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Author Topic: hard wire disconnect to turn off computer harmful?  (Read 11585 times)

Offline CZARCAR

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3 yr. old windows vista with chrome which runs miserably slow after coming off "sleep". i disconnected all power to shut off computer & modem & reconnected & started a few minutes later & it works much faster! especially the google chrome.
IS IT HARMFUL TO TURN THE COMPUTER ON & OFF WITH A HARDWIRE DISCONNECT?


 

Offline LeeE

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hard wire disconnect to turn off computer harmful?
« Reply #1 on: 03/02/2010 15:05:15 »
A "hardwire disconnect" isn't a term I recognise, but if you're just cutting the power without performing a system shutdown then you risk corrupting your filesystem.

What's wrong with simply shutting your system down, instead of putting it into hibernation, when you've finished using it?  You've got to do a full system start if you're just cutting the power anyway.
 

Offline CZARCAR

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hard wire disconnect to turn off computer harmful?
« Reply #2 on: 03/02/2010 15:19:28 »
thanx. i got pissed this morn & pushed the on/off switch on the powerstrip. i am more concerned with damage to the hardware. i've tried restart before but disconnect worked better + the page i was on was stuck/frozen. i used to bang the side of the b&w tv in the past but have yet to try on the computer.
 

Offline syhprum

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hard wire disconnect to turn off computer harmful?
« Reply #3 on: 06/02/2010 11:03:17 »
If I accidentally cut the power on my AMD/Windows 7 computer which I sometimes do it comes back with the suggestion that I start it normally and no harm seems to be done.
I did notice that one of my RW DVD disks has two small holes burnt in the surface limiting its capacity to 2GB, maybe this was caused by an incorrect shutdown ?.
 

Offline Geezer

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hard wire disconnect to turn off computer harmful?
« Reply #4 on: 06/02/2010 20:41:57 »
I suppose that's not impossible. The bigest risk is that if the OS happens to be writing a sector on the hard disk when the lights go out. If that sector happens to have critical disk allocation information in it, bad things might ensue. There is also a slightly higher risk that a head crash will carve a beautiful shiny helix on one of the platters in the drive.

I'm not sure if things are any better if you hold in the power button to force a powerdown. I suspect this might be a bit safer, but I really don't know.

Of course, if it was a really old computer, you did your best to never turn it off. Every power cycle had a rather high probability of blowing up a valve (tube) or transistor. It was hard to tell if they blew up on the way down, or on the way back up.

We used to have the memory map blackboard from EDSAC. The purpose of the blackboard was to let programmers know which bits of memory were currently working so they could relocate their programs to run in working memory. Such fun!
 

Offline syhprum

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hard wire disconnect to turn off computer harmful?
« Reply #5 on: 28/02/2010 20:46:51 »
CZARCAR

The reason why you had to bang the side of your valve type TV (not only B&W Some early colour TVs used valves) was corrosion on the valve pins.
The solution was to remove each valve, dunk the pins in WD40 and replace them in their sockets with a wiggle.
If you could get Russian valves they had gold plated pins that were much better.
When I first started working with HELL picture processing equipment they used huge great picture processing units with about 50 circuit boards and very poor quality sockets we had to do the same with all these.
 

Offline ukmicky

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hard wire disconnect to turn off computer harmful?
« Reply #6 on: 05/04/2010 14:31:19 »
Your PC also writes a file every time you shut down basically telling it how to load up. The writing of a fresh version allows the PC to take into account software and hardware changes and as its a new copy it is less likely to contain corrupt data.

If you turn it off at the plug and don't allow it to write a fresh file it will need to start up using a previous version which will sooner or later become corrupt and your PC will not start except in safe mode.
« Last Edit: 06/04/2010 20:06:38 by ukmicky »
 

Offline syhprum

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hard wire disconnect to turn off computer harmful?
« Reply #7 on: 13/04/2010 20:02:59 »
Any good quality computer PSU will have large capacitors on the mains voltage side that will hold up the power for a second or two allowing time for the disk drives and CPU to perform their vital shut down functions.
of course if the PSU is very heavily loaded with fancy video boards or many disk drives it might not quite make it.   
 

