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Re: Shortest period to switch off electronic equipent for before switching on
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Rheilly Phoull
Apr 8, 2017, 6:04:18 AM4/8/17
to
On 8/04/2017 5:33 PM, pamela wrote:
> As a rule of thumb, what's the shortest period to switch off
> electronic equipment for a reset before switching on?
>
> I mean equipment like televisions, PVR, satellite or cable boxes,
> PCs, cordless phones, clock radios, etc.
>
> My teenage relative reset our Humax PVR by switching it off and
> almost INSTANTLY switched it on again. I told him to be patient
> but how long should he wait for in general?
>
> Twenty years ago 5 seconds would have been enough but nowadays some
> electronic devices (like my Samsung tv) shows its power LED for 10 or
> 20 seconds after the mains is disconnected. Also hard drives in
> Playstations and PVRs will spin on. Telling impatient kids to go and
> make a cup of coffee isn't going to work.
>
You might want to regulate your relatives when they are in YOUR HOME.
As you say some things need a few seconds to reset.
> As a rule of thumb, what's the shortest period to switch off
> electronic equipment for a reset before switching on?
>
> I mean equipment like televisions, PVR, satellite or cable boxes,
> PCs, cordless phones, clock radios, etc.
>
> My teenage relative reset our Humax PVR by switching it off and
> almost INSTANTLY switched it on again. I told him to be patient
> but how long should he wait for in general?
>
> Twenty years ago 5 seconds would have been enough but nowadays some
> electronic devices (like my Samsung tv) shows its power LED for 10 or
> 20 seconds after the mains is disconnected. Also hard drives in
> Playstations and PVRs will spin on. Telling impatient kids to go and
> make a cup of coffee isn't going to work.
>
You might want to regulate your relatives when they are in YOUR HOME.
As you say some things need a few seconds to reset.
Davey
Apr 8, 2017, 6:16:47 AM4/8/17
to
On Sat, 08 Apr 2017 10:33:44 +0100
pamela <inv...@nospam.com> wrote:
> As a rule of thumb, what's the shortest period to switch off
> electronic equipment for a reset before switching on?
>
> I mean equipment like televisions, PVR, satellite or cable boxes,
> PCs, cordless phones, clock radios, etc.
>
> My teenage relative reset our Humax PVR by switching it off and
> almost INSTANTLY switched it on again. I told him to be patient
> but how long should he wait for in general?
>
> Twenty years ago 5 seconds would have been enough but nowadays some
> electronic devices (like my Samsung tv) shows its power LED for 10 or
> 20 seconds after the mains is disconnected. Also hard drives in
> Playstations and PVRs will spin on. Telling impatient kids to go and
> make a cup of coffee isn't going to work.
My Humax HDR Fox T2 says to wait until you hear the HDD wind down
pamela <inv...@nospam.com> wrote:
> As a rule of thumb, what's the shortest period to switch off
> electronic equipment for a reset before switching on?
>
> I mean equipment like televisions, PVR, satellite or cable boxes,
> PCs, cordless phones, clock radios, etc.
>
> My teenage relative reset our Humax PVR by switching it off and
> almost INSTANTLY switched it on again. I told him to be patient
> but how long should he wait for in general?
>
> Twenty years ago 5 seconds would have been enough but nowadays some
> electronic devices (like my Samsung tv) shows its power LED for 10 or
> 20 seconds after the mains is disconnected. Also hard drives in
> Playstations and PVRs will spin on. Telling impatient kids to go and
> make a cup of coffee isn't going to work.
before turning it on again. Otherwise, I generally try to wait for 30
secs. as a rule of thumb, although I'm not always that patient. Not
that I have to reset stuff much anyway.
If they're in your home, then visitors work to your rules!
--
Davey.
David Woolley
Apr 8, 2017, 7:03:16 AM4/8/17
to
On 08/04/17 10:33, pamela wrote:
> As a rule of thumb, what's the shortest period to switch off
> electronic equipment for a reset before switching on?
There are two issues here:
> As a rule of thumb, what's the shortest period to switch off
> electronic equipment for a reset before switching on?
1) allowing long enough for a reset to be reliable;
2) ensuring it is safe to power down before doing so.
On the second point, PVRs, in particular, do not seem to be designed to
be really safe to power down at any time, as there is no way of putting
them into a soft power down state. You have to make sure that there are
no recordings scheduled and put them into standby. On my Humax, you
then need to wait until the red light dims
Otherwise, you will be relying on the consumer user defences built into
the disk drives ensure that the current write completes and the heads
park, and also to recover any logical damage to the filesystem. Even
PC's are quite good at this these days, and should never be given a hard
power down until a soft power down has completed, unless they have
completely locked up and there is no reset button.
On the first point, it depends on the design of the electronics as to
how long it takes for all capacitors to discharge sufficiently to put
them into a clearly off state. Remember that some devices will detect a
warm start by reading RAM, and maximum retention times, without
refreshes, are not characterised for dynamic RAM, only minimum ones.
