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Changing PCI cards without switching off?

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December 23, 2004 8:55:10 PM

Archived from groups: uk.comp.homebuilt,alt.comp.hardware,alt.comp.hardware.pc-homebuilt (More info?)

I usually switch off my PC before I change a PCI card but a recent
case I wanted to remove a modem card, then inspect the markings and
then restore it in the PC.

If I don't switch off the PC then what sort of damage might I cause?
December 23, 2004 9:02:48 PM

Archived from groups: uk.comp.homebuilt,alt.comp.hardware,alt.comp.hardware.pc-homebuilt (More info?)

"Franklin" <no_thanks@mail.com> wrote in message
news:95C8B6498501E71F3M4@130.133.1.4...
>I usually switch off my PC before I change a PCI card but a recent
> case I wanted to remove a modem card, then inspect the markings and
> then restore it in the PC.
>
> If I don't switch off the PC then what sort of damage might I cause?

Luck of the draw....You'll probably get away with it once.

You should switch off at the mains too. Front button isn't enough - the PCI
slots are still powered.
December 23, 2004 9:03:55 PM

Archived from groups: uk.comp.homebuilt,alt.comp.hardware,alt.comp.hardware.pc-homebuilt (More info?)

Franklin wrote:
> I usually switch off my PC before I change a PCI card but a recent
> case I wanted to remove a modem card, then inspect the markings and
> then restore it in the PC.
>
> If I don't switch off the PC then what sort of damage might I cause?

It is not certain that you will do any damage, but you certainly won't
do any good. If you are hoping to remove it and replace it and still
have the modem recognized as it was before you removed it, I don't
believe that will happen. Your modem has an IRQ, and I believe the
computer keeps polling it. Once it fails to receive and acknowledgment,
the only way to get it is to reboot. Again, I am not 100% sure of this,
but I believe I am correct.

It would seem to me therefore, that since you MIGHT damage the card and
it will not keep the modem as hardware it recognized upon boot up, there
is nothing but disadvantages to the idea.
Related resources
Anonymous
a b B Homebuilt system
December 23, 2004 9:25:08 PM

Archived from groups: uk.comp.homebuilt,alt.comp.hardware,alt.comp.hardware.pc-homebuilt (More info?)

"chris" <chris@ntlworld.com> wrote:
>"Franklin" <no_thanks@mail.com> wrote in message

>>I usually switch off my PC before I change a PCI card but a recent
>> case I wanted to remove a modem card, then inspect the markings and
>> then restore it in the PC.
>>
>> If I don't switch off the PC then what sort of damage might I cause?
>
>Luck of the draw....You'll probably get away with it once.
>You should switch off at the mains too. Front button isn't enough - the PCI
>slots are still powered.

<rolls eyes, looks up at the newsgroups field>

Yup, it's crossposted.





>
>
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>Newsgroups: uk.comp.homebuilt,alt.comp.hardware,alt.comp.hardware.pc-homebuilt
>References: <95C8B6498501E71F3M4@130.133.1.4>
>Subject: Re: Changing PCI cards without switching off?
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Anonymous
a b B Homebuilt system
December 23, 2004 10:10:40 PM

Archived from groups: uk.comp.homebuilt,alt.comp.hardware,alt.comp.hardware.pc-homebuilt (More info?)

On Thu, 23 Dec 2004 17:55:10 GMT, Franklin
<no_thanks@mail.com> wrote:

>I usually switch off my PC before I change a PCI card but a recent
>case I wanted to remove a modem card, then inspect the markings and
>then restore it in the PC.
>
>If I don't switch off the PC then what sort of damage might I cause?

It'll lock up the PC for one thing, just turn it off first
and unplug it.
December 23, 2004 10:15:14 PM

Archived from groups: uk.comp.homebuilt,alt.comp.hardware,alt.comp.hardware.pc-homebuilt (More info?)

"Franklin" <no_thanks@mail.com> wrote in message
news:95C8B6498501E71F3M4@130.133.1.4...
>I usually switch off my PC before I change a PCI card but a recent
> case I wanted to remove a modem card, then inspect the markings and
> then restore it in the PC.
>
> If I don't switch off the PC then what sort of damage might I cause?

Why even consider risking your PC?
Just do it properly and power down, unplug and take the card out.

SteveH
Anonymous
a b B Homebuilt system
December 23, 2004 11:31:09 PM

Archived from groups: uk.comp.homebuilt,alt.comp.hardware,alt.comp.hardware.pc-homebuilt (More info?)

"Franklin" <no_thanks@mail.com> wrote in message
news:95C8B6498501E71F3M4@130.133.1.4...
> I usually switch off my PC before I change a PCI card but a recent
> case I wanted to remove a modem card, then inspect the markings and
> then restore it in the PC.
>
> If I don't switch off the PC then what sort of damage might I cause?

Do you turn the BACK of the PC off (or unplug the power?) If not you still
have power on the PCI slots and can fry your mainboard.
December 24, 2004 2:17:39 AM

Archived from groups: uk.comp.homebuilt,alt.comp.hardware,alt.comp.hardware.pc-homebuilt (More info?)

"Ken" <user@domain.invalid> schreef in bericht
news:fMDyd.1148917$Gx4.112837@bgtnsc04-news.ops.worldnet.att.net...
> Franklin wrote:
>> I usually switch off my PC before I change a PCI card but a recent case I
>> wanted to remove a modem card, then inspect the markings and then restore
>> it in the PC.
>>
>> If I don't switch off the PC then what sort of damage might I cause?
>
> It is not certain that you will do any damage, but you certainly won't do
> any good. If you are hoping to remove it and replace it and still have
> the modem recognized as it was before you removed it, I don't believe that
> will happen. Your modem has an IRQ, and I believe the computer keeps
> polling it.

There is one reason why hardware interrupts were invented, and that is so
that polling wouldn't be necessary anymore.
But apart from that, You are very right saying it would be very unwise to do
what OP wants to do.

Greetings,
Rene
Anonymous
a b B Homebuilt system
December 24, 2004 3:18:41 AM

Archived from groups: uk.comp.homebuilt,alt.comp.hardware,alt.comp.hardware.pc-homebuilt (More info?)

Arcing and burning out the motherboard. Nothing serious...

--
DaveW



"Franklin" <no_thanks@mail.com> wrote in message
news:95C8B6498501E71F3M4@130.133.1.4...
>I usually switch off my PC before I change a PCI card but a recent
> case I wanted to remove a modem card, then inspect the markings and
> then restore it in the PC.
>
> If I don't switch off the PC then what sort of damage might I cause?
Anonymous
a b B Homebuilt system
December 24, 2004 3:30:17 AM

Archived from groups: uk.comp.homebuilt,alt.comp.hardware,alt.comp.hardware.pc-homebuilt (More info?)

