Discussion:
mysterious hard hangs, two different sun4m's
(too old to reply)
Skeezics Boondoggle
2002-09-02 09:56:27 UTC
Permalink
the problem:

i have both an ss4 and an ss20 that are locking up tight, sporadically,
for no apparent reason. when they go they're completely frozen up; won't
respond to L1-A, pointer freezes, keyboard won't respond, network dead.

the hardware:

ss4, 128mb, solaris 2.6, one internal disk, cdrom+floppy, onboard tcx
video. only locks up during interactive use, but often runs fine for
weeks or months with daily usage with no problems - other times it hangs
two or three times a day.

ss20, 128mb, solaris 7, one internal disk, cdrom+floppy, 4mb vsimm. was
running headless with zero problems. now it locks up too!

both machines are in my basement cave, which is comfortably cool all year
'round.

the background:

the ss4 has been my primary machine at home for many years. i was too
lazy to do a proper reinstall from scratch, so it is a bit of a mongrel -
running solaris 2.6 (upgraded from 2.5 or 2.5.1), and it's been through a
whole series of configuration changes and tinkering. :-) for some time it
had a fore atm card in it, because i was feeling masochistic and wanted to
fling some bits over the fiber at my old asx-100... i soon got over that,
then installed an fsbe (later a sunswift) and ipfilter, and was my dsl nat
gateway and firewall, with a three-slot and-a-taco disk enclosure hanging
off it. then i found a different ss20 to be the firewall machine and run
some services and stuff, and got those off the ss4.

later i found another ss20 and intended to make it my new desktop and put
nextstep/openstep on the ss4 instead, because building three-architecture
(m68k/sparc/hppa) fat binaries is cool. (quad fat is cooler, except that
would mean having to own an x86 box...)

the symptoms and diagnosis:

at first i thought the hangs were hardware related; the 110mhz ss4 clocks
its sbus at 22.5mhz and that seems to make some sbus cards unhappy. in
all the hangs, though, i never found ANYTHING in any of the system logs,
on the console, or during any of the post runs or self tests. even after
i'd stripped out all the extra hardware, pulled off the serial splitter
cable, removed the external disks and uninstalled disksuite, and fscked
the internal drive twice, pkgchk'ed and rpm -vV'ed all my installed
software, and found absolutely NOTHING to indicate a hardware problem, i
finally just got fed up - and a couple of power outages last week were the
last straw.

so i decided to move the ss4 off my desk and get off my lazy butt and
update the internal network. :-) the headless 4-way ss20 firewall machine
is now on ups power with the F330. the dual-75 ss20 now has the ss4's 20"
monitor, type5 and mouse. and the ss4 was finally going to get a fresh
nextstep 3.3 or openstep 4.2 install...


then after a day of getting my recently jumpstarted and patched solaris 7
machine updated with all my latest rpm builds (get paid to build and
deploy 'em at work, saves a TON of time just downloading 'em and
installing 'em at home :-) i was quite pleased with how zippy it was with
the sx video enabled... for giggles, before i nuked and repaved the ss4, i
stuck another monitor on it and a spare type6 keyboard, and decided to run
a few tests. (for posterity, an informal benchmark shows that the
dual-75mhz supersparc-ii can render 98 jolene blalock .jpgs with 'xv' 2:10
faster than the 110mhz ss4, while the 110mhz sparcbook 3gx, sadly, takes a
full 5:13 longer, largely because it had to scale down most of the images,
so it wasn't a fair test. :-)

another test was running a two player computer vs. computer game on the
latest 'xconq' cvs snapshot, which i'd just rebuilt today... imagine my
chagrine when the ss20 locked up tight, while the ss4 sat there patiently,
wondering why the zimbabwean mplayer had suddenly stopped talking to it...

okay, i thought, these are *totally* separate machines, but now the ss4 is
*fine* and the ss20 is hanging. i'm using my old type5 and my old mouse
on the new machine... could THAT be the problem? dug up a spare type5,
still in bubble wrap, which turned out to have that godawful "pc layout"
(anyone actually LIKE those? i'll gladly trade for a unix layout type5,
with the control key in the right place, and NO, thank you, screwing with
xmodmap is annoying and i refuse to do that on principle) and swapped out
the keyboard. still froze. swapped out the mouse. still froze.
checked the power cord with a meter: 120V. opened the case and blew out
a tiny bit of dust, but this was a fairly new machine and had been running
just fine, headless, for a couple of months. checked that everything was
seated, all cables fine, etc.