Also the time constants associated with some faults that require resets
can be hours.
Where a hard power cycle is needed, I would probably go for about 30
seconds for the first attempt, and then overnight, if the first attempt
doesn't succeed.
Of course, you should not need to reset the device this way at all,
unless there is a fault, so it is probably something that you should not
allow visitors to do at all.
Davey
Apr 8, 2017, 7:11:41 AM4/8/17
to
On Sat, 8 Apr 2017 12:03:14 +0100
David Woolley <da...@ex.djwhome.demon.invalid> wrote:
> Of course, you should not need to reset the device this way at all,
> unless there is a fault,
A few days ago, for the first time that I have ever seen, my Humax
David Woolley <da...@ex.djwhome.demon.invalid> wrote:
> Of course, you should not need to reset the device this way at all,
> unless there is a fault,
refused to respond when I tried to turn it on. Neither the remote
control nor the big button would make it work. I turned it off with the
switch on the back panel, waited some time, probably less than 30
seconds, and then turned it on again. Since then, it's worked fine. The
log showed nothing of any use, so I have no idea what the problem was.
The unit is now about 4 years old, and was a refurbished unit when I got
it, so I have had my money's worth if it failed at any time.
--
Davey.
MJC
Apr 8, 2017, 12:15:25 PM4/8/17
to
In article <ocafrr$ehp$1...@dont-email.me>, da...@ex.djwhome.demon.invalid
says...
hand, it sometimes gets stuck and has to be powered down to reset it.
And I give it several seconds, but not as many as 30!
Mike.
says...
>
> On the second point, PVRs, in particular, do not seem to be designed
to
> be really safe to power down at any time, as there is no way of putting
> them into a soft power down state. You have to make sure that there are
> no recordings scheduled and put them into standby. On my Humax, you
> then need to wait until the red light dims
My Humax (old 9200T) will record even when in standby. On the other
> On the second point, PVRs, in particular, do not seem to be designed
to
> be really safe to power down at any time, as there is no way of putting
> them into a soft power down state. You have to make sure that there are
> no recordings scheduled and put them into standby. On my Humax, you
> then need to wait until the red light dims
hand, it sometimes gets stuck and has to be powered down to reset it.
And I give it several seconds, but not as many as 30!
Mike.
Benderthe.evilrobot
Apr 8, 2017, 3:16:40 PM4/8/17
to
"pamela" <inv...@nospam.com> wrote in message
news:XnsA7516B7...@81.171.92.183...
> As a rule of thumb, what's the shortest period to switch off
> electronic equipment for a reset before switching on?
>
> electronic equipment for a reset before switching on?
>
> I mean equipment like televisions, PVR, satellite or cable boxes,
> PCs, cordless phones, clock radios, etc.
>
> My teenage relative reset our Humax PVR by switching it off and
> almost INSTANTLY switched it on again. I told him to be patient
> but how long should he wait for in general?
>
> Twenty years ago 5 seconds would have been enough but nowadays some
> electronic devices (like my Samsung tv) shows its power LED for 10 or
> 20 seconds after the mains is disconnected. Also hard drives in
> Playstations and PVRs will spin on. Telling impatient kids to go and
> make a cup of coffee isn't going to work.
You can't just lump everything into the same bracket - a lot of people just
> PCs, cordless phones, clock radios, etc.
>
> My teenage relative reset our Humax PVR by switching it off and
> almost INSTANTLY switched it on again. I told him to be patient
> but how long should he wait for in general?
>
> Twenty years ago 5 seconds would have been enough but nowadays some
> electronic devices (like my Samsung tv) shows its power LED for 10 or
> 20 seconds after the mains is disconnected. Also hard drives in
> Playstations and PVRs will spin on. Telling impatient kids to go and
> make a cup of coffee isn't going to work.
turn the TV off "cold turkey", its a lot better than leaving it unattended
on standby.
Anything with a hard drive can trash a file if you power down in the middle
of a write operation.
Some designs of SMPSU can go bang if you switch back on before the reservoir
caps discharge and those with inrush surge limiting have a thermal recovery
time for no protection - but it just stresses the components a little more
than usual. Most user manuals seem more or less unanimous for about 30s.
---
This email has been checked for viruses by AVG.
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ohg...@gmail.com
Apr 8, 2017, 8:22:56 PM4/8/17
to
olds...@tubes.com
Apr 8, 2017, 8:34:58 PM4/8/17
to
things is always using power when it's turned off. A few weeks ago,
while this receiver was OFF, I removed the speaker wires to test another
amp. I then unplugged the receiver. Last week I put the speaker wires
back on that receiver (it was still unplugged). There was a loud pop on
each channel when I put the wires on it. (That was around 16 days
later). Those caps must hold power for a real long time..... (There is
no battery of any sort in this thing).