"Franklin" <no_thanks@mail.com> wrote in message
news:95C8B6498501E71F3M4@130.133.1.4...
>I usually switch off my PC before I change a PCI card but a recent
> case I wanted to remove a modem card, then inspect the markings and
> then restore it in the PC.
>
> If I don't switch off the PC then what sort of damage might I cause?

you might get away without doing any damage, but it will almost certainly
cause a crash so you'll have to restart anyway...
Anonymous
a b B Homebuilt system
December 24, 2004 8:33:25 AM

Archived from groups: uk.comp.homebuilt,alt.comp.hardware,alt.comp.hardware.pc-homebuilt (More info?)

There are a lot of people warning that removing a PCI card from a
running machine will cause damage. While I don't intend to do this, has
anybody actually tested removing and inserting PCI cards in running
machines, or is this just the Standard Warning? (Easy enough to test
these days, with older machine being scrapped because you can't give
them away.) I would hazard a guess that it might actually not cause
damage in most, or all, cases.

Certainly there are some flavours of PCI designed for hot-swapping.
Anonymous
a b B Homebuilt system
December 24, 2004 8:33:26 AM

Archived from groups: alt.comp.hardware.pc-homebuilt (More info?)

Michael Salem wrote:

> There are a lot of people warning that removing a PCI card from a
> running machine will cause damage. While I don't intend to do this, has
> anybody actually tested removing and inserting PCI cards in running
> machines, or is this just the Standard Warning? (Easy enough to test
> these days, with older machine being scrapped because you can't give
> them away.) I would hazard a guess that it might actually not cause
> damage in most, or all, cases.
>
> Certainly there are some flavours of PCI designed for hot-swapping.

In one of my recent googling cram sessions, I think I did run across
something about pci hotswap, but I didn't go into the link -- haha, this is
how rumors get started (and perhaps innovation implemented).

I bumped my modem once, and the machine rebooted.

Bryan
Anonymous
a b B Homebuilt system
December 24, 2004 9:38:36 AM

Archived from groups: uk.comp.homebuilt,alt.comp.hardware,alt.comp.hardware.pc-homebuilt (More info?)

Michael Salem:

> has anybody actually tested removing and inserting PCI cards in
> running machines

I don't remember the exact circumstances but I was picking a machine up to
move it and set it down too hard and it locked up. Turned out one of the
PCI cards was loose.

I accidently touched a video card once while the machine was running and
the machine locked up. When I rebooted I eventually discovered the video
card would lock up the computer when it tried to render 3D graphics (video
games).

--
Mac Cool
Anonymous
a b B Homebuilt system
December 24, 2004 12:07:20 PM

Archived from groups: uk.comp.homebuilt,alt.comp.hardware,alt.comp.hardware.pc-homebuilt (More info?)

No one has provided the proper technical answer. First
removing. Damage most easily caused when a card uses multiple
voltages. Simply breaking a ground connection before other
voltages then causes excessive or reversed voltages on some PN
(semiconductor) junctions is excess of spec. IOW it destroys
transistors.

Busses are designed to be 'hot popped'. There is even a PCI
standard for hot popping. First and foremost, every card must
be designed so the ground pin is always 'last to break and
first to make'. Then other complications only make things
worse.

Now for connecting. Same problem exists for power on.
Suppose the 5 volts arrives before 12 volts. Now junctions
that saw +7 volts (difference between 12 and 5 volt busses)
are instead powered by -5 volts. Not good. Furthermore,
there is a slight 'power on' current surge. It does not exist
during normal 'power on' because power cycling the power
supply causes such a slow and gentle voltage change. But 'hot
popping' a card into a hot buss means a sudden jolt of
current. This can cause data errors (also known as computer
crash) and may even cause hardware damage to PCI pins not
rated for so much current or performing as a switch. Devices
that switch power on and off must be specially designed to do
so. PCI pins are not designed for switching. Numerous
reasons why cards that are hot popped also include current
limiter circuits for hot popping.

These are only a sample in a long line of reasons that make
'hot popping' designs so complicated. Learn about the 'hot
pop' versions of PCI. It is a kludge solution, but it
demonstrates omplexity to avoid hardware damage. Ssolid
technical reasons demonstrate why 'hot popping' is hardware
destructive.

Franklin wrote:
> I usually switch off my PC before I change a PCI card but a recent
> case I wanted to remove a modem card, then inspect the markings and
> then restore it in the PC.
>
> If I don't switch off the PC then what sort of damage might I cause?
Anonymous
a b B Homebuilt system
December 24, 2004 12:19:13 PM

Archived from groups: uk.comp.homebuilt,alt.comp.hardware,alt.comp.hardware.pc-homebuilt (More info?)

"Michael Salem" <a$-b$1@ms3.org.uk> wrote in message
news:MPG.1c35ba802714a2c8989871@News.individual.NET...
> There are a lot of people warning that removing a PCI card from a
> running machine will cause damage. While I don't intend to do this, has
> anybody actually tested removing and inserting PCI cards in running
> machines, or is this just the Standard Warning? (Easy enough to test
> these days, with older machine being scrapped because you can't give
> them away.) I would hazard a guess that it might actually not cause
> damage in most, or all, cases.
>
> Certainly there are some flavours of PCI designed for hot-swapping.
its the mother board that determines a hot swappable slot I had a brief
course on severs and some had a hot swap pci slots with a led to show the
difference between a live powered slot and a pci slot that was powered down
and as for doing it to a powered system you can fry a mother board I
dismantled a pc powered off with out switching of the psu and it fried the
mother board its luck of the draw which pins on the card make contact first
Anonymous
a b B Homebuilt system
December 24, 2004 1:08:21 PM

Archived from groups: uk.comp.homebuilt,alt.comp.hardware,alt.comp.hardware.pc-homebuilt (More info?)

"Michael Salem" <a$-b$1@ms3.org.uk> wrote in message
news:MPG.1c35ba802714a2c8989871@News.individual.NET...
> There are a lot of people warning that removing a PCI card from a
> running machine will cause damage. While I don't intend to do this, has
> anybody actually tested removing and inserting PCI cards in running
> machines, or is this just the Standard Warning? (Easy enough to test
> these days, with older machine being scrapped because you can't give
> them away.) I would hazard a guess that it might actually not cause
> damage in most, or all, cases.

I think the chance is significant. PS/2 keyboard/mouse connectors are not
usually designed to be hot plugged, and I've certainly heard of apparent
damage to motherboards arising from trying to do that. Given the fact PCI is
internal, it's even less likely any kind of protection will exist.