at least i can now reproduce the problem with some sort of regularity:
power cycle and boot up, log back in, start up a two-player xconq game and
about 12-18 turns in, bingo, the 20 locks up and the 4 is fine... (i'm
composing this on the 4 right now.)

okay, so the only other thing in common across the two machines is that
i'm running olvwm on top of openwin - yeah, i know, but i think the folks
here can appreciate how convenient it is to have the same login name and
uid and windowing environment over six jobs in the last 11 years... :-)
with all the gyrations sun has done with their X environment, it's nice to
just set up a new home directory by unpacking a small tarball and getting
to work. :-) cde? please. gnome? yet another conspiracy to sell ram
upgrades...

but having checked or swapped out the only hardware components that were
common between the two machines, the only thing i can think of now is that
either my window manager or something in my login environment or some bit
of opensource software that i've built is causing it. or, perhaps this
particular spot on my desk is the sun4m VORTEX OF DOOM, and any
unfortunate sparc v8 pizzabox i put there is bombarded with wierd cosmic
rays or something...

anyway, i'm at a loss. i suppose i should try enabling the deadman code
in the kernel, see if i can get ANY kind of debugging info out of it...
i'm not sure what advice y'all might have that i haven't already thought
of or tried; in 12 years banging on sun hardware these kinds of hard hangs
are so rare that i'm just *mystified* that i've now moved the problem from
one machine to another by just swapping their places on the desk. i think
it's gremlins. a cia plot. sunspots. or i'm just going mad.

"maybe it's time to move..." :-)

ah, well. graphics are overrated anyway. i'll just put them back in a
stack (oooh, it's a 'tower of power' :-) and run them all headless, pull
the vt320 off the netapp and get a serial port switch. 80x24 is fine for
'pine' and 'lynx'. hell, Real Men read their mail with 'cat' and flow
control...

sigh.

thanks for letting me rant. if anyone is running olvwm on a sun4m and
suffering sporadic hangs, maybe we have a culprit... any other advice or
suggestions from the peanut gallery gladly accepted.

-- skeez
"Loomis, Rip"
2002-09-03 01:33:32 UTC
Permalink
if anyone is running olvwm on a sun4m and suffering sporadic hangs,
maybe we have a culprit...
Not exactly the same symptoms, but I had sporadic issues with
ctwm under Solaris 2.5/2.5.1 which turned out to be Solaris-side
bugs. Like you, I was running it at the time because it was nice to
be able to take an entire home directory with dot files around and
have it Just Work. (I don't remember all the issues/symptoms...one was
a window titles getting b0rked, and another was system hangs IIRC.)

The place at which I worked at the time had on-site Sun support
folks, so I called them, traded core dumps, binaries, and info with
them, and after about 3 weeks was told essentially, "It's apparently a
bug in Solaris, but you're the only one reporting it so we'll add to
the 'fix when everyone runs out of other things to do' list". Not
one of the best experiences I ever had with Sun support, but those
folks were amazingly helpful on all the other issues I ran into during
that period.

In the end, I went over to the darkside and started using CDE--other
folks had decided to standardize on it, and it allowed me to get the
virtual workspaces I wanted *and* full support for bug fixes. (About
the same time I finally learned enough vi to get around and stopped
using emacs*.) And yes, this was CDE on a SPARC 10 with a single SM40--
not blazingly fast, but usable.

Not sure that this helps, but it at least tends to confirm that the
problems you're seeing might actually be bugs in Solaris...and that
those bugs might not get fixed any time soon.

--Rip

* I will let those who care enough, debate the question of vi -vs- emacs
being the dark side...
James Lockwood
2002-09-03 07:06:43 UTC
Permalink
Post by Skeezics Boondoggle
anyway, i'm at a loss. i suppose i should try enabling the deadman code
in the kernel, see if i can get ANY kind of debugging info out of it...
i'm not sure what advice y'all might have that i haven't already thought
of or tried; in 12 years banging on sun hardware these kinds of hard hangs
are so rare that i'm just *mystified* that i've now moved the problem from
one machine to another by just swapping their places on the desk. i think
it's gremlins. a cia plot. sunspots. or i'm just going mad.
How hard of a lock is it? Does the system still respond to L1-A?

If so, boot with kadb and try to reproduce it. Once it hangs, break into
the debugger and get a backtrace. First order analysis: suspect hardware
if the hang point wanders dramatically, suspect software if it stays in a
relatively small number of places. Using the SX stresses some weird parts
of the memory controller.

