woes and
here is one persons reply...
Sub: Re: Seagates and other HD's
To: Bob Lindabury (#145)
From: Dr. Ken (#1)
Date: 07/14/89 18:58:31
Bob - Before you lean on the panic button, I would try to find out if Seagate
has remedied the manufacturing problem which occurred 15+ months ago (since it
manifests itself after 15 months, it was most likely a problem 15 to 20 or more
months ago). I would be surprised (shocked might be a better word) if they
haven't already resolved it.
Thanks for sharing that info with us. Funny, but with all the hundreds
of thousands of Seagate owners out there, I never heard of this problem before,
especially if its a wide-spread as that single author leads us to believe, I
wonder why. Anyway, I wouldn't worry about it until you have a problem - IF
you have a problem. If there are 1,000 such bad units out there and there are
a total of 1 million Seagate drives on the market, that's only 0.1%, which is a
VERY small error rate (QC problem) by many (most?) manufacturing standards.
Compare that number to 20%-25% problem rate with CMS (power supply problems
account for almost all of those returned items) or 30+% for Chinook. When I
had my problems with the CMS drive, the first problem was the power supply went
out, the 2nd drive's problem was they simply returned to me a bad, rebuilt
drive per se.
I must say that, being a Biologist with a VERY HEAVY chemistry
background, I find it almost impossible to believe the statements regarding
people using a cloth to put down a 1-2 molecule thick layer - that is pure
balderdash, the product of an overly-active embellishment of a story. And I
find it equally difficult to believe that a 5-6 molecule layer of lubricant can
"glue" anything to anything, especially a head which, in molecular
measurements, flies well over the surface at quite a distance. This is NOT to
say the story isn't basically true, but these specific remarks about molecules
doesn't ring true. Maybe the author confused "molecules" with "microns" or
some such measurement.
Despite the embellishments, its good to get such comments - consumers
should have all information available BEFORE purchasing, and they can decide
what to believe and what not to believe and what chances they want to take.
Ken
P.S.
Upon rereading my above comments, I want to make sure that everyone
appreciates the fact that I did NOT quote "1,000 bad units" and "1 millions
units on the market" as numerical facts - rather, I simply plucked those
numbers out of thin air (the million number is in the ballpark according to an
article I read on hard drives a few months back) and were meant only to
illustrate how "a large number of faulty drives" can be a comparatively minor
manufacturing QC problem (to the company - if you're one of the consumers who
received a defective unit, it is quite a BIG problem for you!).
_________________________ Pro-Graphics 201/469-0049 __________________________
UUCP: crash!pro-graphics!bobl | ProLine: bobl@pro-graphics
InterNet: crash!bobl@pro-graphics.cts.com | CServe: 70347,2344
ARPA/DDN: crash!pro-graphics!bobl@nosc.mil | AppleLink: Graphics3D
___________ ____________
Raven Enterprises - 25 Raven Ave. Piscataway, NJ 08854news@crash.cts.com (Usenet News) (07/16/89)
Here is anothers comments on Thad's "stiction" problem...
Sub: Re: Seagates and other HD's
To: all
From: Phil Hackett (#292)
Date: 07/15/89 04:55:07
Let me jump in here: I worked at a plant where we plated magnetic coatings onto
platters and drums for computer drives. The company I worked for also built the
heads that were used. I cannot believe Seagate would have people manually
applying a "lubricant" onto the disks with "rags". We used to plated coatings
as thin as .000005" (that's 5 millionths of an inch!), this was less than the
surface finish RMS (roughness measurements) and ANY other substance visable on
the surface was grounds for rejection (the disk). Most of the plated media
didn't require "lubrication" (one exception was the drums used in the Minuteman
Missle system....it had a Rhodium top plate) but when they do it's generally
hard Chrome plated about 25 microinches...anyways, what I have to say is just a
tiny bit of dust in ANY type of wiping material will scratch a platter
something fierce...I know, I've scraped a few in my time.....
