Basic question I have to ask is if you delete all of your recorded content on your HDD (doesn't matter what brand/model you have), is that the equivalent of defragmentating it?

If you have a SA 8300HD, the owner's thread tells you how to defrag the HDD. I do this every few months. When performance gets sluggish, this speeds things up a bit.

No because a defrag puts the existing stored hard drive programs one after the other on the hard drive instead of say a 2 hour program having 1hr partialy at one spot & the 2nd hour in another spot on the hard drive. Deleting all content just makes the future stored programs be one after the other until you delete a program, which then you have the possibilty of fragmentation afterwards.
Also what just deleting content doesn't do is check for bad sections on the disk, where as a defrag utility usually checks for these.

...(doesn't matter what brand/model you have)...The problem is due to the unknowns with the proprietary file systems in use on DVDRs, I think the answer may differ depending on the brand, and your understanding of the term "Defrag". I suspect some respondents are equating "defrag" with "format".

On a PC, when you defrag you just make sure none of the files on the drive are fragmented, (with portions stored in multiple separate locations rather than one contiguous block,) so if the drive is empty there is nothing to defrag, and therefore the drive is already "defragmented".

On my Pioneer, the defrag feature is called "optimize" and is pretty instantaneous when the drive is empty so I believe there is nothing done. This is an entirely separate thing from another feature called "Initialize HDD" which apparently resets the file system in the event of errors on the HDD. The "Initialize HDD" feature may format the drive and check for bad sectors, (I'm not sure as I have never needed it,) but I think it is important to point out there is a difference between the two and this is probably the case on most makes with a defrag feature.

On some older Panasonic and Toshiba models (perhaps without a defrag feature) it was necessary to "format" the HDD occasionally to avoid serious file system errors. This essentially reset the file system erasing the drive in the process so no fragmented files remained, so the result may have been the same regarding fragmentation, but there is a difference.

I suspect by the poll's results at the time I typed this, that many votes are from users that may not be making the distinction: Defragmenting/Optimizing is not the same thing as formatting/initializing although the both result in a drive without fragmentation. Defragging retains and reorganizes the existing files as opposed to erasing the drive and/or resetting the file system.

So, I think the correct answer depends on the brand/model, and whether or not there is a separate defrag feature that just defragments files like on a PC. If there is, then emptying the drive makes defragging redundant because there's nothing to defrag.

What you can do just to be sure is, every 6 months or so, after you've copied all good stuff from HD to DVD, go into the HDD management menu and select "Format Hard Drive". Instant defrag. Probably not much of a issue, although there may be minimal fragmentation on the HDD recorders that may occur after heavy usage, due to all the data being manipulated during editing, deleting, adding, thumbnails, index points, disc names, etc. When I've formatted the Hard drive I did not really see any speed improvement, can't hurt though.

If there are no files on the HD, then you have a "defragged" drive. So any action that removes the files from the drive essentially defrags it. Most recorders have an "erase all titles" or "erase disk" , that is the ultimate defrag.

If you defrag a drive with files on it, you are only joining any separated titles into one file. But that generally will accomplish nothing, since the files on a recorder HD are less fragmented than your computer. Windows would not recommend defragmenting a recorder HD since there is no problem. Most modern HDs can access files, even if very fragmented, faster than the user needs. You are limited not by fragmentation but transfer speeds, and they are slow on a recorder compared to what goes on with a gaming computer.

Or think of it this way- your computer has literally tens of thousands of files and the HD has no problem keeping up. Your DVR might have 100. No comparison.

Some seem to confuse defragmenting with formatting. A deep format literally erases everything from a drive and leaves 0s (if set up that way). A lesser format only erases the file access portion of the drive and makes the drive look empty, but there are actually lots of files and parts of files still on the drive. That is what happens when you delete the title list on a recorder HD. The drive looks empty, but if you had the proper software, you could recover many of the titles. Which is why the FBI wants that laptop, even if the user thinks they have deleted the incrimination files, or even formatted the drive.

Regarding the 2nd choice. That would be assuming it had that feature. AFAIK, mine doesn't, nor do AVHDDs'.

If you defrag a drive with files on it, you are only joining any separated titles into one file. But that generally will accomplish nothing, since the files on a recorder HD are less fragmented than your computer. Windows would not recommend defragmenting a recorder HD since there is no problem. Most modern HDs can access files, even if very fragmented, faster than the user needs. You are limited not by fragmentation but transfer speeds, and they are slow on a recorder compared to what goes on with a gaming computer.This is true but you are comparing apples to oranges. I don't believe the capabilities/transfer speed of the HDD are the issue with regard to defragging.