Another thing, I have an external 56K modem that I use to connect (on
dialup). Once and awhile if I shut off connection, later on, I have
trouble connecting to the internet. I found that if I just shut the
power off to that modem, it seems to reset it and thn it connects fine.
BUT. I have to shut it off for about 30 seconds. Just ON-OFF dont work.
I assume the caps need to discharge to do the reset....
k...@notreal.com
Apr 8, 2017, 10:05:30 PM4/8/17
to
>"pamela" <inv...@nospam.com> wrote in message
>news:XnsA7516B7...@81.171.92.183...
>> As a rule of thumb, what's the shortest period to switch off
>> electronic equipment for a reset before switching on?
>>
>> I mean equipment like televisions, PVR, satellite or cable boxes,
>> PCs, cordless phones, clock radios, etc.
>>
>> My teenage relative reset our Humax PVR by switching it off and
>> almost INSTANTLY switched it on again. I told him to be patient
>> but how long should he wait for in general?
>>
>> Twenty years ago 5 seconds would have been enough but nowadays some
>> electronic devices (like my Samsung tv) shows its power LED for 10 or
>> 20 seconds after the mains is disconnected. Also hard drives in
>> Playstations and PVRs will spin on. Telling impatient kids to go and
>> make a cup of coffee isn't going to work.
>
>You can't just lump everything into the same bracket - a lot of people just
>turn the TV off "cold turkey", its a lot better than leaving it unattended
>on standby.
There is absolutly nothing wrong with "standby".
>news:XnsA7516B7...@81.171.92.183...
>> As a rule of thumb, what's the shortest period to switch off
>> electronic equipment for a reset before switching on?
>>
>> I mean equipment like televisions, PVR, satellite or cable boxes,
>> PCs, cordless phones, clock radios, etc.
>>
>> My teenage relative reset our Humax PVR by switching it off and
>> almost INSTANTLY switched it on again. I told him to be patient
>> but how long should he wait for in general?
>>
>> Twenty years ago 5 seconds would have been enough but nowadays some
>> electronic devices (like my Samsung tv) shows its power LED for 10 or
>> 20 seconds after the mains is disconnected. Also hard drives in
>> Playstations and PVRs will spin on. Telling impatient kids to go and
>> make a cup of coffee isn't going to work.
>
>You can't just lump everything into the same bracket - a lot of people just
>turn the TV off "cold turkey", its a lot better than leaving it unattended
>on standby.
>
>Anything with a hard drive can trash a file if you power down in the middle
>of a write operation.
Nonsense. There are many ways to design a device that will survive a
>Anything with a hard drive can trash a file if you power down in the middle
>of a write operation.
power failure during disk write. A bit of reserve power is probably
the best solution but a JFS works, too.
>
>Some designs of SMPSU can go bang if you switch back on before the reservoir
>caps discharge and those with inrush surge limiting have a thermal recovery
>time for no protection - but it just stresses the components a little more
>than usual. Most user manuals seem more or less unanimous for about 30s.
Only if it's designed by a moron.
>Some designs of SMPSU can go bang if you switch back on before the reservoir
>caps discharge and those with inrush surge limiting have a thermal recovery
>time for no protection - but it just stresses the components a little more
>than usual. Most user manuals seem more or less unanimous for about 30s.
alan_m
Apr 9, 2017, 4:27:44 AM4/9/17
to
On 08/04/2017 10:33, pamela wrote:
> As a rule of thumb, what's the shortest period to switch off
> electronic equipment for a reset before switching on?
>
> I mean equipment like televisions, PVR, satellite or cable boxes,
> PCs, cordless phones, clock radios, etc.
>
> My teenage relative reset our Humax PVR by switching it off and
> almost INSTANTLY switched it on again. I told him to be patient
> but how long should he wait for in general?
>
> Twenty years ago 5 seconds would have been enough but nowadays some
> electronic devices (like my Samsung tv) shows its power LED for 10 or
> 20 seconds after the mains is disconnected. Also hard drives in
> Playstations and PVRs will spin on. Telling impatient kids to go and
> make a cup of coffee isn't going to work.
>
Twenty years ago 5 seconds may have caused a problem due to the
> As a rule of thumb, what's the shortest period to switch off
> electronic equipment for a reset before switching on?
>
> I mean equipment like televisions, PVR, satellite or cable boxes,
> PCs, cordless phones, clock radios, etc.
>
> My teenage relative reset our Humax PVR by switching it off and
> almost INSTANTLY switched it on again. I told him to be patient
> but how long should he wait for in general?
>
> Twenty years ago 5 seconds would have been enough but nowadays some
> electronic devices (like my Samsung tv) shows its power LED for 10 or
> 20 seconds after the mains is disconnected. Also hard drives in
> Playstations and PVRs will spin on. Telling impatient kids to go and
> make a cup of coffee isn't going to work.
>
possibility of surges due to mains input filters.