Is the watchdog reset enabled? If it is a "hard" hang, does it respond to
a keyboard replug event (which enters the kernel at a higher interrupt
priority than L1-A)?

Try pulling one CPU and see what happens. If you still get the hangs,
swap it for the other. Drop down to a single DIMM. You know, standard
problem isolation techniques.

Unless your desk has a Tesla coil directly underneath it I wouldn't worry
about the problem migrating with position. :)

-James
Skeezics Boondoggle
2002-09-03 18:14:36 UTC
Permalink
On Tue, 3 Sep 2002, James Lockwood wrote:

[snip]
Post by James Lockwood
Unless your desk has a Tesla coil directly underneath it I wouldn't
worry about the problem migrating with position. :)
damn! i completely forgot about that pesky Tesla coil. :-)

reminds me of the story about the utterly exasperated tech support person
who could not diagnose the trouble, and finally asked the caller, "has
ANYTHING changed in the last few days that might explain what's gone
wrong?" to which she replied, "well, it did catch fire yesterday..."

no, my machines haven't caught fire. i checked that. :-)

thanks to all for the suggestions; i'll have to try a combination of
things, obviously - latest patches, more methodical approach to debugging
the hardware end of things...

but i realized that the other common feature is that i've been building
all my solaris code (as much as possible, anyway) under the sparcworks 5.0
compilers, not gcc, for both the 2.6 and 7 environments. since these hard
hangs have happened on both the ss4/tcx and the ss20/sx i'm suspecting
that it's something i've built - or maybe a compiler bug, or a solaris bug
that's being tickled by olvwm or openssl/openssh or xconq/tcl/tk or who
knows what..."doctor, it hurts when i run xconq!" "so don't do that..."

it used to be easy: blame netscape. netscape has crashed every X server
i've ever used on every platform at one time or another, so that was an
obvious suspect. when starting up java under netscape used to cause
freezes, patches alleviated that somewhat - now i get core dumps, or the X
server crashes instead... at least i avoid having to power cycle the
machine. :-) but netscape hasn't been giving me grief, lately.

thanks for the tips. i'd like to solve this mystery. i mean, if i wanted
to have to reboot my machine every day, i'd run w... ew, i can't even say
it. :-)

cheers,

-- skeez
Dan Sikorski
2002-09-04 02:40:33 UTC
Permalink
Post by Skeezics Boondoggle
Post by James Lockwood
Unless your desk has a Tesla coil directly underneath it I wouldn't
worry about the problem migrating with position. :)
damn! i completely forgot about that pesky Tesla coil. :-)
Ya know, sometimes it's not that dramatic. In an office of a client of
mine, a girl used to have a PC (yeah, that was her first problem0) that
crashed constantly, at least once a day. She was basically told to live
with it, so she did. Then she moved her office around, and put the PC
on her desk, and it didn't crash on her for months. Then when she got a
new PC, it was put on the floor, and had stability problems. After it
was moved to on the desk, all was fine again. Two machines that had
problems on the floor, and were fine on the desk. There's nothing near
there that i know of that would cause such problems (they're a RV
manufacturer). And that's not the only room in that building that has
strange problems like that.

-Dan Sikorski
Kurt Huhn
2002-09-04 02:41:29 UTC
Permalink
Post by Dan Sikorski
problems on the floor, and were fine on the desk. There's nothing
near there that i know of that would cause such problems (they're a RV
manufacturer). And that's not the only room in that building that has
strange problems like that.
Friday last week we had a machine that performed differently in three
locations of the office (big loft area). In one area it failed to boot
entirely, one area it booted but X was all fouled up, and another area
it booted and everything was fine. The same behavior was reproducable
several times, and the behavior did not migrate from one physical
location to another. The user was instructed to move thier desk...
--
Kurt "What me look like, ricecake monster?
***@k-huhn.com Me Cookie Monster! Me need COOKIE!" --Cookie
Monster
Eric Dittman
2002-09-04 02:41:40 UTC
Permalink
Post by Dan Sikorski
Ya know, sometimes it's not that dramatic. In an office of a client of
mine, a girl used to have a PC (yeah, that was her first problem0) that
crashed constantly, at least once a day. She was basically told to live
with it, so she did. Then she moved her office around, and put the PC
on her desk, and it didn't crash on her for months. Then when she got a
new PC, it was put on the floor, and had stability problems. After it
was moved to on the desk, all was fine again. Two machines that had
problems on the floor, and were fine on the desk. There's nothing near
there that i know of that would cause such problems (they're a RV
manufacturer). And that's not the only room in that building that has
strange problems like that.
HV lines under the floor?
--
Eric Dittman
***@dittman.net
Check out the DEC Enthusiasts Club at http://www.dittman.net/
Dan Sikorski
2002-09-04 03:05:49 UTC
Permalink
Post by Eric Dittman
HV lines under the floor?
What frequency do HV lines typically run at? 60hz would cause noticible
interference in monitors, from my experence. (previous employer had an
office out in the plant with some sort of transformers on top of it.
Monitors would have horrible interference unless they were running at 60
or 120hz refresh rates.)