A tidbit: at one time Telefunken had us plate 3 48" disks. We had to set up an
entire plating line just to do them! These things were massive! They were about
an inch thick and were a B**CH to handle. The disk substrate cost about
$3500/ea so we were VERY careful with them!
Phil
_________________________ Pro-Graphics 201/469-0049 __________________________
UUCP: crash!pro-graphics!bobl | ProLine: bobl@pro-graphics
InterNet: crash!bobl@pro-graphics.cts.com | CServe: 70347,2344
ARPA/DDN: crash!pro-graphics!bobl@nosc.mil | AppleLink: Graphics3D
___________ ____________
Raven Enterprises - 25 Raven Ave. Piscataway, NJ 08854thad@cup.portal.com (Thad P Floryan) (07/17/89)
Sigh. Why do I get the impression our "anonymous" poster "news@crash.cts.com (Usenet News)" is ignoring the gist of the recent discussion concerning "stiction" and the problems people ARE experiencing with their hard disk drives? In light of the Apple service bulletin reprint by Computer Plus in CONNECTION stating problems with Apple HDs in "the serial number range 335507 to 1023016, inclusive" implying 687,509 stiction-plagued HDs (which I posted several days ago), it's clear the problem IS widespread. "Dr. Ken"'s stated area of expertise is that of a "being a Biologist with a VERY HEAVY chemistry background". I fail to see what relevance this has on the current discussion. MANY of the chemicals used in the computer and the electronics industry are inorganic, NOT organic-based (ref: "Biologist"). Though it's been nearly 22 years, my work experience assisting the building of a GaAs (Gallium Arsenide) Microwave Integrated Circuit Lab facility (at the GTE Electronics Defense Labs) attests I'm not a dilettante in these matters. As stated independently by the three (local) HD repair companies, the problem of stiction is "common and widespread" and is known in the trade as "white worms" because that's how the problem reveals itself when examined under a microscope. The excess lubricant is "wiped" by the HD heads into the outer and inner zones of a HD's platter; it's the excess material in the inner zones (the "PARK" area) that causes the stiction problem when a drive is powered down. My explanation of the circumstances causing the problem was paraphrased (and NOT embellished!) from the information given me by the HD repair companies. With reference to "Dr. Ken"'s statement: "And I find it equally difficult to believe that a 5-6 molecule layer of lubricant can "glue" anything to anything, especially a head which, in molecular measurements, flies well over the surface at quite a distance." Either he's not being presented the COMPLETE text of my earlier postings (by our "anonymous" poster), or he's not aware the problem manifests itself when the heads are at REST and "in contact" with the platter surface. A simple experiment that ANYONE can do to see the effects of "stiction" requires but two small flat glass squares and a drop of water: 1. Press the two flat glass plates together. Slide them around, and separate them by prying them apart. Easy. 2. With the two glass plates still separated, apply the water drop to the "inner" surface of one of the plates. 3. Again press the two flat glass plates together. Just TRY to separate the two plates. This is the efficacy of "stiction", and what I loosely termed "GLUED" together (with respect to the HD heads and the platters). Simply EXAMINE the surfaces of a modern HD's platters and the "contact" surfaces of the HD's head sleds. The surfaces of both the platter and the head, combined with the excess lubricant, mimic precisely the condition and the effects of the simple experiment I described above. Again, "stiction." And now, to bring everyone up to date with modern chemistry and its marvels, and though I'm fully aware this is NOT the chemical lubricant used on HD platters, I would like to cite just ONE lubricant (of many I use) whose mono-molecular layering (and recommended application with a "rag") is integral and fundamental to its efficient use: Cramolin (tm). Cramolin is produced by Caig Laboratories, Inc.; 1175-O Industrial Avenue; Escondido, CA 92025-0051; ph: 619/743-7143. The Cramolin product is popularly known as an "anti-oxidant lubricant" and is used on precision IC sockets, gold plated connectors, switch contact points, coin-silver collector rings in space gyroscopes, avionics, test