Often if the switch off is to cold boot crashed software then the
internal PSU voltages have to decay. My rule of thumb is 30 seconds
after any front panel LED has gone out.
--
mailto: news {at} admac {dot] myzen {dot} co {dot} uk
David Woolley
Apr 9, 2017, 4:35:14 AM4/9/17
to
On 08/04/17 17:15, MJC wrote:
> My Humax (old 9200T) will record even when in standby
That's why I said you must make sure there are no recordings scheduled!
> My Humax (old 9200T) will record even when in standby
Brian Gaff
Apr 9, 2017, 4:55:35 AM4/9/17
to
In my view all devices should have a little pin hole switch that does this
for you.
It really depends on the device I think. Things like my Smart talk freeview
box almost instantaneous resets are OK if done via the little plug from the
psu on the back, but if you do it from the mains it needs a little longer as
I suspect the wall wart has some capacitors in it.
Phones are awhole other ball of nuts.
Some seem to remember crashes indefinitely. there is one which is not out
of production where the software crashes and stops the voice from working at
all, even if you take the battery out.
Sadly as nobody has the gear to reblow the software any more its a brick.
Brian
--
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This newsgroup posting comes to you directly from...
The Sofa of Brian Gaff...
bri...@blueyonder.co.uk
Blind user, so no pictures please!
for you.
It really depends on the device I think. Things like my Smart talk freeview
box almost instantaneous resets are OK if done via the little plug from the
psu on the back, but if you do it from the mains it needs a little longer as
I suspect the wall wart has some capacitors in it.
Phones are awhole other ball of nuts.
Some seem to remember crashes indefinitely. there is one which is not out
of production where the software crashes and stops the voice from working at
all, even if you take the battery out.
Sadly as nobody has the gear to reblow the software any more its a brick.
Brian
--
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This newsgroup posting comes to you directly from...
The Sofa of Brian Gaff...
bri...@blueyonder.co.uk
Blind user, so no pictures please!
Brian Gaff
Apr 9, 2017, 5:01:35 AM4/9/17
to
Not many people understand computer shut down via the button either If
software has locked up or is doing odd things, then a short tap on the power
button, ie NOT the reset is normally the way to get a good shutdown. If that
fails, then hold in the power button, NOT the reset button as this normally
protects the hard drive from corruption. all these folks wo either press
reset or worse, just pull the plug out deserve the reinstall they
evenntually end up having to do.
Brian
Of course if there is a power cut this can happen anyway, and I've often
thought of putting in an uninteruptable supply to allow proper shut down.
they are not that expensive these days, and laptops of course have one built
in.
news:ocadad$j1m$4...@n102.xanadu-bbs.net...
software has locked up or is doing odd things, then a short tap on the power
button, ie NOT the reset is normally the way to get a good shutdown. If that
fails, then hold in the power button, NOT the reset button as this normally
protects the hard drive from corruption. all these folks wo either press
reset or worse, just pull the plug out deserve the reinstall they
evenntually end up having to do.
Brian
Of course if there is a power cut this can happen anyway, and I've often
thought of putting in an uninteruptable supply to allow proper shut down.
they are not that expensive these days, and laptops of course have one built
in.
Brian
--
----- -
This newsgroup posting comes to you directly from...
The Sofa of Brian Gaff...
bri...@blueyonder.co.uk
Blind user, so no pictures please!
"Davey" <da...@example.invalid> wrote in message
--
----- -
This newsgroup posting comes to you directly from...
The Sofa of Brian Gaff...
bri...@blueyonder.co.uk
Blind user, so no pictures please!
news:ocadad$j1m$4...@n102.xanadu-bbs.net...
NY
Apr 9, 2017, 7:20:52 AM4/9/17
to
<k...@notreal.com> wrote in message
news:sg5jeclipaol2ejgd...@4ax.com...
trashed if the power goes off during a write, though the time during which
the files is in an inconsistent state between data sectors and sector map
may be less with solid state than a mechanical rotating disk.
> Nonsense. There are many ways to design a device that will survive a
> power failure during disk write. A bit of reserve power is probably
> the best solution but a JFS works, too.
It depends what filesystem they use. NTFS is pretty robust but it requires a
licence to be paid to the inventors which is why a lot of PVRs use/read only
FAT/FAT32. If they are Linux-based they will be able to use filesystems
which are more robust (I'm not very clued up on Linux).
But I'd say that a design which trashes the file that is being written to or
the whole filesystem when the power goes off (eg due to a power-cut, which
is not totally unexpected) is a bad design: you need some form of resilience
in terms of battery-backed supply until the file write is complete and
consistent.
I use my Windows 7 PC as a PVR (either Windows Media Centre or NextPVR) and
I've occasionally had power cuts during recording. I've never yet lost the
recording that was being made or the filesystem of the recording HDD (NTFS).
OK, Windows may do a chkdsk repair after the PC reboots, but it seems to
sort itself out.