But the possibility of damage is a moot point: every time I've knocked a
loose PCI card (physical shock to the PC, or catching some protruding
connector/attached cable), the PC has crashed. If removing a card is
practically guaranteed to crash the PC (and it would seem so), then you
might as well turn it off anyway.

Alex
Anonymous
a b B Homebuilt system
December 24, 2004 1:12:29 PM

Archived from groups: uk.comp.homebuilt,alt.comp.hardware,alt.comp.hardware.pc-homebuilt (More info?)

"Kevin R" <dontemailme@ntlworld.com> wrote in message
news:laRyd.964$tJ5.778@newsfe3-win.ntli.net...
[snip]
> its luck of the draw which pins on the card make contact first

Hmm, I have a feeling that things sometimes object (destructively) to having
signals connected before power. Perhaps that's the problem.

Alex
Anonymous
a b B Homebuilt system
December 24, 2004 1:37:59 PM

Archived from groups: uk.comp.homebuilt,alt.comp.hardware,alt.comp.hardware.pc-homebuilt (More info?)

"Michael Salem" <a$-b$1@ms3.org.uk> wrote in message
news:MPG.1c35ba802714a2c8989871@News.individual.NET...
> There are a lot of people warning that removing a PCI card from a
> running machine will cause damage. While I don't intend to do this, has
> anybody actually tested removing and inserting PCI cards in running
> machines, or is this just the Standard Warning? (Easy enough to test
> these days, with older machine being scrapped because you can't give
> them away.) I would hazard a guess that it might actually not cause
> damage in most, or all, cases.
>
> Certainly there are some flavours of PCI designed for hot-swapping.

No but i've tried it with an old slot processor in a knackered old machine.
still worked after...
Anonymous
a b B Homebuilt system
December 24, 2004 1:47:34 PM

Archived from groups: uk.comp.homebuilt,alt.comp.hardware,alt.comp.hardware.pc-homebuilt (More info?)

Alex Fraser wrote:
>
> "Kevin R" <dontemailme@ntlworld.com> wrote in message
> news:laRyd.964$tJ5.778@newsfe3-win.ntli.net...
> [snip]
> > its luck of the draw which pins on the card make contact first
>
> Hmm, I have a feeling that things sometimes object (destructively) to having
> signals connected before power. Perhaps that's the problem.
>
> Alex


Exactly! Proper 'external' cards such as memory cards or PCMCIA are
engineered such that power is connected before signal.
Anonymous
a b B Homebuilt system
December 24, 2004 2:33:26 PM

Archived from groups: uk.comp.homebuilt,alt.comp.hardware,alt.comp.hardware.pc-homebuilt (More info?)

I wrote:

> > There are a lot of people warning that removing a PCI card from a
> > running machine will cause damage. While I don't intend to do this, has
> > anybody actually tested removing and inserting PCI cards in running
> > machines, or is this just the Standard Warning? (Easy enough to test
> > these days, with older machine being scrapped because you can't give
> > them away.) I would hazard a guess that it might actually not cause
> > damage in most, or all, cases.

Alex Fraser responded:

> But the possibility of damage is a moot point: every time I've knocked a
> loose PCI card (physical shock to the PC, or catching some protruding
> connector/attached cable), the PC has crashed.

That's useful to know.

> If removing a card is
> practically guaranteed to crash the PC (and it would seem so), then you
> might as well turn it off anyway.

Yes -- I don't actually advocate hot-swapping standard PCI cards, but
was interested to find if there was any actual information rather than
just (eminently sensible) warnings about the consequences. I note that
nobody has yet reported damage due specifically to hot-plugging PCI
cards. If I remember and have time, I might do some tests the next time
I scrap a working machine.

By the way, even if this sort of thing doesn't seem to do damage, it's
not a good idea without longer-term testing to ensure that circuitry
doesn't suffer non-fatal damage leading to unreliable operation.

I was prompted to ask this question remembering a book (The Birth of a
New Machine?) about a computer developed under time pressure by DEC (?).
What struck me was that they regularly hot-swapped just about any
socketed chip (which is always considered to be something you should
absolutely never do) with no trouble. Computers had a lot of chips in
those days, rather than the few large-scale integrated chips used now.

Best wishes,
--
Michael Salem
Anonymous
a b B Homebuilt system
December 24, 2004 3:52:20 PM

Archived from groups: uk.comp.homebuilt,alt.comp.hardware,alt.comp.hardware.pc-homebuilt (More info?)

In article Michael Salem says...
> There are a lot of people warning that removing a PCI card from a
> running machine will cause damage. While I don't intend to do this, has
> anybody actually tested removing and inserting PCI cards in running
> machines, or is this just the Standard Warning? (Easy enough to test
> these days, with older machine being scrapped because you can't give
> them away.) I would hazard a guess that it might actually not cause
> damage in most, or all, cases.
>
Actually it can toast the PCI controller and any other car on the PCI
bus.

> Certainly there are some flavours of PCI designed for hot-swapping.
>
And you know you've got them because you'll certainly pay for them.

--
Conor

An imperfect plan executed violently is far superior to a perfect plan.
-- George Patton
Anonymous
a b B Homebuilt system
December 24, 2004 4:20:02 PM

Archived from groups: uk.comp.homebuilt,alt.comp.hardware,alt.comp.hardware.pc-homebuilt (More info?)

Conor wrote about hot-swapping PCI cards:

> Actually it can toast the PCI controller and any other card on the PCI
> bus.

Have you ever known a case where this has actually happened? I'm not
trying to say that it can't happen, merely trying to find specific
instances rather than warnings not based on actual experience.

Even if nobody has known it to cause damage, I don't advocate the
practice.
Anonymous
a b B Homebuilt system
December 24, 2004 4:49:55 PM

Archived from groups: uk.comp.homebuilt,alt.comp.hardware,alt.comp.hardware.pc-homebuilt (More info?)

Michael Salem wrote:
>
> Conor wrote about hot-swapping PCI cards:
>
> > Actually it can toast the PCI controller and any other card on the PCI
> > bus.
>
> Have you ever known a case where this has actually happened? I'm not
> trying to say that it can't happen, merely trying to find specific
> instances rather than warnings not based on actual experience.

It is just common sense. If the lines are connected in no particular
order, then you could possibly connect the positive pole of the power
and a signal line before the negative power pole was connected. That
could then easily fry circuits between the signal and the positive pole.

> Even if nobody has known it to cause damage, I don't advocate the
> practice.

Don't even think about it...
Anonymous
a b B Homebuilt system
December 24, 2004 6:06:37 PM

Archived from groups: uk.comp.homebuilt,alt.comp.hardware,alt.comp.hardware.pc-homebuilt (More info?)