labs, marine electronics, high-end audio equipment, etc. by companies such as: American Airlines, American Broadcasting Co., Ampex Co., AT&T, Audio Research Corp., Bell & Howell, Bell Telephone Labs, Bendix Corp., Boing Co., Capitol Records, Cherry Electrical Products, Continental Telephone, Cutler Hammer Inc., Dolby Labs, Dow Chemical, E.I. DuPont de Nemours, Exxon Co., General Dynamics, General Electric Co., General Motors Corp., Grumman Aerospace Corp., GTE Corp., Hazeltine Corp., Hewlett-Packard, Hughes Aircraft Co., IBM Corp., ITT Corp., Jet Propulsion Labs, Litton Industries, McDonnell Douglas Corp., McIntosh Labs, 3M, Magnavox Co., Motorola Inc., Nakamichi Corp., Pratt & Whitney Aircraft, RCA Corp., Rockwell International, Singer, Sperry Gyroscope Div., Sylvania, Texas Instruments, TRW, Inc., US Defense Department, Western Electric Co., Inc., Yamaha Corp., and others. From Caig Laboratories' Service Bulletin SB-4, reprinted without permission: "Suggested methods of application for Cramolin Red/Blue fluid 1. take a clean linen cloth -- soak approximately a 4"x4" square cloth -- and spray until it gets a light pink color (R) or light blue (B). First test to see if cloth has been saturated with enough Cramolin Fluid by pressing a corner of the cloth against a clean dry glass specimen slide. Look at the spot on the glass under reflected light. You should be able to see a small oily looking spot. If the spot is too difficult to see, then saturate the cloth slightly more. If the spot appears heavy or runny, then the cloth is oversaturated. 2. ... continues for two pages .... " The REASON one has to look at the material on the specimen slide by reflected light is BECAUSE the stuff migrates and forms a MONO-molecular layer that you will NOT see by direct observation. The cautions regarding too little and too MUCH depend on human discretion and "experience." These instructions for Cramolin are exactly the same as the scenario for the application of lubricant on the HD platters as related to me by all three of the local HD repair companies. I respectfully suggest to our "anonymous" poster and to "Dr. Ken" that they get their facts straight. If you want the name of the chemical used as the HD platter lubricant, call the companies I cited in a prior posting. Thad Floryan [ thad@cup.portal.com (OR) ..!sun!portal!cup.portal.com!thad ]
thad@cup.portal.com (Thad P Floryan) (07/17/89)
More from our "anonymous" poster forwarding other people's responses (indented):
Let me jump in here: I worked at a plant where we plated magnetic
coatings onto platters and drums for computer drives. The company I
worked for also built the heads that were used. I cannot believe
Seagate would have people manually applying a "lubricant" onto the
disks with "rags".
^^^^
How about "linen cloth"? THAT's what they use; my term "rags" was not meant to
conjure up visions of a back room full of grease-monkeys in dirty overalls! :-)
We used to plated coatings as thin as .000005" (that's 5 millionths of
an inch!), this was less than the surface finish RMS (roughness
measurements) and ANY other substance visable on the surface was
grounds for rejection (the disk). Most of the plated media didn't
require "lubrication" (one exception was the drums used in the
Minuteman Missle system....it had a Rhodium top plate) but when they
do it's generally hard Chrome plated about 25 microinches...anyways,
what I have to say is just a tiny bit of dust in ANY type of wiping
material will scratch a platter something fierce...I know, I've
scraped a few in my time.....
I doubt the "plated media" in MODERN drives possessing Whitney-arm, thin-film
heads is Chrome; the magnetic properties are inadequate. "CrO2" media on audio
tapes is not "Chrome", it's chromium dioxide and colored black; "normal" audio
media is ferric oxide and "rust-colored"; the Seagate drive I opened (see below)
has a bronze-colored media with a chemical coating (lubrication).
Whatever the disk drive "plated media" material IS, it's unbelievably hard. I
opened one of my defective ("stiction") Seagate ST251 drives and performed some
experiments on it:
1) lightly touching the platter surface with a screwdriver blade while the disk
was spinning left NO evidence of the contact.
2) blowing cigarette smoke onto the platters while running DiskPerf caused no
noticeable effect.