Remember the file systems on DVDRs are proprietary. They are not running Windows or Linux, and apparently are much more limited. My Pioneers can only handle up to just 999 recordings on the HDD. Every file fragment takes up pointer space, and I believe many of the HDD problems reported on this forum are a result of allowing the drive to become too full and/or fragmented. This may be due to an insufficient upper limit of pointers available in the file system. I think the defrag feature may be included by manufacturers to help reduce the number of file system pointers as well as to reduce wear & tear on the drive.

Also, keep in mind the file sizes on a DVDR are much larger than most files on a typical computer, and therefore since they take up more space they are more subject to fragmentation, causing more head movement especially during chase-play, FF, REW etc. I think cleaning off the drive periodically (when possible) is the best idea since the defrag feature is hard work for the HDD, and takes a long time too if there's lots of stuff on the drive. Also, defragging is not a good idea if the drive is nearly full because there isn't enough free workspace.

To be clear, since the OP isn't, are we talking about hard drives in computers or stand alone DVRs' (since we are in a "DVD Recorder" forum)??

Are we talking about hard drives in computers or stand alone DVR's?

My Thread/Poll was referring to Stand Alone DVR's.

Suplex,

I voted

"Does deleting all titles off the HDD, act as a defrag?
Yes, your HDD Recorder is as good as defragged now"

But one would think that deleting all titles would actually be better then just defragging the drive because with all the titles deleted and a now "empty" drive to start recording with would be the next best thing to a real format. But just defragging would still have some files on it, and no matter how good it could optimize the free space you probably still have some fragmentation left.

A more interesting question and more important idea, as has been touched upon by other posters is, do you think deleting all files is as good as a format?

My Thread/Poll was referring to Stand Alone DVR's.

Hmmm... I thought you meant DVDRs.

There should be a "defragging very well may be irrelevant".. just like it is on modern computer filesystems.

Hmmm... I thought you meant DVDRs. How do you "defrag" a DVD?? :confused:

If you delete all the titles off the HDD, you may as well format the drive while you're at it. It's very possible there is some leftover crud somewhere from the deletes (Think of when you have to run chkdsk on a Windows PC) and a format would give you a pristine, good as new, HD.

I know DVRs aren't using the same filesystems as Windows but I would think occasional defrags are a good idea, but a complete format once in a while would probably be the best.

I agree with Jim. However, I would think the order of preference would be:
1. Erase all file -- Good,
2. Defrag the HD -- Better,
3. Format the HD -- Best.

However, I have a Toshiba XS-32 and I don't recall ever seeing an option to defrag the HD.

How do you "defrag" a DVD?? :confused:

I said I thought we were talking about DVDRs, i.e. DVD recorders, not DVRs. I don't see how one could "defrag" a DVD, unless possibly with a DVD Ram, which I have no experience with... :D

As I look over the thread, the OP didn't distinguish, it just said "HDDs." Some people replied about DVRs, and some DVDRs, but I thought the OP really meant DVDRs, so I was wrong.


YOW! I just looked at the poll, and now I'm really confused. Since you can't edit on a DVR, I guess Suplex really meant DVDR, not "DVR," as he stated when asked...

I think it is obvious that "DVDRs" refers to DVD recorders in the plural. At least the way DVD recorders in the plural are refereed to in this forum. Not DVD-R discs in the plural. I knew what you meant. DVD-Rs never even crossed my mind.

Since you can't edit on a DVR, I guess Suplex really meant DVDR, not "DVR," as he stated when asked...

What my original intention was (for creating the Thread/Poll) was referring to DVD Recorders (like Panasonic, Philips, Toshiba, Pioneer, etc...) and not Cable Boxes, or Tivo Units that have recording ability.

You're correct about not being able to edit on a "Recording" Cable Box, I am unsure about Tivo though as I have never used one.

Let me ask this. Is a DVD Recorder, by one of the manufacturers I mentioned above, also known as a DVR? My Cable company (Verizon Fios) sent me a Motorolla Cable Box that has recording ability, is that the DVR?

This would mean my Motorolla Cable Box is a DVR, and my Pioneer 640 is a DVD Recorder? I am unclear as to whether or not each unit can be referred to as a "DVR"?

DVR = digital video recorder = cable box with HDD also called PVR (personal video recorder)

DVDR = DVD recorder, with or without HDD

My understanding has always been the following:

DVR - Digital Video Recorder. Meaning what is typically described as a cableco or satellite DVR. No DVD burner.