Offline Geezer

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hard wire disconnect to turn off computer harmful?
« Reply #8 on: 13/04/2010 21:34:09 »
Any good quality computer PSU will have large capacitors on the mains voltage side that will hold up the power for a second or two allowing time for the disk drives and CPU to perform their vital shut down functions.
of course if the PSU is very heavily loaded with fancy video boards or many disk drives it might not quite make it.  

That used to be true with good old series regulator power supplies, but switch mode regulators are almost universal now, and they tend to drop like a rock.
 

Offline syhprum

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hard wire disconnect to turn off computer harmful?
« Reply #9 on: 14/04/2010 13:47:03 »
I will run some tests on my PSU and measure how long the 12 & 5v holds up, how long do you think it is needed for and when will be considered to have dropped too far?.
 

Offline Geezer

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hard wire disconnect to turn off computer harmful?
« Reply #10 on: 14/04/2010 18:01:47 »
I will run some tests on my PSU and measure how long the 12 & 5v holds up, how long do you think it is needed for and when will be considered to have dropped too far?.

Good question! I'm not sure PC's even have a detection mechanism that would allow the OS to anticipate a power failure, so it may be academic.

The digital logic is usually guaranteed at plus or minus 5% of nominal supply voltage over the full temperature range, so that might be reasonable cutoff point.

BTW, the other big difference between switchers and series regulators is how slowly they ramp up to voltage. They are so slow that they can easily defeat poorly designed master reset circuits.
 

Offline CZARCAR

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hard wire disconnect to turn off computer harmful?
« Reply #11 on: 30/04/2010 12:09:21 »
i use google chrome but IE ran slow also. on a hunch i uninstalled GOOGLE DESKTOP which during the uninstall advized me that stuff was running in the background so i proceeded & this worked seemingly? also uninstalled old norton antivirus....computer runs much faster now online...thanx
 

Offline SeanB

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hard wire disconnect to turn off computer harmful?
« Reply #12 on: 01/05/2010 16:01:39 »
The pc power supply has an output to the mainboard labelled "power good" that is used to force a reset condition on the CPU and mainboard logic until the power supply outputs are stable on power up. It generally allows the CPU to start after around 2 mains cycles after switch on, or around 0.1 second, via a simple timing arrangement inside the PSU. On cheap supplies it stays active until the power rails decay during the main supply shutdown ( either because the mains failed/was disconnected or the computer requested the main supply off, with a standby power supply providing 5V for keeping the clock running and for allowing remote turn on/timed turn on). On more elaborate units it is goes inactive when the power supply is still able to provide regulation but the power will be going off in around 0.1 sec or less, and allows software ( which has to be built into the BIOS) to stop writing to disks and basically kills all software processes running very messily by halting the CPU and putting it to sleep, relying on the disk drives themselves having power fail detection to prevent damage as they are now essentially just spinning and not doing anything active when they lose power.

Pulling the plug is generally not going to be harmful unless the data being written was part of a core fileset, on Windows that being a massive set of files that are continuously being written to which hold the very fragile registry and core system files that store state information. Sometimes they get corrupted ( data is changed but the pointers did not get updated to the correct state or vice versa, or they point to random garbage) and sometimes the corruption is detected and fixed by the os on startup, but sometimes you get either a reboot loop or a BSOD on startup. This is a random process and may never appear, or can occur on the first time, YMMV greatly. Of course the OS itself can do the same at times, so this may be difficult to prove either way.

As to software and slow, you would be better off only having M$ 's free windows defender and uninstalling all other AV products. Most are bloatware and bottleneck all operations. Defender is no frills, but works reasonably enough as far as AV goes ( I use ClamAV, but then again I rarely use XP as the OS on my laptop, just use the filesystem as storage space mostly) and the price is right, you already paid for it.
« Last Edit: 01/05/2010 16:08:33 by SeanB »
 

Offline nicephotog

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hard wire disconnect to turn off computer harmful?
« Reply #13 on: 04/09/2010 10:20:10 »
Like was meantioned earlier, if you do anything other than a standard shutdown you risk corrupting your file-system.
I remember having an argument in here about that, because if you do, whether you start "normal" or "safe mode" in Win or any filesystem you should do a full CHKDSK /R/F on each volume but particularly the active partition.
 

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hard wire disconnect to turn off computer harmful?
« Reply #13 on: 04/09/2010 10:20:10 »

 

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