HDD issues.

[Spork Schivago]

Re: HDD issues.

I think there's bad sectors on the drive, not so much the heads, because I can read the other partitions just fine. Maybe some dust or something? I think the reason it drops down is because when it can't read the data, it tries a bit slower. I might be totally wrong though Keeney123. Definitely not a hard drive expert, but I do know a good bit about PCs.

[keeney123]

Re: HDD issues.

I think there's bad sectors on the drive, not so much the heads, because I can read the other partitions just fine. Maybe some dust or something? I think the reason it drops down is because when it can't read the data, it tries a bit slower. I might be totally wrong though Keeney123. Definitely not a hard drive expert, but I do know a good bit about PCs.

It is too bad they just don't remember the bad sectors and skip them the need time you read them so that the drive would still be usable.

[ChaosLegionnaire]

Re: HDD issues.

that wont work and is just pointless on a failing drive because the bad sectors would just keep increasing and increasing. it can no longer store data reliably. what is the point in continuing to use such a drive? russian roulette with your data? no thx and no spinning pun intended.

[stj]

Re: HDD issues.

It is too bad they just don't remember the bad sectors and skip them the need time you read them so that the drive would still be usable.

Linux can do that, it's called badblock remapping.
but as Chaos said, it's only going to get worse - usually at an accelerating rate.

[keeney123]

Re: HDD issues.

Linux can do that, it's called badblock remapping.
but as Chaos said, it's only going to get worse - usually at an accelerating rate.

That is interesting because the hard disk just holds magnetism in it. I wonder what the failure analysis reports are on that? Magnetic tape has a life expectancy of 30 to 100 years. I wonder why a hard disk would have a shorter time?

[stj]

Re: HDD issues.

if you open failed ones you would know.

usually there is an area on the platter with the coating rubbed away like a ring.
i could be where the swapfile was stored, or it could be where a regularly used file resides.
whatever the cause, the head must get worn down too.

i know drive makers write the firmware to scatter data across the drive to try to stop this happening.

however, this can cause issues with smooth reading on slow drives, so the firmware does exactly the opposite and tries to write files in continuous blocks on AV drives designed for PVR's

WD's AV-GREEN series are a good example of this.

[Spork Schivago]

Re: HDD issues.

It is too bad they just don't remember the bad sectors and skip them the need time you read them so that the drive would still be usable.

Yeah, I believe that's how it's supposed to work. The drive marks a sector bads and tries to move the data to a non-damaged sector on the drive. Or at least, that's what I remember from back in the day. Don't know where I got that information from though, it could of been from college or just an idea my friends and I came up with.

In this case, I kinda need the data in the damaged sectors. One of the sectors contains the hibernation file. When I try copying that file manually, it errors out. I'm gonna restart the PC and see if the drive drops back down to UDMA / 33 mode. Just running ddrescue the second time took longer than the first time.

[Spork Schivago]

Re: HDD issues.

if you open failed ones you would know.

usually there is an area on the platter with the coating rubbed away like a ring.
i could be where the swapfile was stored, or it could be where a regularly used file resides.
whatever the cause, the head must get worn down too.

i know drive makers write the firmware to scatter data across the drive to try to stop this happening.

however, this can cause issues with smooth reading on slow drives, so the firmware does exactly the opposite and tries to write files in continuous blocks on AV drives designed for PVR's

WD's AV-GREEN series are a good example of this.

I've torn a few apart for the magnets before and it was crazy what I found. One time, giant scratch on one of the platters. I think the head crashed and then scratched the platter. We were told in college that dust is generally to small to get into a hard drive but smoke isn't. Cigarette smoke, marijuana smoke, etc can get into the hard drive and that causes all kinds of damage. I know I have a friend that smokes around his laptop and he goes through hard drives like a kid eating halloween candy. Just a little bit of dust would wreak havoc I'd think. I guess that's why when data recover places work on drives, they do it in a clean room.

[Spork Schivago]

Re: HDD issues.

Have you guys heard anything about the WD Red drives? They come with a 5 year warranty I think. I believe they consider them "Enterprise" edition hard drives. You know, meant for a lot of wear and tear. Any of you guys ever try them yet? I always seemed to like the WD blacks. Had good luck with them.

[Uniballer]

Re: HDD issues.

Have you guys heard anything about the WD Red drives? They come with a 5 year warranty I think. I believe they consider them "Enterprise" edition hard drives. You know, meant for a lot of wear and tear. Any of you guys ever try them yet? I always seemed to like the WD blacks. Had good luck with them.

I have not used the Red drives, but I have some Re's, and I like them.

WD Red drives have a 3 year warranty. They are not really enterprise drives. WD says, "WD Red NAS hard drives are recommended for use in home and small office 1-8 bay NAS systems." WD rates them at 1 million hours MTBF. Here is one review of the 4tb Red drive.

WD Red Pro drives have a 5 year warranty.

WD Re drives have a 5 year warranty. They are enterprise drives. WD says they are rated for 2 millions hours MTBF and "Designed to handle workloads up to 550 TB per year".