DVDR - DVD recorder. Meaning what is typically described as a DVD recorder. With DVD recorders there are subsets. Some DVD recorders offer DVR (digital video recorder) features. A DVD recorder with a HDD for example offers DVR functionality.

A DVD recorder with a HDD for example offers DVR functionality.

My Pio 640 with a 160GB HDD doesn't really offer "DVR functionality," although I understand some DVDRs do. I can record something, and use "chase play," but that isn't really the same thing exactly as recording everything, all the time it is turned on, into a buffer.

Many DVD recorders offer DVR functionality. DVR features to many people means the ability to chase play, save recordings to the HDD, play a saved recording while another is being recorded, set timer recordings, offer an on screen guide, etc. Some DVD recorders offer all of these features. Some DVD recorders offer a few of these features.

There are DVD recorders that will begin to buffer when turned on. The Philips 3455 comes to mind. But I'm not sure that is a desirable feature. Others allow the user to engage a buffer at the users discretion.

One difference though with DVD recorders used as a DVR is that DVD recorders only offer one tuner. While most DVRs offer two tuners.

Basic question I have to ask is if you delete all of your recorded content on your HDD (doesn't matter what brand/model you have), is that the equivalent of defragmentating it?Seems like an odd thing to do a poll on. If everyone agrees that deleting all the titles does a defrag, does that make it true? Not necessarily.

I agree with those who say it depends on the file system. And I also agree that defragging or deleting all your titles shouldn't be necessary if the file system is properly designed. Unfortunately we have a lot of anecdotal evidence that suggests some file systems are not well designed.

Fortunately, despite tons of editing on four Pioneer DVD recorders (533,633,and two 640s) over a couple of years, and with my wife never having defragged or deleted all her titles (she's constantly fighting to recover enough space to record new shows) we've never run into any issues. This, coupled with the fact that I've never read any posts here by other Pioneer users which seem like file system corruption issues, leads me to believe that the Pioneer file system is quite robust.

This whole poll seems like a question in search of a problem.

If you delete all files on a drive, you have, in essence, defragged and formatted the drive. There are still lots of left over files still on the drive. But who cares? They will be overwritten as if they did not exist.

Plus, if you defrag, depending on the defrag software, you can still have clumps of files all over the drive, but individually they are not fragmented. So the next file you put on the drive can easily be fragmented if it does not fit in the first space it is directed to. So you are fragmented again.

As far as corrupted files, like checkdisk finds on a computer, my guess is they would cause major problems on a recorder's HD. But even if they did, deleting the parent file effectively removes the corrupted piece since it no longer will be pointed to by the recorder's "FAT" .

It would be nice to have someone point out all the problems we are having with fragmented drives, but I have yet to see a post from anyone who has run into such a problem. Now corrupted files are something else, but a simple delete usually solves that. If not, then delete all files, but that has nothing to do with defrag, since the corrupted file will still be there to cause problems.

As noted, this is a poll in search of a problem.

I have a toshiba xs 32 and the manual says to either delete all the titles or format the HDD occasionally. There is no specific defrag program but the reason given for the deleting or formatting is to defrag. I also believe that if you keep a lot of unused space on the HDD it reduces fragmentation problems

Plus, if you defrag, depending on the defrag software, you can still have clumps of files all over the drive, but individually they are not fragmented.If the software doesn't also consolidate free space then it's a pretty poor excuse for defragmentation, IMHO.

...And I also agree that defragging or deleting all your titles shouldn't be necessary if the file system is properly designed.Sean you and Mattack seem to be in agreement on this, but maybe you'll respond to the question he missed or avoided: I'm curious to know how any well designed file system can manage to keep large files from becoming fragmented without rewriting the entire file after every edit, which is much too slow (even if HDDs had huge expensive buffers, which they don't,) and would waste too much space because the DVDR could only write where there is a big contiguous free block available.

I believe we are all normally living with considerable amounts of fragmentation on our DVDRs, (and computers) but it is masked by faster drives with read-ahead buffers so we don't notice it as much as we used to on older computers...until the drive fails and we blame it on poor HDD design.

It isn't really an issue for day-to-day operation on a DVDR because speed isn't required that much (maybe a bit more during FF and REW,) but if the drive gets too fragmented and left that way, it will reduce the life expectancy guaranteed IMHO. Maybe I'm missing something, but I'm interested in hearing the logic.