-Dan Sikorski
Scott Newell
2002-09-04 03:05:30 UTC
Permalink
Post by Dan Sikorski
What frequency do HV lines typically run at? 60hz would cause noticible
The same frequency as your power distribution grid.


newell
Greg A. Woods
2002-09-04 05:41:59 UTC
Permalink
[ On Tuesday, September 3, 2002 at 21:41:40 (-0500), Eric Dittman wrote: ]
Subject: Re: [rescue] mysterious hard hangs, two different sun4m's
HV lines under the floor?
Once upon a time I did some brief computer consulting work at the
Ontario Hyrdo high voltage lab out in the west end of Toronto, or rather
in one of the offices next door to that lab. They had some interesting
problems keeping some of their computers running in some locations in
the building -- and lots of strange and wonderful tales to tell! :-)
--
Greg A. Woods

+1 416 218-0098; <***@ieee.org>; <***@robohack.ca>
Planix, Inc. <***@planix.com>; VE3TCP; Secrets of the Weird <***@weird.com>
Eric Dittman
2002-09-04 03:17:01 UTC
Permalink
Post by Dan Sikorski
Post by Eric Dittman
HV lines under the floor?
What frequency do HV lines typically run at? 60hz would cause noticible
interference in monitors, from my experence. (previous employer had an
office out in the plant with some sort of transformers on top of it.
Monitors would have horrible interference unless they were running at 60
or 120hz refresh rates.)
Most are at 60Hz. The magnetic field induced by the HV lines
can cause different types of problems.

My brother called me about a problem with a PC at a concrete
plant that was having problems only in the field. The PC
controlled the truck scales. The PC was supplied by the
company as part of the truck scales, so the PC was sealed
against dust. The PC was located inside the scale house
which was air conditioned.

I first had them have the scale company put in a power
monitor. Over a period of two weeks there were no power
fluctuations monitored at the PC (a power conditioner was
standard equipment). The next step was an environmental
monitor. The temperature and humidity were well within
the accepted ranges. Monitoring the inputs from the scale
was the next step. These lines were filtered and used
optoisolation and were clean.

As the final step I had him build a crude Faraday cage to
house the PC, keyboard, mouse, and monitor. That worked
pretty well, so they had a company come in and build a
better permanent Faraday cage. All is well now.
--
Eric Dittman
***@dittman.net
Check out the DEC Enthusiasts Club at http://www.dittman.net/
Al Potter
2002-09-04 03:14:24 UTC
Permalink
Think: Janitorial Staff

Floor Sweepers don't typically reach up on the desk. It could be physical
trauma (bump, Bump, BUMP), or EM noise from the relatively high amp and
probably poorly shielded motors in the sweepers.

Then again, it could be $BOFH_Excuse.


When alse fails, refer to RFC 2321 <http://zvon.org/tmRFC/RFC2321/Output/inde
x.html>