A UPS would be useful for graceful shutting down during power cuts, but it
might be more trouble that it's worth. At present my BIOS is set to reboot
the PC automatically after the power is restored. If the UPS keeps the power
up and initiates a graceful shutdown, the PC may not boot back up once the
power comes back.
My wife bought a 3kVA UPS with her big Dell PC about 10 years ago. We didn't
get round to setting up the UPS for a couple of years. By the time we did
(and after the warranty had expired, inevitably) we found that it had
virtually no battery capacity: the battery monitoring software (monitored by
USB connection) showed the battery accepting charge and gradually charging
up and eventually showing as fully charged, but as soon as the mains was
removed, the battery discharged within about 10 seconds with a nominal 40 W
lightbulb as the load. Utterly useless, and it wasn't even worth buying a
replacement battery for it because the fault may have been in the charging
circuit rather than the battery itself. APC didn't want to know when we
asked what a repair might cost, so it went in the skip - a waste of money as
it was never even used.
Moral of the story: always try any new hardware during the warranty period!
news:sg5jeclipaol2ejgd...@4ax.com...
>>You can't just lump everything into the same bracket - a lot of people
>>just
>>turn the TV off "cold turkey", its a lot better than leaving it unattended
>>on standby.
>
> There is absolutly nothing wrong with "standby".
>>
>>Anything with a hard drive can trash a file if you power down in the
>>middle
>>of a write operation.
I suppose anything with disk-like storage (including flash drives) can be
>>just
>>turn the TV off "cold turkey", its a lot better than leaving it unattended
>>on standby.
>
> There is absolutly nothing wrong with "standby".
>>
>>Anything with a hard drive can trash a file if you power down in the
>>middle
>>of a write operation.
trashed if the power goes off during a write, though the time during which
the files is in an inconsistent state between data sectors and sector map
may be less with solid state than a mechanical rotating disk.
> Nonsense. There are many ways to design a device that will survive a
> power failure during disk write. A bit of reserve power is probably
> the best solution but a JFS works, too.
licence to be paid to the inventors which is why a lot of PVRs use/read only
FAT/FAT32. If they are Linux-based they will be able to use filesystems
which are more robust (I'm not very clued up on Linux).
But I'd say that a design which trashes the file that is being written to or
the whole filesystem when the power goes off (eg due to a power-cut, which
is not totally unexpected) is a bad design: you need some form of resilience
in terms of battery-backed supply until the file write is complete and
consistent.
I use my Windows 7 PC as a PVR (either Windows Media Centre or NextPVR) and
I've occasionally had power cuts during recording. I've never yet lost the
recording that was being made or the filesystem of the recording HDD (NTFS).
OK, Windows may do a chkdsk repair after the PC reboots, but it seems to
sort itself out.
A UPS would be useful for graceful shutting down during power cuts, but it
might be more trouble that it's worth. At present my BIOS is set to reboot
the PC automatically after the power is restored. If the UPS keeps the power
up and initiates a graceful shutdown, the PC may not boot back up once the
power comes back.
My wife bought a 3kVA UPS with her big Dell PC about 10 years ago. We didn't
get round to setting up the UPS for a couple of years. By the time we did
(and after the warranty had expired, inevitably) we found that it had
virtually no battery capacity: the battery monitoring software (monitored by
USB connection) showed the battery accepting charge and gradually charging
up and eventually showing as fully charged, but as soon as the mains was
removed, the battery discharged within about 10 seconds with a nominal 40 W
lightbulb as the load. Utterly useless, and it wasn't even worth buying a
replacement battery for it because the fault may have been in the charging
circuit rather than the battery itself. APC didn't want to know when we
asked what a repair might cost, so it went in the skip - a waste of money as
it was never even used.
Moral of the story: always try any new hardware during the warranty period!
Look165
Apr 9, 2017, 8:17:58 AM4/9/17
to
Generally, the off/on if too short implies caps (generally somme 100µF)
not to discharge totally and if on again during this state, the result
is unpredictable.
Thje more the device uses power, the less this time is needed.
Today, it seems that 10-15 s are enough.
For a modem (ADSL or cable) it's OK.
For a LCD or plasma TV too.
To be secure, count on 20s.
pamela a écrit :
not to discharge totally and if on again during this state, the result
is unpredictable.
Thje more the device uses power, the less this time is needed.
Today, it seems that 10-15 s are enough.
For a modem (ADSL or cable) it's OK.
For a LCD or plasma TV too.
To be secure, count on 20s.
pamela a écrit :
k...@notreal.com
Apr 9, 2017, 8:35:15 AM4/9/17
to
On Sun, 9 Apr 2017 12:21:16 +0100, "NY" <m...@privacy.net> wrote:
><k...@notreal.com> wrote in message
>news:sg5jeclipaol2ejgd...@4ax.com...
