thad@cup.portal.com (Thad P Floryan) (10/21/89)
Amiga Survives 7.0 Earthquake
Makes a nice headline, eh? :-)
Well, mine did (as did other computers in my home office). By the time I
could get home from San Jose after Tuesday's ``Big One'' (normally a 9 minute
drive, this time taking 90 minutes), even the UPS had run down and I could
just peer over a pile of books and other stuff blocking a hallway to see that
the computers had not toppled or fallen over.
Without wishing to bore with earthquake details, I'll simply make the
observation that everything appeared to move in unison and thus there were
no (apparent) high-G shocks to operating equipment.
Today (Friday) was the first day I could even get to the computers (after
clearing all the blockage) and try them out. Everything came up just fine,
even a 5-high stack of Maxtor HDs.
I was even more (pleasantly) shocked when the RP06s, RP07s and RA81s on the
office computers came up fine at 9:30 am Wednesday; I had surely expected at
least the RP06 drives to suffer head crashes.
This bring up an interesting technical question: what is the equivalent ``G''
force experienced by equipment during an earthquake? Is this question even
relevant, or should the horizontal- and vertical-axis oscillations be taken
into consideration? I ask because (typical) specs for disk drives state:
Shock (inputs to frame of drive):
Operating shock (all axes): 11 mS pulsewidth (1/2 sine) .......... 2G
Vibration (inputs to frame of drive):
Operating vibration (all axes):
5-25 Hz, 0.006 inches P-P
25-500 Hz, 0.2G peak acceleration
How do those shock and vibration specs relate to the "real world"?
The stands upon which all my systems are operated are highly modified
"Tiffany" stands (Tiffany in this sense is NOT the jewelry company but,
instead, a mfr of extremely heavy-duty typewriter stands) whose bases are
loaded (my mods) with heavy wood platforms each supporting a UPS and other
peripherals. I think it unlikely ANYTHING could tip these over. Not one
moved more than 2 inches, yet a 2000+ lb. bookcase moved 4 inches from one
wall, and all my (full) filing cabinets danced-out 6 inches from another
wall. I don't even want to discuss the other bookcases that collaped
and/or fell, and the other messes.
Sheesh, my office building (2 stories, with 2 levels of underground
parking) is now 1-1/2" higher in front, and 3" higher at the rear ... the
entire building moved as a unit, so "earthquake construction" IS valid.
The biggest cause of personal injury were the g*d-d*mned collars which
surround ceiling fire sprinkers ... the (decorative-only) collars popped
out and hit people on their heads.
As a bit of weird coincidence, I was away from my desk at the time talking
to the office manager describing how we layed out the office floorplan and
explaining to her how the walls were moveable ... 1 second later they MOVED.
She screamed, I grabbed her and leaned at 45 degrees facing a load-bearing
wall supporting us up with my other hand (my back is still aching); everyone
else in the building was knocked over. One thing that was VERY OBVIOUS TO
ME: do not EVER, under ANY circumstances, stand in a doorway during an
earthquake. As I was holding the office manager I was looking at our front
doors and how they were swinging back and forth like scythes ... jeez, those
damned doors couldv'e sliced a body in half (like a paper cutter).
Someone calculated that Tuesday's earthquake had the effective power of a
2 to 3 megaton H-bomb. That was a 7.0 earthquake, 25 miles from my office,
32 miles from my home, and 70+ miles from the disaster in San Francisco and
Oakland. Kinda gives one a new appreciation for the forces of nature.
Which leaves me, in conclusion, asking how other people's systems fared, and
what, if anything, can be done to prevent system damage with forces of this,
or greater, magnitude.
Thad Floryan [ thad@cup.portal.com (OR) ..!sun!portal!cup.portal.com!thad ]portuesi@tweezers.esd.sgi.com (Michael Portuesi) (10/23/89)
>>>>> On 21 Oct 89 10:35:43 GMT, thad@cup.portal.com (Thad P Floryan) said:
thad> Which leaves me, in conclusion, asking how other people's systems fared, and
thad> what, if anything, can be done to prevent system damage with forces of this,
thad> or greater, magnitude.
thad> Thad Floryan [ thad@cup.portal.com (OR) ..!sun!portal!cup.portal.com!thad ]
Well, my Amiga survived, even though it was at home running when the
quake hit. Fortunately the hard disk drive suffered no damage, and I
was very lucky the monitor didn't fall off the milkcrate it was
perched upon.