Note that the BackBlaze reports do not indicate that enterprise drives have fewer failures in their use case (mostly being written to until they are full then spinning with few accesses until somebody needs to restore a backup). This does not mean they don't last longer for their intended purpose (24/7 data transfers).

[stj]

Re: HDD issues.

WD red and black are the same drive with different firmware.
the black will constantly re-try on errors for as long as it takes, the red will try a few times and then just report an error.

red are for raid systems - black will cause problems in raid if there is a read error.

[fzabkar]

Re: HDD issues.

i know drive makers write the firmware to scatter data across the drive to try to stop this happening.

however, this can cause issues with smooth reading on slow drives, so the firmware does exactly the opposite and tries to write files in continuous blocks on AV drives designed for PVR's

WD's AV-GREEN series are a good example of this.

The firmware doesn't "scatter" any data. The OS determines where the data are written. AV drives incorporate the ATA Streaming feature set which allows the drive to skip difficult sectors whereas a typical desktop drive will become bogged down with error recovery. The philosophy is that AV applications can tolerate missed video frames or audio dropouts.

[stj]

Re: HDD issues.

the firmware does scatter the data, the sectors are not hard mapped like the old days.

[fzabkar]

Re: HDD issues.

the firmware does scatter the data, the sectors are not hard mapped like the old days.

No, the data are laid down in serpentine fashion, from the outer zones to the inner zones. The only thing that is different from "the old days" is that drives use LBA translation rather than CHS mode.

If you examine a HD Tune read benchmark graph, you will see that the transfer rate monotonically decreases from the outer tracks to the inner tracks. That proves that the data are laid down in LBA order. In fact, at high resolutions you can see the actual steps between zones. At even higher resolutions you can see the serpentine segments.

Measuring hard drive RPM:
http://www.hddoracle.com/viewtopic.php?f=59&t=149&p=268

HDD from inside: Tracks and Zones:
http://hddscan.com/doc/HDD_Tracks_and_Zones.html

[Uniballer]

Re: HDD issues.

WD red and black are the same drive with different firmware.

Pretty sure it is the Red and Green that are the same drive with different firmware.

[fzabkar]

Re: HDD issues.

In this case, I kinda need the data in the damaged sectors. One of the sectors contains the hibernation file. When I try copying that file manually, it errors out.

You could try Bad Block Copy for Windows:

http://alter.org.ua/soft/win/bb_recover/

It functions like ddrescue, but at the file level.

[fzabkar]

Re: HDD issues.

I think there's bad sectors on the drive, not so much the heads, because I can read the other partitions just fine. Maybe some dust or something? I think the reason it drops down is because when it can't read the data, it tries a bit slower.

These days head degradation is a very common problem. That's because the heads have resistive read elements which become weak when they are damaged by "head slaps". In the very old days heads had read/write coils, so bad sectors were nearly always related to media faults. Nowadays bad sectors are very often due to head faults. Some drives have a serial diagnostic port over which they are able to report the head resistances and a great many other things.

The following thread may help you understand what goes on during error correction:

Error Correction and Read Retry Operations:
http://www.hddoracle.com/viewtopic.p...&t=1133&p=5128

I would recommend a SMART tool such as CrystalDiskInfo. Look for reallocated, pending, or uncorrectable sectors.

http://crystalmark.info/software/Cry...o/index-e.html

[keeney123]

Re: HDD issues.

The firmware doesn't "scatter" any data. The OS determines where the data are written. AV drives incorporate the ATA Streaming feature set which allows the drive to skip difficult sectors whereas a typical desktop drive will become bogged down with error recovery. The philosophy is that AV applications can tolerate missed video frames or audio dropouts.

Actually were the data is written is a function of both the OS and the ROM chip in the hard-drive. If the ROM chip is pre-programed to scatter the data that is just what it will do in-spite of the OS telling it to write to a particular address. Some hard drive makers to not have such a set up and allow the OS to dictate where the data on the disk is.

[fzabkar]

Re: HDD issues.

Pretty sure it is the Red and Green that are the same drive with different firmware.

I tried to make sense of WD's marketingspeak in this thread at WD's forum:

http://community.wd.com/t5/Desktop-M...ed/td-p/840798

ISTM that WD spends more time in the marketing department than the lab.

For example, a consumer grade 5400 RPM ("IntelliPower") HDD gets enterprise-class spindle motor balancing, whereas an enterprise grade 7200 RPM HDD is limited to a Stabletrac (tm) screw. Bizarre.

[fzabkar]

Re: HDD issues.

Actually were the data is written is a function of both the OS and the ROM chip in the hard-drive. If the ROM chip is pre-programed to scatter the data that is just what it will do in-spite of the OS telling it to write to a particular address. Some hard drive makers to not have such a set up and allow the OS to dictate where the data on the disk is.

The ROM does not decide where the data goes. No drive "scatters" data. The OS tells the drive to write to LBA n, and the drive then writes to LBA n. However, the drive has a "translator" which determines how the logical blocks are mapped to the drive's physical CHS addresses. Even so, the data are still laid down in serpentine fashion, in LBA order, except for the grown defects. Please read the Tracks and Zones article. It was written by a Seagate employee who is a highly regarded member of the data recovery community.