Question test HDD files

[A Computer Guy]

A fair point. That advantage is still outweighed by the drawbacks, imo.

One has to pick and choose based on the pros and cons and resources manageable by the user.

 

[AusWolf]

One has to pick and choose based on the pros and cons and resources manageable by the user.

For long term storage, I'd choose safety over transfer speed / minimising file system overhead, but each to their own.

 

[nageme]

I think in 7zip you can also do storage mode without compression

Like most compressors, including RAR, ZIP, ACE...
There's also the classic compressionless archiver TAR, though it's less comfortable.

For long term storage, I'd choose safety over transfer speed / minimising file system overhead

Can be both.

 

[AusWolf]

Can be both.

How?

 

[A Computer Guy]

How?

Multiple copies.

 

[AusWolf]

Multiple copies.

Sure, but with 4 copies on 4 drives, you just need a random single corrupted bit on each drive to lose all of your data forever.

By keeping files separate (uncompressed), you need the exact same bit to be corrupted on each drive to lose just one of your files.

Needless to say, the second option is infinitely safer.

 

[nageme]

For long term storage, I'd choose safety over transfer speed / minimising file system overhead

Can be both.

How?

If not RAID, or multiple copies, there are also two other options mentioned earlier:

I would still lean towards using PAR files alongside the archive instead of using the RAR recovery record

 

[A Computer Guy]

Sure, but with 4 copies on 4 drives, you just need a random single corrupted bit on each drive to lose all of your data forever.

By keeping files separate (uncompressed), you need the exact same bit to be corrupted on each drive to lose just one of your files.

Needless to say, the second option is infinitely safer.

The risk of that is mitigated by the number of copies one is willing to keep. One can go down an infinite rabbit hole of scenarios for safety but most people have to stop at what is practical for them in terms of risk management, cost, and time. I can't approach the probability of the scenario you described but I would say it could be managed in a way one would be likely to never encounter it.

 

[nandobadam]

When a large file (150GB) rar zip or 7z is created, is it possible to use another alternative tool (or Winrar itself) to create a recovery record to repair in case any bit becomes corrupted and renders the entire compressed file useless? If the need arises and it takes a long time to unpack all the files that are inside the larger file? What are the possibilities for protection without internally modifying the compressed file created?

Is it easy to corrupt files on 2.5" HDDs even during storage of a HDD that will be used rarely?

 

[AusWolf]

When a large file (150GB) rar zip or 7z is created, is it possible to use another alternative tool (or Winrar itself) to create a recovery record to repair in case any bit becomes corrupted and renders the entire compressed file useless? If the need arises and it takes a long time to unpack all the files that are inside the larger file? What are the possibilities for protection without internally modifying the compressed file created?

The best recovery record is another copy of the file on another drive, imo. Although, there are tools that create checksums to check for data integrity. I'm not really an expert on those, to say the least, so I'll stop here.

Is it easy to corrupt files on 2.5" HDDs even during storage of a HDD that will be used rarely?

This question has been answered multiple times.

HDDs aren't meant for long-term storage, they have to be turned on and their data read regularly to avoid demagnetisation of the discs. Do that every couple of months, and you're fine.

Please, don't keep asking the same thing again and again.

 

[nageme]

HDDs aren't meant for long-term storage, they have to be turned on and their data read regularly to avoid demagnetisation of the discs.

Any references to that?

I think HDDs are pretty fine for archival storage.
Yeah, don't leave them in a drawer for 15 years, but I wouldn't be too worried about a year or two or three.
They don't "demagnetize". And even if they did, turning them on doesn't refresh the data.
The main reason I see for turning them on would be the motor.

Do that every couple of months, and you're fine.

No need to turn on every few months.

When a large file (150GB) rar zip or 7z is created

I think 150GB is larger than practical, except in special circumstances.

What are the possibilities for protection without internally modifying the compressed file created?

As mention before: PAR.

https://github.com/Yutaka-Sawada/MultiPar
http://www.quickpar.org.uk/

 

[AusWolf]

Any references to that?

I think HDDs are pretty fine for archival storage.
Yeah, don't leave them in a drawer for 15 years, but I wouldn't be too worried about a year or two or three.
They don't "demagnetize". And even if they did, turning them on doesn't refresh the data.
The main reason I see for turning them on would be the motor.

Here is a random article I just found. I haven't read on the topic recently, so I don't know any other references from the top of my head.

Turning a HDD on won't remagnetise every sector, that's true. That's why I'd at least do a full surface scan every now and then.

No need to turn on every few months.

Better safe than sorry, imo.

As mention before: PAR.

https://github.com/Yutaka-Sawada/MultiPar
http://www.quickpar.org.uk/

That looks like a great tool! Is there a Linux equivalent by any chance?

 

[Shrek]

HDDs aren't meant for long-term storage, they have to be turned on and their data read regularly to avoid demagnetisation of the discs. Do that every couple of months, and you're fine.

