VOGONS


First post, by JanTwo

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Hello everybody!

Recently we've had a blackout. My Fujitsu V6535 (buildt 2009) has a shtty battery (100 to 0% in 10 secs), so it was powered-off a little rude. There was no thunderstorm, excess voltage or whatsoever - it just went off like a desktop PC when pulling the plug. Weeks later chkdsk found a (the first and only) single bad sector (still original HD, runtime +/- 10.000 hrs). Since i am not sure if the blackout was responsible for this, i stressed the HD like mad, copied and moved tons of files, wiped, formated and fdisked partitions, changed FAT32 to ntfs and vice versa - but could not produce further errors.

Before spoiling a replacement HD i better ask: Was the timing of blackout + error only a coincidence, or can a simple cold power-off most likely cause a headcrash? If yes: Are bigger / smaller / younger / older / 5200RPM / 7400RPM HDs more sensitive than others? Are SSDs as sissy? Thanks for replies!

edit: Forgot that bit: When the computer was off-current for several days, the battery it at 0%. I have to wait 15 mins before switching it on, else the power-adapter does not deliver enaugh power for booting and loading at the same time. So there might be fluctuations in voltage. Solution: Throw everything in the bin?

Last edited by JanTwo on 2022-01-13, 18:38. Edited 1 time in total.

Reply 1 of 10, by TrashPanda

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Modern desktop spinning rust drives usually have a small capacitor backup that lets them park the heads if a power failure happens but .. no idea if laptop drives have this ability so its possible the blackout caused the bad sector but if it was a head crash I would expect more than just one bad sector so im leaning to it being a coincidence.

Oh noes, the cap let the shmooo out 😁

Reply 2 of 10, by darry

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My (possibly dated and/or erroneous) understanding of mechanical HDD head retraction is that, upon power loss, the kinetic energy of the still spinning platters is typically used to safely retract heads through the use of a purposefully designed mechanical coupling .

AFAICR, a drawback of that type of system is that if power is cut while the platters are not spinning at nominal velocity (either because the drive was just powered on or because several brief power on/off events occurred in a short enough timeframe), there may not be enough kinetic energy in the spinning platters to properly retract the heads .

Please correct me if I am completely wrong or if this is no longer true for more recent designs .

EDIT : @Trash Panda Do you know when that kind of capacitor-backed mechanism might have become commonplace on consumer drives ?

Reply 3 of 10, by JanTwo

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darry wrote on 2022-01-13, 18:42:

EDIT : @Trash Panda Do you know when that kind of capacitor-backed mechanism might have become commonplace on consumer drives ?

I know that my first "notebook", a 386SX20 40MB HD already had a "parking function". They advertised that (around 1992?)

Last edited by Stiletto on 2022-01-13, 20:21. Edited 1 time in total.

Reply 4 of 10, by TrashPanda

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darry wrote on 2022-01-13, 18:42:
My (possibly dated and/or erroneous) understanding of mechanical HDD head retraction is that, upon power loss, the kinetic energ […]
Show full quote

My (possibly dated and/or erroneous) understanding of mechanical HDD head retraction is that, upon power loss, the kinetic energy of the still spinning platters is typically used to safely retract heads through the use of a purposefully designed mechanical coupling .

AFAICR, a drawback of that type of system is that if power is cut while the platters are not spinning at nominal velocity (either because the drive was just powered on or because several brief power on/off events occurred in a short enough timeframe), there may not be enough kinetic energy in the spinning platters to properly retract the heads .

Please correct me if I am completely wrong or if this is no longer true for more recent designs .

EDIT : @Trash Panda Do you know when that kind of capacitor-backed mechanism might have become commonplace on consumer drives ?

Seems I wasn't totally right about the capacitor reserve, some modern drives use a method where the heads dont land on the drive platters when parking and instead are removed from the platter area by a magnetic parking platform, others use a method you suggest, I remember reading about the capacitor backup that allows the heads to finish moving away from the platters during a power outage but I cant remember where, it might be part of the system that removes the heads from the platters via the parking platform and I have simply confused it for its own system when its part of a bigger one.

https://www.datarecoverytools.co.uk/data-reco … ing-of-rw-head/

This site lists the methods being used currently.

Oh noes, the cap let the shmooo out 😁

Reply 5 of 10, by verysaving

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Power loss CAN cause bad sectors (it's stated into most HD datasheets).
They are soft bad sector, that means they are not actually bad sectors
but data and checksum doesn't match. They could be easily fixed by Simply
rewriting them.

Run a scan with HDAT2 (https://www.hdat2.com/), if it's a soft bad sector
it will be fixed with no problem, but chkdsk will always report it as bad
sector; it fixes only logical file system issues (and if you have serious
physical error on the drive will just add some trouble...)

BTW what's the model of the hard disk?
Can you post a SMART log?

Reply 6 of 10, by debs3759

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verysaving wrote on 2022-01-14, 01:28:

Run a scan with HDAT2 (https://www.hdat2.com/)

Looks useful, thanks for the link

See my graphics card database at www.gpuzoo.com
Constantly being worked on. Feel free to message me with any corrections or details of cards you would like me to research and add.

Reply 7 of 10, by Zup

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Three suggestions:
- My old Fujitsu laptop had a depleted CR2032 battery. This caused boot problems (black screen, HDD detection errors, but never complained about CMOS values). Maybe you should check that.
- If you replace CMOS battery and the computer still have boot problems, you should run it without main battery. Your battery may be putting extra workload on your PSU, and may cause it to fail.
- Check the SMART parameters of your disk. Usually, by the time chkdsk/SanDisk catch a bad block, the hard disk has silently reallocated many others. If the reallocated count and the pending reallocation is 0, probably it was a glitch (and HDAT2 will cure it). If not... well your HDD is not trustworthy.

I have traveled across the universe and through the years to find Her.
Sometimes going all the way is just a start...

I'm selling some stuff!

Reply 8 of 10, by Horun

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If I had a blackout it could lead to a head crash ;p
Think your situation is a coincidence..

Hate posting a reply and then have to edit it because it made no sense 😁 First computer was an IBM 3270 workstation with CGA monitor.

Reply 9 of 10, by JanTwo

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Good news! Now i can force the computer to generate more bad sectors: When trying to boot while the flat battery is charging, i get the Windows splash-screen, a min later it stops and i see the bluescreen = not enaugh voltage or Watt. When booting with full or removed battery, everything works.

Strange: chckdsk now reports 28 bad sectors kb (512 bytes per sector) (1 old, 27 today) on vol f:, but SMART (CrystalDisk, SIW & Defraggler) seems not detect anything. Also, the used area in Defraggler was red before, today it looks blue = clean (???).

However, i will have to replace the battery before changing the HD visit ebay for a new 30 Euros-notebook.

edit: mixed up things (as usual).

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Last edited by JanTwo on 2022-01-14, 15:14. Edited 2 times in total.