HDD issues.

[Spork Schivago]

Re: HDD issues.

Thank you.

[Per Hansson]

Re: HDD issues.

I split off the SSD discussion into this new thread:
https://www.badcaps.net/forum/showthread.php?t=49114

[Spork Schivago]

Re: HDD issues.

I'm not aware of any modern file system that doesn't allow for fragmentation, but then I haven't looked much beyond Microsoft. In fact that last time I saw a file system that would only write files in contiguous space was in the 1980s.

PATA has a speed limit related to the selected UDMA mode whereas SATA can transfer data at a much faster rate, especially for SSDs. You would only use IDE compatibility mode for legacy OS-es or in the absence of a suitable SATA driver. For example, some HDD manufacturers' firmware updates are delivered via DOS based utilities which sometimes have trouble communicating in SATA mode.

As for glass platters, the data recovery guys often relate horror stories about shattered platters, or platters that have suffered a prolonged head crash, to the point that all the oxide has been scraped off and the platters have become transparent.

https://upload.wikimedia.org/wikiped...iled_Disks.png
http://www.nitroware.net/images/stor.../deskstar2.jpg

I guess the way I worded it was incorrect. Technically, fragmentation in Linux can happen, but the file system, like ext 2, 3, 4, etc, will automatically take care of it when it happens. Here's a decent article that talks about why we don't need to defrag in Linux and why Linux distros don't come with defragmentation

http://www.howtogeek.com/115229/htg-...defragmenting/

It's a little old, 2012 I think, but it's still valid. I'm not sure how the newer file systems in Linux deal with fragmentation, like Btrfs (B-Tree File System or Binary Tree File System).

[fzabkar]

Re: HDD issues.

I'm not aware of any modern file system that doesn't allow for fragmentation, but then I haven't looked much beyond Microsoft. In fact that last time I saw a file system that would only write files in contiguous space was in the 1980s.

PATA has a speed limit related to the selected UDMA mode whereas SATA can transfer data at a much faster rate, especially for SSDs. You would only use IDE compatibility mode for legacy OS-es or in the absence of a suitable SATA driver. For example, some HDD manufacturers' firmware updates are delivered via DOS based utilities which sometimes have trouble communicating in SATA mode.

As for glass platters, the data recovery guys often relate horror stories about shattered platters, or platters that have suffered a prolonged head crash, to the point that all the oxide has been scraped off and the platters have become transparent.

https://upload.wikimedia.org/wikiped...iled_Disks.png
http://www.nitroware.net/images/stor.../deskstar2.jpg

[Spork Schivago]

Re: HDD issues.

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.

Oh man! I got my picture taken with the old VP of Seagate!! I put my arms around him like we was buddies and shit! I went to his daughter's wedding! She was marrying my friend and he picked me as his best man. They flew me (and I flew my now-wife) out to Australia for the wedding. It was insane. Never lived so rich!!! Just the motel alone we stayed in must of cost a grand a night! We went on this yacht for dinner, and they had a live band playing for us, it was insane! We ate out every night and the dad payed for it all! We found common ground, my home town, Corning. He said Seagate was trying to make a hard drive that had glass platters. They contacted Corning to make the glass but there was something wrong with the design and they couldn't work it out. I can't remember what. Maybe they where too heavy or they shattered at the fast speeds? I dunno. He was super intelligent though. I'll try to find the picture and if I can, I'll post it here.

[Spork Schivago]

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.

Yeah, isn't it the filesystem that determines where the data gets written? Aren't there fragment free filesystems out there? There's so many of them it's hard to keep track. I kinda liked where Btrfs was going. I wonder if that's stable now. I think some Linux distro's ship with it by default.

[Spork Schivago]

Re: HDD issues.

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).

Thank you for the correction! I've been out of the loop for a bit, working on other things besides PCs. Trying to do something different with my life and all that jazz.

[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.

[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.

[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.

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

[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.

[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.

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

[stj]

Re: HDD issues.

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

[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.

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.

[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).

[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.

[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.