I think it depends on the file system used. There are recorders out there that use the windows fat file systems. These would probably need to be defragmented.

But if for example a recorder use a file system similar to ext2 in linux that would be a different story. It is not possible to defragment the ext2 file system. But the file system is so darn efficient (fragmentation can run in the 1-3% range) that a defrag is not necessary. About all you can do with ext2 is delete the partition and start over - but again this is typically not necessary.

So not knowing what type of file system these recorders use makes it a tough guess concerning fragmentation. Defrag may not even be a possibility. Maybe that is why with some you can really only do two things. The first is to delete all content. The second is to format. Perhaps this format does more than what the term typically means. In this case perhaps the partition is deleted and rebuilt as when deleting and creating a partition in ext2.

If they use a file system similar to my cable STB DVR it probably isn't necessary. It has been buffering two tuners 24/7 for over three years now. And every time a channel is changed the buffer gets deleted. That's pretty heavy duty.

edit - after a bit of looking around it looks like there are defrag utilities for ext2. I don't really understand the point. ext2 will typically hover around fragmentation at less than 3% of the partition. If you defrag it it will reduce things but very quickly fragmentation will go back to it's comfort zone (1-3% or so) and then maintain this level of fragmnetation. Unlike fat which just gets worse over time/use.

Sean you and Mattack seem to be in agreement on this, but maybe you'll respond to the question he missed or avoided: I'm curious to know how any well designed file system can manage to keep large files from becoming fragmented without rewriting the entire file after every edit....

Well, I admittedly don't know all of the details, but you don't either.

For example, the Tivo 'filesystem' is really some sort of database. Obviously they can handle at least 3 streams of full HD at a time (2 recording, one playing) + and downloading guide data + TivoToGo (in November).

Again, the people that want defragmenting are thinking too much like a [bad] personal computer. Again, in 25+ years of computer use, I rarely have ever defragmented anything.

There are DVD recorders that will begin to buffer when turned on. The Philips 3455 comes to mind.

Intersting.. Does that mean you can also delete one recording while another recording is happening?

(If not, does that mean it also pauses/skips the buffer when you delete a recording?)

Sean you and Mattack seem to be in agreement on this, but maybe you'll respond to the question he missed or avoided: I'm curious to know how any well designed file system can manage to keep large files from becoming fragmented without rewriting the entire file after every edit, which is much too slow (even if HDDs had huge expensive buffers, which they don't,) and would waste too much space because the DVDR could only write where there is a big contiguous free block available.

First of all, it's important for the file system to properly manage free space. If two titles are deleted which are adjacent to each other on the disk, the file system should recognize that there is one large block of free space as opposed to two adjacent smaller blocks. I recall one post which suggested that the recorder in question (sorry, don't remember which one) used linked lists to manage freespace and it didn't do this kind of consolidation - IIRC this was suggested as a contributing factor to the issues people were having with it.

Secondly (and this isn't directly fragmentation related, but is critical nonetheless) the file system has to be failsafe. If the power dies while the file system is in the middle of updating the file system metadata, it needs to be able to recover correctly. In the computer world, FAT tends to be lousy at this while NTFS is very good. The anecdotal evidence suggests that a simlar reliability differences exist in various DVD-R file systems.

I believe we are all normally living with considerable amounts of fragmentation on our DVDRs, (and computers) but it is masked by faster drives with read-ahead buffers so we don't notice it as much as we used to on older computers...until the drive fails and we blame it on poor HDD design.I completely agree that a DVD-R hard drive gets fragmented like this over time. And perhaps I'm in the minority, but I really don't feel that it's a problem. A DVD recorder is never doing more than two things at a time (recording one show while playing back another) and the rate at which it does it is pretty much fixed. Modern hard drives have no problem keeping up with this level of activity. The same drives used in DVD recorders have to keep up with much higher peak activity levels in an ordinary desktop computer system.

In over 30 years of experience with computer systems I've never seen anything to indicate a strong relationship between hard drive activity and longevity. I've watched super-busy hard drives churn away year after year with nary a complaint, and other drives which sit around doing diddly-squat die after a few months of service. I have seen some relationship between longevity and stop/start cycles / physical handling, but even that's been pretty tenuous. Hard drives just seem to quit when they feel like it, and perhaps my experience is abnormal but all in all I've found them to be pretty darn reliable, all things considered.