My workstation here crashed when the quake hit, and I was unable to
determine if the very important work I saved seconds before the quake
hit had survived, until I returned to work Thursday.
As far as preventing system damage, is there some way that hard disks
can be designed to autopark during periods of non-use, and to withdraw
the heads if the mechanism is jolted? In most cases, the data is much
more costly than the systems storing and manipulating it.
--M
--
__
\/ Michael Portuesi Silicon Graphics Computer Systems, Inc.
portuesi@SGI.COMesker@abaa.uucp (Lawrence Esker) (10/23/89)
In article <23238@cup.portal.com> thad@cup.portal.com (Thad P Floryan) writes: > > Amiga Survives 7.0 Earthquake > >Makes a nice headline, eh? :-) Yes it does. Where's C='s ad company? >This bring up an interesting technical question: what is the equivalent ``G'' >force experienced by equipment during an earthquake? Is this question even >relevant, or should the horizontal- and vertical-axis oscillations be taken >into consideration? I ask because (typical) specs for disk drives state: > >How do those shock and vibration specs relate to the "real world"? I have always wondered myself. I work for a company that does vibration and shock testing of all products before they are released. I've always wondered if the minimum levels we test to is resonable or overkill for the real world. >The stands upon which all my systems are operated are highly modified >"Tiffany" stands (Tiffany in this sense is NOT the jewelry company but, >instead, a mfr of extremely heavy-duty typewriter stands) whose bases are >loaded (my mods) with heavy wood platforms each supporting a UPS and other >peripherals. I think it unlikely ANYTHING could tip these over. Not one >moved more than 2 inches, yet a 2000+ lb. bookcase moved 4 inches from one >wall, and all my (full) filing cabinets danced-out 6 inches from another >wall. I don't even want to discuss the other bookcases that collaped >and/or fell, and the other messes. The shape of the object has more to do with it than the weight: +------+ Falls over | | | | | | +--------+ Wobbles | | | | | | | | +--------------+ Doesn't move | | | | | | +------+ +--------+ +--------------+ A force vector forms at the point of the object's center of gravity. The weight force pointing down combines with the earthquake force moving sideways. If the combined vector points from the center of gravity to a place outside of the base of the box, the box will move. +---> Earthquake |\ | \ | \ Weight v x Combined Of coarse, this was the simplistic laymens description. Didn't feel like writing a book. >Which leaves me, in conclusion, asking how other people's systems fared, and >what, if anything, can be done to prevent system damage with forces of this, >or greater, magnitude. Several colleages were in the area at the time for a seminar. I should have been there but got sent to Ft. Lauderdale, FL to fix a customer fire. They had lots to talk about when we all got back. >Thad Floryan [ thad@cup.portal.com (OR) ..!sun!portal!cup.portal.com!thad ] -- ---------- Lawrence W. Esker ---------- Modern Amish: Thou shalt not need any computer that is not IBM compatible. UseNet Path: __!mailrus!sharkey!itivax!abaa!esker == esker@abaa.UUCP
theobaby@well.UUCP (Paul Theodoropoulos) (10/27/89)
I was at Candlestick when it hit - upper deck. 62,000 people took Candlestick
Park for a test drive. When I got home (Bernal Heights in S.F., sort of way
outer Mission district), found my disk drive hanging in mid-air by it's power
and scsi cords. The tall upper portion of my desk had tipped forward, but
came to rest against my monitor, thus saving it from toppling. Amazingly, NO
damage. It really helps if your house has a good wood frame, and is on solid,
Serpentine rock. It seems the house just swayed, rather than jolted. Hell of a[`Ol
sway, though...
>>>>>No bandwidth wasting signature for me! The K.I.S.S. principle.<<<<<<