3) spitting onto the rotating platter during DiskPerf (yeah, I'm really getting
mean here! :-) brought up a R/W error requestor; manually spinning the shaft
and moving the head assembly while wiping the platter with a Kleenex (tm)
soaked with Ronsonol (tm) lighter fuel cleared up the R/W error as verified
by another DiskPerf run.
4) depositing a fingerprint on the platter, manually spinning the main spindle
shaft, and positioning the heads so they'd ride over the fingerprint, a VERY
noticeable drag was encountered at the point of contact with the fingerprint.
Continuing to spin the main shaft, the heads eventually erased all evidence
of the fingerprint; the drive didn't pass a DiskPerf until I again cleaned
the platter (and, by implication, the head) with Ronsonol.
5) my home microscope only goes to 100x, so I couldn't see the "white worms"
as I did at the HD repair place. But careful examination of the drive
clearly shows the "heads" ARE in contact (buffered by the lubrication) with
the platter surface during normal operation (determined by sighting across
the disk surface looking into a high-intensity lamp). The head sled is a
rectangular block about 1/8"x1/4" and about .050" thick, whose R/W surface
is as super-polished as the surface of the platters.
6) Final experiment: moved the heads to PARK position and waited awhile; there
was VERY DEFINITE RESISTANCE ("stiction") when attempting to move them later.
Moved the heads to the middle of the platter and waited awhile; there was NO
noticeable resistance when attempting to move them later.
The anecdotes posted by our "anonymous" poster tend to suggest "old" disk
technology, pre-Whitney and possibly pre-Winchester; not relevant TODAY.
The "stiction" problem with the drives is one characterized by physics and NOT
by chemistry; more specifically: fluidics. If you haven't done so already, do
the simple experiment I described in the previous posting on this subject (with
the two glass plates (or microscope specimen slides) and a drop of water).
And, for everyone's entertainment, amusement and enjoyment, I'll bring the drive
to this week's BADGE meeting where we'll attempt to induce a head crash after
everyone's had a chance to SEE the insides of the drive for themselves. Try to
dream of a way to make it fail; I've already dropped it and wacked it on the
side with a wooden mallet while it was operating ... it continues to function
after clearing the momentary R/W error. As I've said before, the basic design
of the drive IS good, it's only the manufacturing flaw regarding lubrication
that is causing all the problems.
Thad Floryan [ thad@cup.portal.com (OR) ..!sun!portal!cup.portal.com!thad ]dougp@voodoo.ucsb.edu (07/18/89)
-Message-Text-Follows- In article <20538@cup.portal.com>, thad@cup.portal.com (Thad P Floryan) writes... > as I did at the HD repair place. But careful examination of the drive > clearly shows the "heads" ARE in contact (buffered by the lubrication) with > the platter surface during normal operation (determined by sighting across > the disk surface looking into a high-intensity lamp). The head sled is a >Thad Floryan [ thad@cup.portal.com (OR) ..!sun!portal!cup.portal.com!thad ] Unfortunatly, "sighting the disk surface looking into a high-intensity lamp" is not a good enough test in this case to tell if the heads are in contact with the disk. Heads fly at an extreemly low altitude (on the order of the wave length of light), in fact the way the flying hight of a head is measured is to fly the head on a glass disk, shine white light through the disk and onto the head, and measure the wavelength of light which is reflected. (looks like a rainbow since the front of the head flies higher than the back) This uses the same effect which gives bubbles their color. Plated media holds up much better than oxide, where I work, we make hard disk head testors. We fly heads in a very dusty room to test and calibrate our testors (we use reject heads and disks). Plated media seems to last forever, we occaisionaly have to clean the heads, but the media does not scratch easily. oxide media (especialy 14" disks) is likely to selfdistruct if it is left flying for several hours. The purpose of the lubrication is to avoid stiction. dry disks will stick to the heads and prevent spinning. Too much lubrication will cause the same problem, depending on the lubricant. Disk manufacturers like to keep the lubricant they use a secret so I doubt Segate will tell anyone what they use. Douglas Peale