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O'scopes - Tek vs HP/Agilent vs LeCroy

J

joseph2k

Jan 1, 1970
0
CBFalconer said:
Nothing. It is just one of many possible causes.


An uncaught memory error can corrupt the object code you are
running, resulting in just that symptom. Once the object code has
been fouled by the memory error (for example during a disk packing
operation) it remains fouled until reloaded from the original
media. The only insurance available is to always have ECC memory,
which reduces the error chances to a negligible level. Remember
that such errors can be due to cosmic rays, and be non-repeatable.

Yes, there is value in ECC, however there are also many error sources. And
when the hardware is overly cost sensitive trimmed of protection components
not even ECC will solve the problems. There is also the difference between
correctable and uncorrectable errors with ECC.

Bottom line, ECC can help but it is not a panacea / silver bullet.
 
J

joseph2k

Jan 1, 1970
0
Stef said:
In comp.arch.embedded,


You are balancing a hardrive on top of an open case? Fine for testing
purposes, but not a long term solution. Even only leaving the case off
from your working machine introduces additional risks. There are other
solutions out there, like drive sleds and external drives. But I do
favour tapes for backup purposes. We also copy our data to other sites
through ssh tunnels as additional backup.


Why didn't you uses the extra harddisk on W3.11? This solution does not
require any software and is OS independant and fast.



True, but as stated this loss is usually much smaller than what is lost
in the average PC crash.


I use Linux exclusively on 2 of my 3 PC's and the 3th is triple-boot
W98/W2000/Fedora Core. On this PC I mostly run W2000 and I can't
remember the last time it completely crashed. It's on 24/7 but it
sometimes needs a reboot. I am not a windows fan, and I would gladly
switch to linux only if I could, but windows has improved a lot since
W3.1.

I might argue that, i had w3.1 running for well over 3 months continuously.
I could hardly keep w95 running for a day, that was NOT an improvement. W98
was an improvement over w95, but still terribly insecure. It was also a
much better adaptation to changing hardware. WinXP was an improvement
almost across the board, but not a big one. Vista is still not ready ready
for prime time, wait for SP1 to be included.
But leaving eagle running for 6 months does not sound like good
practice either. It doesn't hurt to sometimes close your program or
even perform a scheduled reboot of the machine. Leaving it running
for 6 months also means you did not update your kernel for that time
either, not good if the machine is connected to the internet.

Shutdowns are for hardware upgrades that cannot be made plug and play. I
will even consider it for a kernel changeout. Keep it modular baby.
Most people use windows only and indeed accept things from their PC that
an engineer would not accept from his analyzer. And that was the point I
was trying to make: The average loss from an analyzer crash is smaller
than that of a PC crash, but the PC crash is more accepted than the
analyzer crash, weird.

What bothers me is that i am seeing more and more MSwindows based
instruments, even from companies that did (used to) know better. There is
no possible way to ever make any MSwindows system real time, yet some
vendors are attempting it.
 
J

jasen

Jan 1, 1970
0
My biggest problem is radiation from the monitor that sometimes
clobbers a distant classical music station when I'm running DOS. I
hear blip-blips when scrolling through a page. Can't do much about
that except install an outdoor antenna and use shielded coax. The
landlord would have a fit.

if you're only hearing them while scrolling the screen (and other updates)
the blips are bus noise from inside the case, radiated from the expansion
bus that the video card is connected to. if you get them with a static
image they are coming from the video card or the monitor, a ferrite block
over the vga cable coulkd help with that.

Maybe. What about removing the covers to improve cooling, make it
easy to switch pcb's and drives, and monitor lint buildup on the cpu
heat sink and power supply inlets?

add fans to improve cooling, or use punched covers (many small holes)

Bye.
Jasen
 
R

Rich Grise

Jan 1, 1970
0
You just looking for an excuse to fire up an air compressor with a
blow-off nozzle. I know how much fun those are! :) (And it really is
amazing how much dust comes out of old PCs...)

I sometimes worry when I spin those fans with compressed air - am I
generating dangerous voltages? =:-O

Thanks
Rich
 
M

Mike Monett

Jan 1, 1970
0
if you're only hearing them while scrolling the screen (and other
updates) the blips are bus noise from inside the case, radiated
from the expansion bus that the video card is connected to. if you
get them with a static image they are coming from the video card
or the monitor, a ferrite block over the vga cable coulkd help
with that.

I don't think so. The monitor switches scan frequency when going
from Windows to DOS. There is something in the monitor that creates
extra noise when scrolling. There is no noise on a static display.

There is nothing in the cable that knows what scan rate the monitor
is using at the moment. The blips do not occur at 1024X768, only at
640X480.

However, moving to a 5/8 wave vertical completely solved the
problem. There is no more noise on any frequency through the entire
FM band, even though the vertical is only a foot from the monitor.

This problem has plagued me for several years, and this is the first
time I found something that worked. Than you very much for
mentioning EMI in an earlier post. For some reason that triggered
the idea to try a different approach - and it worked!
add fans to improve cooling, or use punched covers (many small
holes)

That doesn't help when switching cards or checking for lint buildup.
Or discovering the cpu fan is seizing and ready to fail.

Obviously, if you are in an environment where screwdrivers, paper
clips, solder balls and coffee is flying through the air, you need
some protection for your computers. But I have a very benign
environment. I have no visitors to worry about, and everything is
open the way I like. The covers on computers just slow me down and
impede creativity. And that's a sin.

Do you know how difficult it is to replace the covers on a computer
after fixing it? I just spent 1/2 hr fooling with the covers on my
landlord's computer. What a pain. I'll leave mine off, thank you
very much:)

I do have a fan salvaged from the freezer section in a fridge that
mounts on the side of the computer during warm spells. It runs very
quiet and helps reduce crashes on hot days. But obviously it's time
to upgrade all the computers in the lab. And part of the new spec
will be reliable operation at elevated temperature:)

Regards,

Mike Monett

Antiviral, Antibacterial Silver Solution:
http://silversol.freewebpage.org/index.htm
SPICE Analysis of Crystal Oscillators:
http://silversol.freewebpage.org/spice/xtal/clapp.htm
Noise-Rejecting Wideband Sampler:
http://www3.sympatico.ca/add.automation/sampler/intro.htm
 
J

jasen

Jan 1, 1970
0
I don't think so. The monitor switches scan frequency when going
from Windows to DOS. There is something in the monitor that creates
extra noise when scrolling. There is no noise on a static display.

I had that problem and found that securing the case solved it.
There's nothing the monitor does differently when displaying a scrolling
or static image that's likely to cause radiated noise... OTOH all the
updates going over the expansion bus will radiate during scrolling. and
there could easily be 4000 active bus cycles per line scrolled.
That doesn't help when switching cards or checking for lint buildup.
Or discovering the cpu fan is seizing and ready to fail.

the punched cases are effectively see-through, but yeah you still have
to open them, takes anout 2 minutes to move the cables out of the way,
undo the 2 thumbscrews and slide the panel back a little to disengage it.
after fixing it? I just spent 1/2 hr fooling with the covers on my
landlord's computer. What a pain. I'll leave mine off, thank you
very much:)

yeah, some are like that.

Bye.
Jasen
 
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