AL
Post by Dan Sikorski
Ya know, sometimes it's not that dramatic. In an office of a client of
mine, a girl used to have a PC (yeah, that was her first problem0) that
crashed constantly, at least once a day. She was basically told to live
with it, so she did. Then she moved her office around, and put the PC
on her desk, and it didn't crash on her for months. Then when she got a
new PC, it was put on the floor, and had stability problems. After it
was moved to on the desk, all was fine again. Two machines that had
problems on the floor, and were fine on the desk. There's nothing near
there that i know of that would cause such problems (they're a RV
manufacturer). And that's not the only room in that building that has
strange problems like that.
-Dan Sikorski
_______________________________________________
rescue list - http://www.sunhelp.org/mailman/listinfo/rescue
Francisco Javier Mesa-Martinez
2002-09-04 05:02:09 UTC
Permalink
Post by Eric Dittman
As the final step I had him build a crude Faraday cage to
house the PC, keyboard, mouse, and monitor. That worked
pretty well, so they had a company come in and build a
better permanent Faraday cage. All is well now.
Theoretically the PC case is supposed to be a Faraday box, the fact that
it picked up the E field from a nearby powergrid would be enough to allow
you to report the manufacturer to the FCC. This is why I am always tempted
to report Fry's whenever I see one of those transparet FeeCee cases on
display....
Bill Bradford
2002-09-04 05:06:47 UTC
Permalink
Post by Francisco Javier Mesa-Martinez
Theoretically the PC case is supposed to be a Faraday box, the fact that
it picked up the E field from a nearby powergrid would be enough to allow
you to report the manufacturer to the FCC. This is why I am always tempted
to report Fry's whenever I see one of those transparet FeeCee cases on
display....
They cant get in trouble for selling a *case*. If the USER buys a motherboard
and puts it in... its not Frys' problem.

Kinda like how Apple used to *not* sell the RF modulator for the Apple II -
but hey, the *DEALER* will sell you one! If the user causes the RF problems,
its not the manufacturer's fault... *grin*

Bill
--
bill bradford
***@mrbill.net
austin, texas
Tim H.
2002-09-05 01:14:26 UTC
Permalink
On Tue, 3 Sep 2002 22:02:09 -0700 (PDT)
Post by Francisco Javier Mesa-Martinez
Theoretically the PC case is supposed to be a Faraday box, the fact
that it picked up the E field from a nearby powergrid would be enough
to allow you to report the manufacturer to the FCC. This is why I am
always tempted to report Fry's whenever I see one of those transparet
FeeCee cases on display....
Actually, the FCC doesn't care if your PC picks up noise, it only cares
if it broadcasts noise. THe official language is something to the
effect "(1)this device may not cause harmful interference (2) this
device must accept any interference received including interference that
may cause undesired operation. FCC doesn't regulate receivers, other
than who may listen in on what frequencies, they regulate transmitters.

Tim
Eric Dittman
2002-09-04 05:09:32 UTC
Permalink
Post by Francisco Javier Mesa-Martinez
Post by Eric Dittman
As the final step I had him build a crude Faraday cage to
house the PC, keyboard, mouse, and monitor. That worked
pretty well, so they had a company come in and build a
better permanent Faraday cage. All is well now.
Theoretically the PC case is supposed to be a Faraday box, the fact that
it picked up the E field from a nearby powergrid would be enough to allow
you to report the manufacturer to the FCC. This is why I am always tempted
to report Fry's whenever I see one of those transparet FeeCee cases on
display....
Don't forget about the mouse, keyboard, video, etc. cables.
Those are rarely properly shielded.
--
Eric Dittman
***@dittman.net
Check out the DEC Enthusiasts Club at http://www.dittman.net/
Patrick Giagnocavo +1.717.201.3366
2002-09-04 05:24:32 UTC
Permalink
A long time ago I worked with someone who headed up the Dell SVR4 Unix
unit.

How many of you know that Dell even *had* a version of SVR4 :-)

Anyways, he said that whenever they had weird crashes and hangs, the
first response was to insist the customer put the system on a UPS.

This usually solved the problem.

Don't know if this has already been suggested on the thread or not.

./patrick
d***@cca.org
2002-09-04 07:00:30 UTC
Permalink
Post by Patrick Giagnocavo +1.717.201.3366
A long time ago I worked with someone who headed up the Dell SVR4 Unix
unit.
How many of you know that Dell even *had* a version of SVR4 :-)
I think I have it on DAT somewhere... :-)

------ David Fischer ------- ***@cca.org ------- http://www.cca.org -------
---------- "Anything Jesus can do, I can do better." - The Locust ----------
Bill Bradford
2002-09-04 09:20:23 UTC
Permalink
Post by Patrick Giagnocavo +1.717.201.3366
A long time ago I worked with someone who headed up the Dell SVR4 Unix
unit.
How many of you know that Dell even *had* a version of SVR4 :-)
Which PC maker was it that had a SPARC clone in the early 90s? I had the
SunOS distribution for it on tape somewhere.. I forget who it was, but it
was one of the Austin-based companies, and was *not* Dell..

(dammit, the name is on the tip of my tongue...)