How does turning on help, the drive would just sit there.

 

[AusWolf]

How does turning on help, the drive would just sit there.

HDDs aren't meant for long-term storage, they have to be turned on and their data read regularly to avoid demagnetisation of the discs. Do that every couple of months, and you're fine.

That's why I said I'd do at least a surface check every now and then.

 

[nandobadam]

Thank you for sharing your knowledge with me.

You said that just turning on the HDD does not remagnetize the magnetic disks and you recommended a surface scan. Does this surface scan need to be a full scan or can Quickscan be used to magnetize the entire HDD?

Does the surface scan need to be performed once every two months or once a year?

When there is a loss of magnetization on a 2.5" HDD, is this loss permanent or can it be recovered with a surface scan? For example, if a new HDD has 100% magnetization, if it remains without power for a few years and loses 20%, can the 20% that was lost be recovered with a surface scan?

 

[Shrek]

A surface scan will check for bad sectors, but I don't see how it will help with magnetization.

 

[AusWolf]

Thank you for sharing your knowledge with me.

You said that just turning on the HDD does not remagnetize the magnetic disks and you recommended a surface scan. Does this surface scan need to be a full scan or can Quickscan be used to magnetize the entire HDD?

Does the surface scan need to be performed once every two months or once a year?

When there is a loss of magnetization on a 2.5" HDD, is this loss permanent or can it be recovered with a surface scan? For example, if a new HDD has 100% magnetization, if it remains without power for a few years and loses 20%, can the 20% that was lost be recovered with a surface scan?

There is no hard rule here. I'd do the full surface scan just to be on the safe side.

A surface scan will check for bad sectors, but I don't see how it will help with magnetization.

I've read somewhere that if a bit is starting to lose its charge, but is still readable, then the drive can correct it to a full 0 or 1 again. (someone prove me right or wrong)

 

[Shrek]

Maybe so, I'd be interested to know.

 

[nageme]

Reading the whole drive will not rewrite it.

Drives reallocate sectors only if they're in an explicitly bad state. These are reflected in SMART's 0x05 Reallocated Sector Count.
Suspect sectors are 0xC5 Pending Sector Count, and probably won't be reallocated until they're rewritten by the host.
Other than reallocating, I don't think drives rewrite sectors automatically.

The situation is different in SSDs, but the topic here is HDDs.

Here is a random article

That's just a vague marketing article from a UK PC repair biz.
Looks like a random composition of an answer from superuser.com (the link is referenced there), and LLM-style text (maybe from another random source: a data recovery biz in the UK).
It also provides as "reference" a NY Times article from 2004...

That looks like a great tool! Is there a Linux equivalent by any chance?

I don't know. I'm not a Linux user, but my impression is that it's still surprisingly lacking in many basic GUI tools.
For PAR I'm mainly finding old and limited-looking ones like gpar2 or Kpar.

Perhaps WINE + one of the Windows tools is an alternative.

 

[anonuser57]

When there is a loss of magnetization on a 2.5" HDD, is this loss permanent or can it be recovered with a surface scan? For example, if a new HDD has 100% magnetization, if it remains without power for a few years and loses 20%, can the 20% that was lost be recovered with a surface scan?

At this point you need to read the Wikipedia article on hard drives because that question is just too nonsensical.

The answer to your original question is that how easily a HDD loses data depends on when it was made. From the late 90' through the 2000s drives get progressively worse with data retention. Until a change in the late 2000s early 2010s in how HDDs are made fixed that issue. The way to ensure you don't lose data is to do integrity checks and copy the data to another drive. A modern HDD will keep your data intact for at least a decade but you should do the checks every year so that you don't forget.

 

[nandobadam]

Is rewriting what maintains the HDD's magnetism? Does surface testing rewrite?

Is there a big difference between the magnetism of old HDDs and modern HDDs from 2010 onwards?

Does Winrar's "test" mode, which performs a corruption test, activate and restore magnetism?

 

[DirtyDingusMcgee]

No
No
No
and
No

Magnetic storage has been around for nearly 100 years. It can be learned about.

https://en.wikipedia.org/wiki/Magnetic_storage

https://computer.howstuffworks.com/removable-storage.htm

https://hasonss.com/blogs/magnetic-...whg335eZQSfpdgwlDr31m8rGBdfHl-uVNNuwQnU3et20w

https://cs.stanford.edu/people/nick/how-hard-drive-works/

https://www.maths.tcd.ie/~nora/DT315-1/Storage Devices.pdf

Search engines are your friend. Have we not closed this damn thread yet?

 

[the54thvoid]

Thread closed. OP is abusing the good nature of the forum. I've no idea what they want, why they constantly recycle the same question, or why they feel they need to ask multiple questions with each post.

OP - you have been given plenty of responses, and they have answered your question.