Johannes H Andersen wrote:
>
> Michael Salem wrote:
> >
> > Conor wrote about hot-swapping PCI cards:
> >
> > > Actually it can toast the PCI controller and any other card on the PCI
> > > bus.
> >
> > Have you ever known a case where this has actually happened? I'm not
> > trying to say that it can't happen, merely trying to find specific
> > instances rather than warnings not based on actual experience.
>
> It is just common sense. If the lines are connected in no particular
> order, then you could possibly connect the positive pole of the power
> and a signal line before the negative power pole was connected. That
> could then easily fry circuits between the signal and the positive pole.

Everybody but everybody just knows that it will cause damage (for
perfectly good technical reasons) but nobody at all seems to have come
across an instance where damage has actually happened!

I have seen plenty of things happen that are supposed to cause damage,
and haven't. I would expect (but haven't checked) that the pinout of PCI
devices is designed so that it is likely that contacts are made and
broken in a safe order when cards are plugged in and out. Also, the
circuitry and components used may be more forgiving than they could be.

Things that, to my surprise, did not cause damage include removing
memory DIMMs from a powered-up (oops) motherboard; connecting an 18V
"wall-wart" PSU to a 5V router (I don't remember if polarity was
correct, inverted, or ac); inserting connectors and chips the wrong way
round. And of course, routinely inserting and removing DIL chips from a
running computer, as done by a company developing a new computer in the
days of DTL and TTL (as mentioned in an earlier posting of mine).

Another thing that I would expect to cause damage is random shorts to
earth; for example, via mounting pillars on an incorrectly mounted
motherboard. But no, remove the short and it all springs into life.

While bad practice shouldn't be encouraged, you often get away with
mistakes.

Best wishes,
--
Michael Salem
Anonymous
a b B Homebuilt system
December 24, 2004 7:13:22 PM

Archived from groups: uk.comp.homebuilt,alt.comp.hardware,alt.comp.hardware.pc-homebuilt (More info?)

Michael Salem <a$-b$1@ms3.org.uk> wrote:

....

>Yes -- I don't actually advocate hot-swapping standard PCI cards, but
>was interested to find if there was any actual information rather than
>just (eminently sensible) warnings about the consequences. I note that
>nobody has yet reported damage due specifically to hot-plugging PCI
>cards.

I read that some have.

If you want electrical/electronic explanations, maybe you should post
to (sci.electronics...) groups.
Anonymous
a b B Homebuilt system
December 24, 2004 7:17:08 PM

Archived from groups: uk.comp.homebuilt,alt.comp.hardware,alt.comp.hardware.pc-homebuilt (More info?)

Michael Salem <a$-b$1@ms3.org.uk> wrote:

>Johannes H Andersen wrote:
>>
>> Michael Salem wrote:
>> >
>> > Conor wrote about hot-swapping PCI cards:
>> >
>> > > Actually it can toast the PCI controller and any other card
>> > > on the PCI bus.
>> >
>> > Have you ever known a case where this has actually happened?
>> > I'm not trying to say that it can't happen, merely trying to
>> > find specific instances rather than warnings not based on
>> > actual experience.
>>
>> It is just common sense. If the lines are connected in no
>> particular order, then you could possibly connect the positive
>> pole of the power and a signal line before the negative power
>> pole was connected. That could then easily fry circuits between
>> the signal and the positive pole.
>
>Everybody but everybody just knows that it will cause damage (for
>perfectly good technical reasons) but nobody at all seems to have
>come across an instance where damage has actually happened!

That makes at least the third time you have said that in this
thread. And that disagrees with what I have read. Maybe your news
server is incomplete?

Again, if you want electrical/electronic information, you can get
that in a (sci.electronics...) discussion group. When you do, please
feel free to post your enlightenment back here.

Good luck.
Anonymous
a b B Homebuilt system
December 24, 2004 7:17:24 PM

Archived from groups: uk.comp.homebuilt,alt.comp.hardware,alt.comp.hardware.pc-homebuilt (More info?)

Michael Salem wrote:
>
[...]
>
> While bad practice shouldn't be encouraged, you often get away with
> mistakes.

And sometimes not so lucky. As badly made 3.5" -> 2.5" laptop disk
drive connector once caught the chassis and short circuited the power
wires. The sudden pulse fried the circuit board on my laptop drive!
Anonymous
a b B Homebuilt system
December 24, 2004 7:32:31 PM

Archived from groups: uk.comp.homebuilt,alt.comp.hardware,alt.comp.hardware.pc-homebuilt (More info?)

w_tom <w_tom1@hotmail.com> wrote:

> No one has provided the proper technical answer.

The original cross posted question has been answered just fine.

> Busses are designed to be 'hot popped'.

http://tinyurl.com/666mp

(http://groups-beta.google.com/groups?as_epq=hot%20poppe...
e=images&as_ugroup=Sci.electronics*&as_scoring=d&lr=lang_en&
num=100&hl=en)

There is no such thing as "hot popped".

Once again, w_tom helps prove why posting off-topic can lead to
problems.

w_tom, please take your engineering degree to a (sci.electronics...)
group. I enjoy the reading.
















There is even a PCI
>standard for hot popping. First and foremost, every card must
>be designed so the ground pin is always 'last to break and
>first to make'. Then other complications only make things
>worse.
>
> Now for connecting. Same problem exists for power on.
>Suppose the 5 volts arrives before 12 volts. Now junctions
>that saw +7 volts (difference between 12 and 5 volt busses)
>are instead powered by -5 volts. Not good. Furthermore,
>there is a slight 'power on' current surge. It does not exist
>during normal 'power on' because power cycling the power
>supply causes such a slow and gentle voltage change. But 'hot
>popping' a card into a hot buss means a sudden jolt of
>current. This can cause data errors (also known as computer
>crash) and may even cause hardware damage to PCI pins not
>rated for so much current or performing as a switch. Devices
>that switch power on and off must be specially designed to do
>so. PCI pins are not designed for switching. Numerous
>reasons why cards that are hot popped also include current
>limiter circuits for hot popping.
>
> These are only a sample in a long line of reasons that make
>'hot popping' designs so complicated. Learn about the 'hot
>pop' versions of PCI. It is a kludge solution, but it
>demonstrates omplexity to avoid hardware damage. Ssolid
>technical reasons demonstrate why 'hot popping' is hardware
>destructive.
>
>Franklin wrote:
>> I usually switch off my PC before I change a PCI card but a recent
>> case I wanted to remove a modem card, then inspect the markings
and
>> then restore it in the PC.
>>
>> If I don't switch off the PC then what sort of damage might I
cause?
>
Anonymous
a b B Homebuilt system
December 24, 2004 7:32:32 PM

Archived from groups: uk.comp.homebuilt,alt.comp.hardware,alt.comp.hardware.pc-homebuilt (More info?)