Bill
--
bill bradford
***@mrbill.net
austin, texas
Patrick Giagnocavo +1.717.201.3366
2002-09-04 12:18:26 UTC
Permalink
Post by Bill Bradford
Post by Patrick Giagnocavo +1.717.201.3366
A long time ago I worked with someone who headed up the Dell SVR4 Unix
unit.
How many of you know that Dell even *had* a version of SVR4 :-)
Which PC maker was it that had a SPARC clone in the early 90s? I had the
Was that CompuAdd? They went under about 1994 or 1995 I think.

I could never understand the reasoning that since it was just as good
as a Sun, it should cost the same amount. Every clone vendor whose
pricing I checked out at that time wanted about ( <Sun list> * 0.95)
for their hardware.

Of course at that time I was a little clueless about how the Unix
market worked - I couldn't understand why the guys at Unix Expo didn't
really want to talk to me when I mentioned I would be buying one
system.

./patrick
Bill Bradford
2002-09-04 14:22:07 UTC
Permalink
Post by Patrick Giagnocavo +1.717.201.3366
Was that CompuAdd? They went under about 1994 or 1995 I think.
Yeah, that was it.

Bill
--
bill bradford
***@mrbill.net
austin, texas
Kurt Mosiejczuk
2002-09-04 07:32:03 UTC
Permalink
Post by Francisco Javier Mesa-Martinez
Theoretically the PC case is supposed to be a Faraday box, the fact that
it picked up the E field from a nearby powergrid would be enough to allow
you to report the manufacturer to the FCC. This is why I am always tempted
to report Fry's whenever I see one of those transparet FeeCee cases on
display....
Maybe I'm wrong, but isn't a device to accept any interference, but
generate none of its own?

--Kurt
Francisco Javier Mesa-Martinez
2002-09-04 08:24:51 UTC
Permalink
Post by Kurt Mosiejczuk
Post by Francisco Javier Mesa-Martinez
Theoretically the PC case is supposed to be a Faraday box, the fact that
it picked up the E field from a nearby powergrid would be enough to allow
you to report the manufacturer to the FCC. This is why I am always tempted
to report Fry's whenever I see one of those transparet FeeCee cases on
display....
Maybe I'm wrong, but isn't a device to accept any interference, but
generate none of its own?
A simple conducting cage can be used to shield electronic equipment.
Basically this allows to cancel all electric fields outside the box, the
side effect is that it also cancels internal electric fields to the
outside world.

Faraday cages were the thought experiment for modern electric isulation.

The problem is that most devices in the super-KHz ranges do generate a
hefty amount or radio activity. Thus shielding is quite mandatory, however
American engineering regulations are usually very lax, thus the fact that
you can actually market cheap plastic computer cases, that will most
likely hold 1/2GHz processors. Modern computer systems due to the
extremely large number of traces in their boards (as well as large
switching components like the processor) are incredible radio noise
generators. They are also more sensitive to noise interferece... and now
that we have 2.4GHz processors, in a wireless world that runs mostly in
the 2.4GHz spectrum....

Then we have the poor heat conductivity that those transparent cases do
have. Thus putting a thermally sensitive device, which generates a LOT of
heat, inside a nice insulator is not a good idea IMHO. Why am I amazed by
all this? Well when I went to Fry's I saw these things for the first time,
in the price tag they had written "Great for Overcloking!". So the people
who buy these transparent cases, are not only laughing at most laws of
Electrodinamics, but they are also pissing on the laws of Thermodynamics.
That is why they deserve the boot in the head! And Fry's too, not only for
that but for many other reasons. :-)
Tim H.
2002-09-05 01:21:26 UTC
Permalink
On Wed, 4 Sep 2002 01:24:51 -0700 (PDT)
Post by Francisco Javier Mesa-Martinez
Thus putting a thermally sensitive device, which generates a LOT of
heat, inside a nice insulator is not a good idea IMHO. Why am I amazed
by all this? Well when I went to Fry's I saw these things for the
first time, in the price tag they had written "Great for
Overcloking!".
Actually, the heat transfer from hot air in the box, to the box, to the
air outside the box isn't very good, and if they put in a glass window
it would probably dissapate heat as well as painted metal. The
overclockers that buy that stuff have all gone to watercooling anyway, I
know of some running waterblocks on processor and on hard disks.
Besides, what Fry's meant was "great for overclocking, like that big
exhaust tip is great for drag racing".