>>>You can't just lump everything into the same bracket - a lot of people
>>>just
>>>turn the TV off "cold turkey", its a lot better than leaving it unattended
>>>on standby.
>>
>> There is absolutly nothing wrong with "standby".
>>>
>>>Anything with a hard drive can trash a file if you power down in the
>>>middle
>>>of a write operation.
>
>I suppose anything with disk-like storage (including flash drives) can be
>trashed if the power goes off during a write, though the time during which
>the files is in an inconsistent state between data sectors and sector map
>may be less with solid state than a mechanical rotating disk.
>
>> Nonsense. There are many ways to design a device that will survive a
>> power failure during disk write. A bit of reserve power is probably
>> the best solution but a JFS works, too.
>
>It depends what filesystem they use. NTFS is pretty robust but it requires a
>licence to be paid to the inventors which is why a lot of PVRs use/read only
>FAT/FAT32. If they are Linux-based they will be able to use filesystems
>which are more robust (I'm not very clued up on Linux).
That's an economics decision. There is nothing cast in jello that
><k...@notreal.com> wrote in message
>news:sg5jeclipaol2ejgd...@4ax.com...
>>>You can't just lump everything into the same bracket - a lot of people
>>>just
>>>turn the TV off "cold turkey", its a lot better than leaving it unattended
>>>on standby.
>>
>> There is absolutly nothing wrong with "standby".
>>>
>>>Anything with a hard drive can trash a file if you power down in the
>>>middle
>>>of a write operation.
>
>I suppose anything with disk-like storage (including flash drives) can be
>trashed if the power goes off during a write, though the time during which
>the files is in an inconsistent state between data sectors and sector map
>may be less with solid state than a mechanical rotating disk.
>
>> Nonsense. There are many ways to design a device that will survive a
>> power failure during disk write. A bit of reserve power is probably
>> the best solution but a JFS works, too.
>
>It depends what filesystem they use. NTFS is pretty robust but it requires a
>licence to be paid to the inventors which is why a lot of PVRs use/read only
>FAT/FAT32. If they are Linux-based they will be able to use filesystems
>which are more robust (I'm not very clued up on Linux).
says they have to cheap out, or even use an existing FS. JFS
techniques are well known. Even if they do want to use a vulnerable
FS, a proper power system design can guarantee a safe shut down.
>
>But I'd say that a design which trashes the file that is being written to or
>the whole filesystem when the power goes off (eg due to a power-cut, which
>is not totally unexpected) is a bad design: you need some form of resilience
>in terms of battery-backed supply until the file write is complete and
>consistent.
Exactly so. This is common with flash-based systems. The power
>But I'd say that a design which trashes the file that is being written to or
>the whole filesystem when the power goes off (eg due to a power-cut, which
>is not totally unexpected) is a bad design: you need some form of resilience
>in terms of battery-backed supply until the file write is complete and
>consistent.
system has to guarantee at least the current block has been written.
>I use my Windows 7 PC as a PVR (either Windows Media Centre or NextPVR) and
>I've occasionally had power cuts during recording. I've never yet lost the
>recording that was being made or the filesystem of the recording HDD (NTFS).
>OK, Windows may do a chkdsk repair after the PC reboots, but it seems to
>sort itself out.
>A UPS would be useful for graceful shutting down during power cuts, but it
>might be more trouble that it's worth. At present my BIOS is set to reboot
>the PC automatically after the power is restored. If the UPS keeps the power
>up and initiates a graceful shutdown, the PC may not boot back up once the
>power comes back.
>
>My wife bought a 3kVA UPS with her big Dell PC about 10 years ago. We didn't
>get round to setting up the UPS for a couple of years. By the time we did
>(and after the warranty had expired, inevitably) we found that it had
>virtually no battery capacity: the battery monitoring software (monitored by
>USB connection) showed the battery accepting charge and gradually charging
>up and eventually showing as fully charged, but as soon as the mains was
>removed, the battery discharged within about 10 seconds with a nominal 40 W
>lightbulb as the load. Utterly useless, and it wasn't even worth buying a
>replacement battery for it because the fault may have been in the charging
>circuit rather than the battery itself. APC didn't want to know when we
>asked what a repair might cost, so it went in the skip - a waste of money as
>it was never even used.
emergency generators once a month. I have no idea why they had such
in the building I was in (just offices and a few labs at that time)
but they were there, so the were tested.
It's a really good idea to test your system backups from time to time,
too. You may find the restore doesn't work. :-(
>
>Moral of the story: always try any new hardware during the warranty period!
Anything that's important has to be tested.
>Moral of the story: always try any new hardware during the warranty period!
David Woolley
Apr 9, 2017, 9:22:43 AM4/9/17
to
On 09/04/17 10:01, Brian Gaff wrote:
> If that
> fails, then hold in the power button, NOT the reset button as this normally
> protects the hard drive from corruption.