My dear sir: Do you ever first learn what you are reading
before posting like an business school graduate? Shame on
you. Cited in
http://tinyurl.com/666mp
are discussions about voltages tripping out. For example:
> I did have 25"'ers pop their HOTs because of that L14401. Even
> my CTC185 19" set came in HOT popped because of that infamous
> "L14401".
Why are voltages in a monitor relevant to hot popping PCI
peripheral cards? Shame on you for posting only because
another discussion used the same phrase. You are an expert
only because you can do Google searches? First you must
comprehend the science behind that Google text. Your post
demonstrates why a newsgroup poster again earns bad
credibility. News flash - hot popping is permitted by some
busses and not in others. Hot popping exists.

Properly posted with appropriate technical reasons are why
PCI cards cannot be hot popped. A post that every technically
knowledgeable computer assembler would understand and
appreciate. Unfortunately it is too complex for John Doe who
wants it posted to other newsgroups.

Only the naive John Doe would believe hot popping does not
exist because he could not find it in Google. As Bugs Bunny
once said, "What a Maroon".

John Doe wrote:
> w_tom <w_tom1@hotmail.com> wrote:
>> No one has provided the proper technical answer.
>
> The original cross posted question has been answered just fine.
>
>> Busses are designed to be 'hot popped'.
>
> http://tinyurl.com/666mp
> ...
> There is no such thing as "hot popped".
>
> Once again, w_tom helps prove why posting off-topic can lead to
> problems.
>
> w_tom, please take your engineering degree to a (sci.electronics...)
> group. I enjoy the reading.
Anonymous
a b B Homebuilt system
December 24, 2004 7:57:16 PM

Archived from groups: uk.comp.homebuilt,alt.comp.hardware,alt.comp.hardware.pc-homebuilt (More info?)

"Michael Salem" <a$-b$1@ms3.org.uk> wrote in message
news:MPG.1c35ba802714a2c8989871@News.individual.NET...
> There are a lot of people warning that removing a PCI card from a
> running machine will cause damage. While I don't intend to do this, has
> anybody actually tested removing and inserting PCI cards in running
> machines, or is this just the Standard Warning? (Easy enough to test
> these days, with older machine being scrapped because you can't give
> them away.) I would hazard a guess that it might actually not cause
> damage in most, or all, cases.

Heck, I've pulled BIOS chips out of a running PC. There's a good chance
something will be damaged when disconnecting a card or chip from a powered
up (plugged in!) PC.

Just DON'T do it unless you have no other alternative!!!
Anonymous
a b B Homebuilt system
December 24, 2004 8:19:28 PM

Archived from groups: uk.comp.homebuilt,alt.comp.hardware,alt.comp.hardware.pc-homebuilt (More info?)

"Michael Salem" <a$-b$1@ms3.org.uk> wrote in message
news:MPG.1c360ed65ec862b5989874@News.individual.NET...
> Alex Fraser responded:
>
> > But the possibility of damage is a moot point: every time I've knocked
> > a loose PCI card (physical shock to the PC, or catching some
> > protruding connector/attached cable), the PC has crashed.

I probably should have added that this hasn't happened a huge number of
times, perhaps a dozen or so, but other people have had identical
experiences. Just to be clear, the PC crashing is the only apparent effect.

> By the way, even if this sort of thing doesn't seem to do damage, it's
> not a good idea without longer-term testing to ensure that circuitry
> doesn't suffer non-fatal damage leading to unreliable operation.

Indeed, that or some kind of degradation that ultimately leads to failure.

Alex
Anonymous
a b B Homebuilt system
December 24, 2004 8:19:29 PM

Archived from groups: uk.comp.homebuilt,alt.comp.hardware,alt.comp.hardware.pc-homebuilt (More info?)

Doing something is just fine only because it did not cause
failures previously? What kind of logic is that? Some
darkening of the first O'ring was the only apparent effect
when launching a space shuttle in sub freezing weather. That
proved, beyond a doubt to every bean counter type, that the
shuttle could launch in sub freezing weather. At least until
Challenger exploded. Then Morton Thiokol almost got away with
the coverup. Every engineer said don't launch. They understood
one must first know why it does not cause failure. The 'why'
says PCI card damage can be created by hot popping - and not
just system crashes.

Yes hot popping peripheral cards will not always cause
hardware damage. Damage is downright infrequent since many IO
cards do not use multiple voltages and draw very little
current. But explained in technical detail are examples of
how a PCI card can be damaged AND how I suspect one may have
been damaged. It is rare, but it does happen when it should.

Why does a PCI standard for a unique PCI bus exist so that
cards can be hot popped? So that system hardware could be
reconfigured without interrupting system operation. A special
PCI bus that requires additional circuitry and LEDs on the
motherboard. Point is that a special standard exists to avoid
PCI hardware damage because standard PCI buss cannot be 'hot
popped'. The basic PCI bus does not permit hot popping. Even
if damage does not immediately occur, over stress may cause
PCI card failure later. Posted previously was why hot popping
causes PCI damage to happen and the conditions that make this
failure possible.

Even the USB standard has special hardware and provisions so
that USB devices can be 'hot popped'. Connecting and
disconnecting devices from a buss requires special hardware so
that hot popping causes neither system crashes nor hardware
damage. System crashing alone is not the only symptom.

Alex Fraser wrote:
> I probably should have added that this hasn't happened a huge number
> of times, perhaps a dozen or so, but other people have had identical
> experiences. Just to be clear, the PC crashing is the only apparent
> effect.
>
>> By the way, even if this sort of thing doesn't seem to do damage,
>> it's not a good idea without longer-term testing to ensure that
>> circuitry doesn't suffer non-fatal damage leading to unreliable
>> operation.
>
> Indeed, that or some kind of degradation that ultimately leads to
> failure.
Anonymous
a b B Homebuilt system
December 24, 2004 10:41:59 PM

Archived from groups: uk.comp.homebuilt,alt.comp.hardware,alt.comp.hardware.pc-homebuilt (More info?)

hot swapped a modem once [was stressed, rushing - was working at a firm and
they really piled on the pressure]

hot swapped an ambient modem for a connexant.

Realised my mistake, rebooted the system, the system detected the new modem
and worked fine :-)

The ambient modem worked fine in another system too.

I wouldnt recommend trying it though....


--
No66y©
Those who find they're touched by madness
Sit down next to me

Reply to address is a spam trap.
Use no66y [at] breathe [dot] com
December 25, 2004 12:02:43 AM

Archived from groups: uk.comp.homebuilt,alt.comp.hardware,alt.comp.hardware.pc-homebuilt (More info?)