Tim
Geoffrey S. Mendelson
2002-09-04 09:02:37 UTC
Permalink
Post by Francisco Javier Mesa-Martinez
Well when I went to Fry's I saw these things for the first time,
in the price tag they had written "Great for Overcloking!".
That's so you can actually see your CPU crash and burn. Or is it
burn and crash :-)

Geoff.
--
Geoffrey S. Mendelson
Bloomberg L.P., BFM (Israel) 2 hours ahead of London, 7 hours ahead of New York.
Tel: 972-(0)3-754-1158 Fax 972-(0)3-754-1236 Email: ***@bloomberg.com
Brian Dunbar
2002-09-04 11:00:18 UTC
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-----Original Message-----
From: Dan Sikorski [mailto:***@dansikorski.com]
<snip>
There's nothing near there that i know of that would cause such problems
(they're a RV
manufacturer). And that's not the only room in that building that has
strange problems like that.

-Dan Sikorski

Had something like that happen in an office building in Raleigh, NC. Space
had just been wired for LAN, things hummed along for a while, then one day
in September the two users on the outside wall coulldn't login. When all 3
of our pagers went off at the same time with garbage messages, and the
user's radio wouldn't pick up anything across the band but the college radio
station a few blocks away ... which had started operation after summer
hiatus ... we knew something was up.

The wiring guys had run the cable in a floor tray from the closet, then it
made a two foot kink straight up to the PC. The quickie solution was to
change the geometry of the wire run.

~brian
David L Kindred (Dave)
2002-09-04 17:42:53 UTC
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Brian> ... then one day in September the two
Brian> users on the outside wall coulldn't login. When all 3 of our
Brian> pagers went off at the same time with garbage messages, and
Brian> the user's radio wouldn't pick up anything across the band
Brian> but the college radio station a few blocks away ... which had
Brian> started operation after summer hiatus ... we knew something
Brian> was up.

We used to a have a facility within sight of the tower for what was then
WCAU, 50Kw 1210Khz. That stuff got *everywhere*. It was especially
annoying trying to debug hardware when processors used to run at about
that speed. The only good news is that we found all the "gotchas" in
the analog and voice circuits. It's not a very scientific theory, but I
think the higher the RF power the more things look like diodes :)

We also got sporadic reports that a WWVB clock we were reselling would
display the wrong time in downtown Chicago. We never believed the
reports as we never saw any errors ourselves, nor did any other
customer. One day the vendor released a tech bulletin confirming their
unit was susceptible to high RF fields. Turns out the Chicago
installation had line-of-sight to both of the buildings in Chicago with
the big TV/radio broadcast towers.
--
David L. Kindred <mailto:***@telesciences.com>
Unix Systems & Network Administrator
Telesciences, Inc. <http://www.telesciences.com>
Support: <http://support.telesciences.com>
2000 Midlantic Drive, Suite 410, Mt. Laurel, NJ 08054
Tel: +1.856.866.1000 ext. 4184
Fax: +1.856.866.0185
SMS: <mailto:***@vtext.com>
---
Scott Newell
2002-09-04 18:13:03 UTC
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Post by David L Kindred (Dave)
We also got sporadic reports that a WWVB clock we were reselling would
display the wrong time in downtown Chicago. We never believed the
Ahh, now this is something I wish they'd fix...add some redundancy (ECC,
Hamming code, parity check bits, whatever) to the WWVB datastream so that
interference would be more easily detectable. I guess simple sanity
checking (assuming you know about what time it is to begin with) would do
ok too.


newell
Andrew Weiss
2002-09-04 16:26:12 UTC
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On Wednesday, September 4, 2002, at 04:24 AM, Francisco Javier
Post by Francisco Javier Mesa-Martinez
Then we have the poor heat conductivity that those transparent cases do
have. Thus putting a thermally sensitive device, which generates a LOT
of
heat, inside a nice insulator is not a good idea IMHO. Why am I amazed
by
all this? Well when I went to Fry's I saw these things for the first
time,
in the price tag they had written "Great for Overcloking!". So the
people
who buy these transparent cases, are not only laughing at most laws of
Electrodinamics, but they are also pissing on the laws of
Thermodynamics.
I read this as "Great for Overcloaking", which would work well with a
transparent case.