As I understand it, a long press is handled by the hardware and forces a
> If that
> fails, then hold in the power button, NOT the reset button as this normally
> protects the hard drive from corruption.
dirty shutdown. If it were handled by the firmware, it could be
difficult to shut down a battery powered device which had locked up.
RESET should be more gentle than a long press.
Typically, power supplies will not have decayed before any sector write
in progress has completed and disks should park. However, you are
basically relying on fault recovery mechanisms to protect the physical
media, and the low level formatting.
Journalling file systems may protect the basic file structure, but data
buffered in user space, and write back caches (OS and device) will not
get written and very few application designers will have designed them
to be completely safe against partially written files.
Consumer devices have to be tolerant of such abuses, but whenever you
start relying on fault recovery mechanisms, for normal operation, you
are on dangerous ground.
NY
Apr 9, 2017, 10:14:34 AM4/9/17
to
<k...@notreal.com> wrote in message
news:g0akec5be84fpoh2a...@4ax.com...
The office building where I worked had huge diesel-powered generator to cope
with power cuts. My office was near it, and I know it wasn't tested during
office hours for five years. One day there was a power cut that affected the
whole town, and the diesel engine fired up, amid a tremendous roar and lots
of filthy black smoke. Power returned for about a minute and then there was
a huge explosion and a jet of flames. Apparently the generator couldn't
handle the load, even with the engine working as hard as it could (a good
diesel grunt!) and something caught fire, igniting the diesel tank. Turned
out that it had been specced back in the days when there wasn't a PC on
every single person's desk, and it was woefully underpowered for the modern
demands that were placed on it.
news:g0akec5be84fpoh2a...@4ax.com...
with power cuts. My office was near it, and I know it wasn't tested during
office hours for five years. One day there was a power cut that affected the
whole town, and the diesel engine fired up, amid a tremendous roar and lots
of filthy black smoke. Power returned for about a minute and then there was
a huge explosion and a jet of flames. Apparently the generator couldn't
handle the load, even with the engine working as hard as it could (a good
diesel grunt!) and something caught fire, igniting the diesel tank. Turned
out that it had been specced back in the days when there wasn't a PC on
every single person's desk, and it was woefully underpowered for the modern
demands that were placed on it.
MJC
Apr 9, 2017, 10:34:09 AM4/9/17
to
In article <V-KdnUieLtZb3HfF...@brightview.co.uk>,
m...@privacy.net says...
tested regularly. When eventually needed it ran for a few minutes and
then ran out of fuel. The protocol didn't include top-ups!
Mike.
m...@privacy.net says...
>
> The office building where I worked had huge diesel-powered generator
to cope
> with power cuts. My office was near it, and I know it wasn't tested during
> office hours for five years. One day there was a power cut that affected the
> whole town, and the diesel engine fired up, amid a tremendous roar and lots
> of filthy black smoke. Power returned for about a minute and then there was
> a huge explosion and a jet of flames. Apparently the generator couldn't
> handle the load, even with the engine working as hard as it could (a good
> diesel grunt!) and something caught fire, igniting the diesel tank. Turned
> out that it had been specced back in the days when there wasn't a PC on
> every single person's desk, and it was woefully underpowered for the modern
> demands that were placed on it.
Conversely the possibly apocryphal story I heard had the generator
> The office building where I worked had huge diesel-powered generator
to cope
> with power cuts. My office was near it, and I know it wasn't tested during
> office hours for five years. One day there was a power cut that affected the
> whole town, and the diesel engine fired up, amid a tremendous roar and lots
> of filthy black smoke. Power returned for about a minute and then there was
> a huge explosion and a jet of flames. Apparently the generator couldn't
> handle the load, even with the engine working as hard as it could (a good
> diesel grunt!) and something caught fire, igniting the diesel tank. Turned
> out that it had been specced back in the days when there wasn't a PC on
> every single person's desk, and it was woefully underpowered for the modern
> demands that were placed on it.
tested regularly. When eventually needed it ran for a few minutes and
then ran out of fuel. The protocol didn't include top-ups!
Mike.
Vir Campestris
Apr 9, 2017, 1:09:34 PM4/9/17
to
On 09/04/2017 15:34, MJC wrote:
> Conversely the possibly apocryphal story I heard had the generator
> tested regularly. When eventually needed it ran for a few minutes and
> then ran out of fuel. The protocol didn't include top-ups!
The one I know of is where the fuel pump was on the non-maintained
> Conversely the possibly apocryphal story I heard had the generator
> tested regularly. When eventually needed it ran for a few minutes and
> then ran out of fuel. The protocol didn't include top-ups!
mains. All the tests were fine. But when the power went off for real so
did the fuel pump...
BTW I use 30 seconds too. 30 odd years of computers here, quite often
dealing directly with the HW designers so I could write the tests.
Andy
Benderthe.evilrobot
Apr 9, 2017, 2:50:47 PM4/9/17
to
"David Woolley" <da...@ex.djwhome.demon.invalid> wrote in message
news:ocdcd6$mn5$1...@dont-email.me...