Rene wrote:
> "Ken" <user@domain.invalid> schreef in bericht
> news:fMDyd.1148917$Gx4.112837@bgtnsc04-news.ops.worldnet.att.net...
>
>>Franklin wrote:
>>
>>>I usually switch off my PC before I change a PCI card but a recent case I
>>>wanted to remove a modem card, then inspect the markings and then restore
>>>it in the PC.
>>>
>>>If I don't switch off the PC then what sort of damage might I cause?
>>
>>It is not certain that you will do any damage, but you certainly won't do
>>any good. If you are hoping to remove it and replace it and still have
>>the modem recognized as it was before you removed it, I don't believe that
>>will happen. Your modem has an IRQ, and I believe the computer keeps
>>polling it.
>
>
> There is one reason why hardware interrupts were invented, and that is so
> that polling wouldn't be necessary anymore.
> But apart from that, You are very right saying it would be very unwise to do
> what OP wants to do.
>
> Greetings,
> Rene
>
>
>

I don't want to kick a dead horse, but I must ask you a question: Are
you saying then that assuming no damage was done in removing and
re-installing the PCI modem with power on, that the system would still
think it had the same modem as before it was removed? I have not pulled
many such cards, but I seem to recall that even disconnecting a HD from
the IDE bus caused the drive to be removed from the hardware it thought
it had. Needless to say I did not do this often enough to be certain of
the outcome. I look forward to your reply.
Anonymous
a b B Homebuilt system
December 25, 2004 12:02:44 AM

Archived from groups: uk.comp.homebuilt,alt.comp.hardware,alt.comp.hardware.pc-homebuilt (More info?)

On Fri, 24 Dec 2004 13:02:43 -0800, Ken <user@domain.invalid> wrote:


>
> I don't want to kick a dead horse, but I must ask you a question: Are
>you saying then that assuming no damage was done in removing and
>re-installing the PCI modem with power on, that the system would still
>think it had the same modem as before it was removed? I have not pulled
>many such cards, but I seem to recall that even disconnecting a HD from
>the IDE bus caused the drive to be removed from the hardware it thought
>it had. Needless to say I did not do this often enough to be certain of
>the outcome. I look forward to your reply.


Ken -

Why don't you tell us the "end result" you're after here - maybe we
can help you get it. It seems like you're trying to accomplish
something (troubleshooting a modem problem?), and are going about it
the wrong way.


M
Anonymous
a b B Homebuilt system
December 25, 2004 12:23:53 AM

Archived from groups: uk.comp.homebuilt,alt.comp.hardware,alt.comp.hardware.pc-homebuilt (More info?)

"w_tom" wrote in message
> Even the USB standard has special hardware and provisions so
> that USB devices can be 'hot popped'. Connecting and
> disconnecting devices from a buss requires special hardware so
> that hot popping causes neither system crashes nor hardware
> damage. System crashing alone is not the only symptom.

I read that and immidiately the words "Bill Gates" + "USB" + "press
conference" +" Blue screen of death" +" embarassed looks" spring to
mind.....

:-)


--
No66y©
Those who find they're touched by madness
Sit down next to me

Reply to address is a spam trap.
Use no66y [at] breathe [dot] com
Anonymous
a b B Homebuilt system
December 25, 2004 12:23:54 AM

Archived from groups: uk.comp.homebuilt,alt.comp.hardware,alt.comp.hardware.pc-homebuilt (More info?)

From the little bit I was able to piece together, the USB
hardware standard was properly developed (Intel, et al). But
the software standard was flawed. So flawed that the NT
Operating System group refused to put USB drivers into NT
4.0. This is why USB never really worked reliably until and
after Windows 98SE.

Appreciate how much more complex a hardware interface
becomes once you add 'hot popping' abilities and other simple
improvements. Based upon the text in that USB standard, the
USB serial bus alone is as complicated as the entire DOS
operating system. One would be amazed how complex that silly
little USB port really is. The ability to hot pop is but one
reason by USB is so complex.

"no66y©" wrote:
> "w_tom" wrote in message
>> Even the USB standard has special hardware and provisions so
>> that USB devices can be 'hot popped'. Connecting and
>> disconnecting devices from a buss requires special hardware so
>> that hot popping causes neither system crashes nor hardware
>> damage. System crashing alone is not the only symptom.
>
> I read that and immidiately the words "Bill Gates" + "USB" + "press
> conference" +" Blue screen of death" +" embarassed looks" spring to
> mind.....
>
> :-)
December 25, 2004 3:46:21 AM

Archived from groups: alt.comp.hardware.pc-homebuilt (More info?)

On Thu, 23 Dec 2004 17:55:10 GMT, Franklin <no_thanks@mail.com> wrote:

>I usually switch off my PC before I change a PCI card but a recent
>case I wanted to remove a modem card, then inspect the markings and
>then restore it in the PC.
>
>If I don't switch off the PC then what sort of damage might I cause?

Try it. Then let us know the damage.
Anonymous
a b B Homebuilt system
December 25, 2004 4:40:57 AM

Archived from groups: uk.comp.homebuilt,alt.comp.hardware,alt.comp.hardware.pc-homebuilt (More info?)

"Rene" <invalid@invalid.com> wrote:

....

>There is one reason why hardware interrupts were invented, and that
>is so that polling wouldn't be necessary anymore.

Can you please provide a citation for that.

Apparently the acronym IRQ means Interrupt ReQuest.

An IRQ is probably just a logic input that is either zero or one. The
integrated circuit would have to poll that pin/input from time to time.

But maybe you are talking about some other form of polling? It sounds
important (for trivia).
Anonymous
a b B Homebuilt system
December 25, 2004 4:50:44 AM

Archived from groups: uk.comp.homebuilt,alt.comp.hardware,alt.comp.hardware.pc-homebuilt (More info?)

mhaase-at-springmind.com <mhaase-at-springmind.com@> wrote:
>Ken <user@domain.invalid> wrote:

>> I don't want to kick a dead horse, but I must ask you a
>>question: Are you saying then that assuming no damage was done in
>>removing and re-installing the PCI modem with power on, that the
>>system would still think it had the same modem as before it was
>>removed? I have not pulled many such cards, but I seem to recall
>>that even disconnecting a HD from the IDE bus caused the drive to
>>be removed from the hardware it thought it had. Needless to say I
>>did not do this often enough to be certain of the outcome. I look
>>forward to your reply.

>Why don't you tell us the "end result" you're after here - maybe we
>can help you get it. It seems like you're trying to accomplish
>something (troubleshooting a modem problem?), and are going about
>it the wrong way.

You aren't replying to the original poster, and the person you are
replying to isn't really asking for help IMO.