-Andrew
---------------------------------------------------------------
"Pie tastes of donkey poop!... Must be bad end." -- Weebl and Bob
"I thwart your plan....with handy cannon!...how handy!" -- Weebl and Bob
Skeezics Boondoggle
2002-09-04 20:26:04 UTC
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i'm wondering if there was some unusual sunspot activity last friday,
because things are just squirelly all over. there was a power outage in
my neighborhood, which lasted several hours ("aw, crap, guess i won't be
telecommuting in my shorts today..."). so later that day at work our
netapp failed a drive, our A5200 failed a drive, our A/C unit started
leaking refrigerant, and when i got home that night and powered things
back up my son said he couldn't connect to msn messenger from his imac
anymore (yeah, i'll get right on that... :-P) and my sparcs were acting
bizarre, as reported in the post that started this thread.

as for strange interference, i can't imagine what from... the machines are
situated on a long bench; at one end there's a short dec rack with some
network gear and an old dec pdu with a neXt printer on top of that; then
bench itself holds the stack of headless ss20's, the ss4 w/monitor, and a
neXt turbo color that wasn't powered up. underneath the bench were two
4/670mp's, both currently powered down, and a pair of neXt cubes, both
powered down. i roll them to the other side of the room where they plug
into a separate pair of 20A circuits when i play with them. so the only
equipment on that pdu, and on that whole circuit, were the three sparcs,
an old hp hub, and the cisco 675. so just shuffling the machines a few
feet shouldn't have made any difference... (time to get a digital camera
so i can add to the "geek computer rooms" collection. mine's painted all
black - it really is a cave... :-)

just for grins, though, maybe i will physically move the machine and see
if that makes a difference. it sounds crazy though... it's gotta be solar
flares. ghosts. cosmic rays. karma. government conspiracy. compiler
bugs... i just need to sacrifice a chicken or a goat or a wintel box and
appease the sun gods who have cursed me... or maybe i just need a couple
of days off!
Dan Sikorski
2002-09-05 03:57:06 UTC
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Post by Skeezics Boondoggle
appease the sun gods who have cursed me... or maybe i just need a couple
of days off!
Why, that's the best idea i've heard all day!
They say that you shouldn't run away from your problems, but nobody told
me i couldn't run away from other people's problems!

-Dan Sikorski
Francisco Javier Mesa-Martinez
2002-09-05 01:33:05 UTC
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Post by Tim H.
On Tue, 3 Sep 2002 22:02:09 -0700 (PDT)
Post by Francisco Javier Mesa-Martinez
Theoretically the PC case is supposed to be a Faraday box, the fact
that it picked up the E field from a nearby powergrid would be enough
to allow you to report the manufacturer to the FCC. This is why I am
always tempted to report Fry's whenever I see one of those transparet
FeeCee cases on display....
Actually, the FCC doesn't care if your PC picks up noise, it only cares
if it broadcasts noise. THe official language is something to the
effect "(1)this device may not cause harmful interference (2) this
device must accept any interference received including interference that
may cause undesired operation. FCC doesn't regulate receivers, other
than who may listen in on what frequencies, they regulate transmitters.
As I explained in a previous post, in order to shield the internal E
fields of a device you usually have to use a device that also negates
external E fields. Hence if you have an switching electromagnetic device
that does pick up external fields, that means that your shielding is not
guaranteed to also cancel the internal radio harmonics to outside
receptors. Simple electromagnetic theory really.... That is why those
cases can not be FCC compliant, hence the owner of such device is in
theory breaking the law. But then again I am talking to a list that
includes people with class B machines, whith theoretically are also
illegal to own at home. But at least these are real machines :-).
Dan Sikorski
2002-09-05 03:58:17 UTC
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Post by Francisco Javier Mesa-Martinez
theory breaking the law. But then again I am talking to a list that
includes people with class B machines, whith theoretically are also
illegal to own at home. But at least these are real machines :-).
What's the penalty for that anyway?

-Dan Sikorski
Eric Dittman
2002-09-05 04:40:38 UTC
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Post by Dan Sikorski
Post by Francisco Javier Mesa-Martinez
theory breaking the law. But then again I am talking to a list that
includes people with class B machines, whith theoretically are also
illegal to own at home. But at least these are real machines :-).
What's the penalty for that anyway?
It isn't illegal to own them at home, they are just more likely
to interfere with other equipment, which is illegal. You can
usually fix that, though.

Speaking of FCC classifications, I've found the FCCID (if it
is listed, which it should be) can be handy in tracking down
the OEM of an item.
--
Eric Dittman
***@dittman.net
Check out the DEC Enthusiasts Club at http://www.dittman.net/
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