> On 09/04/17 10:01, Brian Gaff wrote:
>> If that
>> fails, then hold in the power button, NOT the reset button as this
>> normally
>> protects the hard drive from corruption.
>
> As I understand it, a long press is handled by the hardware and forces a
> dirty shutdown. If it were handled by the firmware, it could be difficult
> to shut down a battery powered device which had locked up. RESET should be
> more gentle than a long press.
AIUI: A short press is one way of a normal shutdown - sometimes you have to
>> If that
>> fails, then hold in the power button, NOT the reset button as this
>> normally
>> protects the hard drive from corruption.
>
> As I understand it, a long press is handled by the hardware and forces a
> dirty shutdown. If it were handled by the firmware, it could be difficult
> to shut down a battery powered device which had locked up. RESET should be
> more gentle than a long press.
press it a little longer...................
Benderthe.evilrobot
Apr 9, 2017, 2:54:43 PM4/9/17
to
<k...@notreal.com> wrote in message
news:sg5jeclipaol2ejgd...@4ax.com...
designs.
It does sometimes happen - pretending it doesn't won't save you.
k...@notreal.com
Apr 9, 2017, 7:15:16 PM4/9/17
to
cycles and a lot more system designers have been burned and learned.
>
>It does sometimes happen - pretending it doesn't won't save you.
Of course. There are morons designing stuff all the time. Worse,
>It does sometimes happen - pretending it doesn't won't save you.
there are companies that don't care that they're making crap.
avag...@gmail.com
Apr 10, 2017, 6:13:25 PM4/10/17
to
one opinion on electronics wear/degrade, is a function of thermal stress
Stephen
Apr 11, 2017, 2:51:34 PM4/11/17
to
doesnt keep files in a "safe" state?
Even some working apps dont leave files in a consistent state while
idle (although agreed that is bad design).
Less said about malware busy scribbling all over your drive to
maximise the chance of coming back to life after a reboot the
better...
The point is that an operating system cannot make assumptions about
what programs are trying to do and having "well formed" behaviour -
they need to try to be robust no matter what is mucking around, while
a disk is full and a drive is trying to remap to sort out bad sectors.
the same hardware build - when it is too late to find out it didnt get
recorded correctly if you only have 1 machine (or 2 with different
builds)......
>>
>>Moral of the story: always try any new hardware during the warranty period!
>
And keep the old one as a fallback....
>>Moral of the story: always try any new hardware during the warranty period!
>
>Anything that's important has to be tested.
Replace xyz with ntl to reply
Stephen
Apr 11, 2017, 2:52:25 PM4/11/17
to
On Sun, 9 Apr 2017 15:34:01 +0100, MJC <gra...@mjcoon.plus.com>
wrote:
We had one where someone spoofed the guage and drained the tank.
>
>Mike.
wrote:
>
>Mike.
jurb...@gmail.com
Apr 12, 2017, 12:01:49 AM4/12/17
to
>"Of course. There are morons designing stuff all the time. Worse,there are companies that don't care that they're making crap."
Worse is that of companies, at least in consumer electronics WANT them to fail. I have seen examples that are pretty sure. Like in the five volt power supply they have an extras AC feedback loop which can only make the line vary. I beleive they did it corrupt the software. But then you could get the software "update" but wouldn't they just use better capacitors, or not do anything else ? I could find the reference to it under duress, but I am saying that they spend extra copper on the board to put certain caps near the vertical IC.
Like people say the government does so many stupid things, For some of them, they have a reason.
I have also seen alot of shit in audio like that. And this did not start yesterday either. I think they want(ed) to keep their jobs, so some units must fail. Their paychecks come from the sale of new units. Same with management.
It really comes down to screwing the People.
Worse is that of companies, at least in consumer electronics WANT them to fail. I have seen examples that are pretty sure. Like in the five volt power supply they have an extras AC feedback loop which can only make the line vary. I beleive they did it corrupt the software. But then you could get the software "update" but wouldn't they just use better capacitors, or not do anything else ? I could find the reference to it under duress, but I am saying that they spend extra copper on the board to put certain caps near the vertical IC.
Like people say the government does so many stupid things, For some of them, they have a reason.
I have also seen alot of shit in audio like that. And this did not start yesterday either. I think they want(ed) to keep their jobs, so some units must fail. Their paychecks come from the sale of new units. Same with management.
It really comes down to screwing the People.
jurb...@gmail.com
Apr 12, 2017, 12:09:19 AM4/12/17
to
>">>Moral of the story: always try any new hardware during the warranty period!
>
And keep the old one as a fallback."
Guilty. I bought a bunch of laptops and one stayed in the box past the warranty. I have had people try that so many times that I didn't even bother calling them, I just shelfed it. Luckily later, I got to use some of the parts.
>
And keep the old one as a fallback."
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