>
>
>M
>
>
>
>Path: newssvr30.news.prodigy.com!newsdbm05.news.prodigy.com!
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>From: mhaase-at-springmind.com <mhaase-at-springmind.com@>
>Newsgroups:
uk.comp.homebuilt,alt.comp.hardware,alt.comp.hardware.pc-homebuilt
>Subject: Re: Changing PCI cards without switching off?
>Approved: I think so!
>Date: Fri, 24 Dec 2004 16:39:26 -0800
>Organization: My House
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>
Anonymous
a b B Homebuilt system
December 25, 2004 5:42:20 AM

Archived from groups: uk.comp.homebuilt,alt.comp.hardware,alt.comp.hardware.pc-homebuilt (More info?)

"John Doe" <jdoe@usenet.is.the.real.thing> wrote in message
news:Xns95C9C83B54C9Awisdomfolly@151.164.30.48...
> "Rene" <invalid@invalid.com> wrote:
>
> ...
>
> >There is one reason why hardware interrupts were invented, and that
> >is so that polling wouldn't be necessary anymore.
>
> Can you please provide a citation for that.
>
> Apparently the acronym IRQ means Interrupt ReQuest.
>
> An IRQ is probably just a logic input that is either zero or one. The
> integrated circuit would have to poll that pin/input from time to time.

Uhm, no... There is no polling. When the interrupt fires a circuit is
triggered.
Anonymous
a b B Homebuilt system
December 25, 2004 6:40:17 AM

Archived from groups: uk.comp.homebuilt,alt.comp.hardware,alt.comp.hardware.pc-homebuilt (More info?)

John Doe wrote, in response to my question on whether hot-plugging PCI
cards has been known to cause damage:

> I read that some have.

Thanks, that looks like the information I am seeking. Could you give
some details and references, please?

> If you want electrical/electronic explanations, maybe you should post
> to (sci.electronics...) groups.

I DON'T want any explanations, I'm seeking empirical, observational,
factual evidence that this problem, rather than just being a
possibility, actually does occur. the mechanism is very simple and quite
clear. If a card is plugged into a live system, the connections are made
in some sequence, not virtually simultaneously. If certain connections
are made before others, non-standard currents will flow (e.g., through
semiconductor junctions in signal circuits, instead of directly to
earth). If the magnitude and duration of these currents is such as to
generate more energy than can be dissipated, junctions will be
destroyed. If the junctions can, in fact, withstand the currents applied
for long enough, they will not be destroyed.

Best wishes,
--
Michael Salem
Anonymous
a b B Homebuilt system
December 25, 2004 7:12:41 AM

Archived from groups: uk.comp.homebuilt,alt.comp.hardware,alt.comp.hardware.pc-homebuilt (More info?)

w_tom wrote:

> Doing something is just fine only because it did not cause
> failures previously? What kind of logic is that?

I originally raised the question of whether hot-plugging standard PCI
cards has actually been known to cause damage, so had better point out
that I have always been careful to pointout that I don't advocate the
even if it doesn't actually appear to cause damage; and nobody posting
here has implied that hot-plugging is fine.

> Some
> darkening of the first O'ring was the only apparent effect
> when launching a space shuttle in sub freezing weather...

Funnily enough, I had thought of the exact same example in this context.
An O-ring which was not getting eroded at all was getting eroded to one-
third of its thickness, so the project managers said that there was a 3-
to-1 safety factor, rather than that something unexpected was happening,
See Richard Feynman's report. Similar in principle, though not in
consequences, to hot-plugging, getting away with it, and adopting it as
standard practice.

The second fatal shuttle disaster was due to exactly the same attitude:
bits of foam come off and bash into the structure, though they're not
supposed to; we've got away with every time; so let's keep doing it.


I have simply asked whether damage has been observed without giving any
reasons. My reasons for asking the question are in fact:

a. Simple curiosity: is this actually seen to happen in practice?

b. If hot-plugging is done accidentally, what are likely to be the
consequences?

c. If there are legitimate reasons for hot-plugging: how dangerous
actually is it to motherboard and card?

A legitimate reason: an Adaptec 2940U2W PCI SCSI card has its BIOS
flashed unsuccessfully. The card is not recognised by the operating
system, and hence can't be re-flashed (in some case the machine will not
boot); the BIOS is soldered in; and the manufacturer cannot repair. The
card (fairly expensive to replace) is junk.

Possible attempt to repair: boot the machine with a good card, or with
no card; hot-unplug good card; hot-plug bad card; try running flash
procedure.

This issue has been discussed on Usenet, and hot-plugging has been done
and not caused damage. I have Googled for, but not found, instances of
damage.


> [detailed comments on why not to hot-swap]

If these comments are for my benefit rather than a contribution to the
general discussion (as I raised the question) don't feel you need to
explain: I have designed and repaired circuitry and know and play by the
rules of the game, even if I ask questions about them.

As I keep on saying: I don't disagree with you in any way, I would just
be interested to hear about any actual observed consequences (or non-
consequences) of hot-plugging PCI. Even if it is usually harmless, there
are very few reasons to hot-plug in a machine which doesn't need to run
with zero downtime -- it would at best save a bit of rebooting time.

Best wishes,
--
Michael Salem
Anonymous
a b B Homebuilt system
December 25, 2004 7:16:45 AM

Archived from groups: uk.comp.homebuilt,alt.comp.hardware,alt.comp.hardware.pc-homebuilt (More info?)

John Doe wrote:

> That makes at least the third time you have said that in this
> thread. And that disagrees with what I have read.

Many thanks, that is precisely the information I seek, and the answer to
my question. What did you read, and where, please?
Anonymous
a b B Homebuilt system
December 25, 2004 9:45:28 AM

Archived from groups: uk.comp.homebuilt,alt.comp.hardware,alt.comp.hardware.pc-homebuilt (More info?)

"Noozer" <dontspam@me.here> wrote:
>"John Doe" <jdoe@usenet.is.the.real.thing> wrote in message
>> "Rene" <invalid@invalid.com> wrote:
>>
>> ...
>>
>> >There is one reason why hardware interrupts were invented, and
>> >that is so that polling wouldn't be necessary anymore.
>>
>> Can you please provide a citation for that.
>>
>> Apparently the acronym IRQ means Interrupt ReQuest.
>>
>> An IRQ is probably just a logic input that is either zero or one.
>> The integrated circuit would have to poll that pin/input from
>> time to time.
>
>Uhm, no... There is no polling. When the interrupt fires a circuit
>is triggered.

What is "the interrupt fires" supposed to mean?





>
>
>
>
>
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Anonymous
a b B Homebuilt system
December 25, 2004 9:53:33 AM

Archived from groups: uk.comp.homebuilt,alt.comp.hardware,alt.comp.hardware.pc-homebuilt (More info?)

Troll.

Michael Salem <a$-b$1@ms3.org.uk> wrote:

>Path: newssvr11.news.prodigy.com!newscon03.news.prodigy.com!newsmst01a.news.prodigy.com!prodigy.com!fu-berlin.de!uni-berlin.de!individual.net!not-for-mail
>From: Michael Salem <a$-b$1@ms3.org.uk>
>Newsgroups: uk.comp.homebuilt,alt.comp.hardware,alt.comp.hardware.pc-homebuilt
>Subject: Re: Changing PCI cards without switching off?
>Date: Sat, 25 Dec 2004 04:16:45 -0000
>Lines: 9
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>
>John Doe wrote:
>
>> That makes at least the third time you have said that in this
>> thread. And that disagrees with what I have read.
>
>Many thanks, that is precisely the information I seek, and the answer to
>my question. What did you read, and where, please?
>
>
>
Anonymous
a b B Homebuilt system
December 25, 2004 12:23:51 PM

Archived from groups: uk.comp.homebuilt,alt.comp.hardware,alt.comp.hardware.pc-homebuilt (More info?)

"John Doe" <jdoe@usenet.is.the.real.thing> wrote in message
news:Xns95C9C83B54C9Awisdomfolly@151.164.30.48...
> "Rene" <invalid@invalid.com> wrote:
> >There is one reason why hardware interrupts were invented, and that
> >is so that polling wouldn't be necessary anymore.
>
> Can you please provide a citation for that.
>
> Apparently the acronym IRQ means Interrupt ReQuest.
>
> An IRQ is probably just a logic input that is either zero or one. The
> integrated circuit would have to poll that pin/input from time to time.

In effect, yes, interrupt lines are polled in hardware. Often, pending
interrupts are acted upon at the start of the next instruction executed by
the processor.

> But maybe you are talking about some other form of polling? It sounds
> important (for trivia).

Rene refers to polling in software, where the processor periodically
executes instructions to read a hardware register which indicates when the
hardware needs attention.

Alex
Anonymous
a b B Homebuilt system
December 25, 2004 2:15:03 PM

Archived from groups: uk.comp.homebuilt,alt.comp.hardware,alt.comp.hardware.pc-homebuilt (More info?)

On Fri, 24 Dec 2004 17:50:44 -0800, John Doe
<jdoe@usenet.is.the.real.thing> wrote:

>mhaase-at-springmind.com <mhaase-at-springmind.com@> wrote:
>>Ken <user@domain.invalid> wrote:
>
>>> I don't want to kick a dead horse, but I must ask you a
>>>question: Are you saying then that assuming no damage was done in
>>>removing and re-installing the PCI modem with power on, that the
>>>system would still think it had the same modem as before it was
>>>removed? I have not pulled many such cards, but I seem to recall
>>>that even disconnecting a HD from the IDE bus caused the drive to
>>>be removed from the hardware it thought it had. Needless to say I
>>>did not do this often enough to be certain of the outcome. I look
>>>forward to your reply.
>
>>Why don't you tell us the "end result" you're after here - maybe we
>>can help you get it. It seems like you're trying to accomplish
>>something (troubleshooting a modem problem?), and are going about
>>it the wrong way.
>
>You aren't replying to the original poster, and the person you are
>replying to isn't really asking for help IMO.


You're right, of course. My mistake. Thanx! Happy Holidays!





>>
>>Path: newssvr30.news.prodigy.com!newsdbm05.news.prodigy.com!
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>>From: mhaase-at-springmind.com <mhaase-at-springmind.com@>
>>Newsgroups:
>uk.comp.homebuilt,alt.comp.hardware,alt.comp.hardware.pc-homebuilt
>>Subject: Re: Changing PCI cards without switching off?
>>Approved: I think so!
>>Date: Fri, 24 Dec 2004 16:39:26 -0800
>>Organization: My House
>>Message-ID: <ccdps0hml4l32dm5n4nd8tae3upce4qpa1@4ax.com>
>>Reply-To: mhaase-at-springmind.com (Mark Haase)
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>news.ops.worldnet.att.net>
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>>
December 25, 2004 3:54:09 PM

Archived from groups: uk.comp.homebuilt,alt.comp.hardware,alt.comp.hardware.pc-homebuilt (More info?)

I must say that I often don't manage to get a PCI card in anything like
straight first time. Result must be that half of the connectors on the card
are bridging across two connectors on the socket. Which half depends on
whether the front or back of the card goes in further.

I don't see how you design a card/bus to cope with that sort of
ham-fistedness when the system is live. Obviously it would help if it was
all very high impedance, but I thought that at least the power connectors
provide a few watts, no?

At the least, to hot-swap PCI cards, you would need some sort of mechanical
system to ensure they go in more or less straight?

Geoff
December 25, 2004 4:24:16 PM

Archived from groups: uk.comp.homebuilt,alt.comp.hardware,alt.comp.hardware.pc-homebuilt (More info?)

mhaase-at-springmind.com wrote:
> On Fri, 24 Dec 2004 13:02:43 -0800, Ken <user@domain.invalid> wrote:
>
>
>
>> I don't want to kick a dead horse, but I must ask you a question: Are
>>you saying then that assuming no damage was done in removing and
>>re-installing the PCI modem with power on, that the system would still
>>think it had the same modem as before it was removed? I have not pulled
>>many such cards, but I seem to recall that even disconnecting a HD from
>>the IDE bus caused the drive to be removed from the hardware it thought
>>it had. Needless to say I did not do this often enough to be certain of
>>the outcome. I look forward to your reply.
>
>
>
> Ken -
>
> Why don't you tell us the "end result" you're after here - maybe we
> can help you get it. It seems like you're trying to accomplish
> something (troubleshooting a modem problem?), and are going about it
> the wrong way.
>
>
> M
>
>
What I am after is an explanation of how certain he is of his
statement. I AM NOT SURE OF MINE, but my experiences led me to believe
the computer would drop the device pulled from the socket if done so
with power on, and not work if inserted again without rebooting. If he
IS SURE OF HIS statement, then I trust he is correct. My question is
one of curiosity and NOT criticism. THAT is what I am trying to
accomplish. If YOU have the ability to answer the question I posed, by
all means answer it. So to answer your question, I am after KNOWLEDGE.

I have worked on hundreds of computers, and I AM STILL LEARNING. I DO
NOT HAVE ALL THE ANSWERS, AND NEVER WILL. One of the great things about
the news groups is that you can learn from the experiences of others if
you are willing to listen and ask questions. That is, unless some other
poster who has nothing to add but criticism turns off those willing to
add their experiences and comments. Lighten up!!
!