Remember that the way hard drives are constructed, the heads don't touch the surface of the disc (except when the drive is powered off), and the high-speed spindle bearings (which aside from shocks and foreign contamination are the high-risk failure point of a disk drive) are always running whether the disc is actively transferring data or not. The disk industry quotes MTBF figures based only on total run time and start/stop cycles (which cause wear because the heads settle onto the disk platters) - head movement is not seen as a significant contributor to failure.

I'm not saying that I actually trust hard drives. I always treat them as if they could fail at any moment - so I fastidiously back up my computer data and I offload anything I want to keep off my DVD recorder promptly. But I don't fret about exessive disk activity causing my hard drive to fail.

Now you may want to take this with a grain of salt since I did have a hard drive failure in my Pioneer 633. But even if it was activity related the culprit was much more likely to be the 24/7 TVGOS churning than any fragmentation issue. And my wife's 533 has never had a problem, despite getting the same TVGOS churning, seeing much heavier record/edit/delete service over significantly longer time, and running with a much fuller hard drive than mine ever did. So go figure. :rolleyes:

First of all, it's important for the file system to properly manage free space. If two titles are deleted which are adjacent to each other on the disk, the file system should recognize that there is one large block of free space as opposed to two adjacent smaller blocks.
I would think that is a bare minimum requirement since it will (unless it's a poorly designed linked-list file system) just happen with no extra effort as a product of removing the file's entry from the used space allocation table upon deletion. (If it isn't removed from the table, then it isn't deleted.) So that's all?

No offense, but when you and Mattack say "defragging or deleting all your titles shouldn't be necessary if the file system is properly designed" it doesn't sound like either one of you really have anything concrete to base the statement on. Sounds like it's mainly convenience through optimism or wishful thinking. Don't get me wrong...I'm not a defragger either, but I do believe fragmentation is more of an issue than most users believe, or are aware of. We just don't detect it because the drives are faster and quieter and speed isn't an issue on DVDRs. We sit far from the unit and are probably oblivious to how hard the drive has to work when we chase play, record and play at the same time and FF, REW etc. (If it was a computer, the HDD activity light would be on solid all the time during recording and playback.) Those are big files that are prone to fragmentation due to editing etc, and can cause a lot of head "thrashing" if the drive isn't cleaned up occasionally.
In over 30 years of experience with computer systems I've never seen anything to indicate a strong relationship between hard drive activity and longevity. I've watched super-busy hard drives churn away year after year with nary a complaint, and other drives which sit around doing diddly-squat die after a few months of service. I have seen some relationship between longevity and stop/start cycles / physical handling, but even that's been pretty tenuous. Hard drives just seem to quit when they feel like it, and perhaps my experience is abnormal but all in all I've found them to be pretty darn reliable, all things considered.Well I'm just a 25 year newbie, :) but to some extent I agree there often doesn't seem to be a significant trend, however I think there are many other factors to consider: According to an industry insider I spoke to, most modern drives are intended for workstations and aren't built to last like the server drives in our experience that just kept chugging away. Also, on servers fragmentation often isn't as common because people rarely delete files compared to workstations where temporary Internet file caching etc takes place. Mostly files just get added to servers and they are rarely edited to become smaller like on DVDRs. Even deletions are typically done in large chunks during archiving by IT folks like you. I don't think the inexpensive workstation drives used in our DVDRs are built to last compared to the drives that just kept chugging away years ago, but maybe usage patterns do contribute more than we realize to drive longevity or premature failure.Remember that the way hard drives are constructed, the heads don't touch the surface of the disc (except when the drive is powered off), and the high-speed spindle bearings (which aside from shocks and foreign contamination are the high-risk failure point of a disk drive) are always running whether the disc is actively transferring data or not. The disk industry quotes MTBF figures based only on total run time and start/stop cycles (which cause wear because the heads settle onto the disk platters) - head movement is not seen as a significant contributor to failure.I believe fragmentation is more likely to contribute to wear on the heads' movement mechanism rather than the bearings or the heads themselves.

BTW: I'm pretty sure we discussed it before, and I don't think the heads rest on the platters at shutdown on modern drives. That's why you hear the wacky little sound from a HDD at shutdown (and you're supposed to wait before moving the unit,) while the heads park away from the platters, suspended on a little post. The heads themselves never touch anything unless there's a crash.
Now you may want to take this with a grain of salt since I did have a hard drive failure in my Pioneer 633. But even if it was activity related the culprit was much more likely to be the 24/7 TVGOS churning than any fragmentation issue. And my wife's 533 has never had a problem, despite getting the same TVGOS churning, seeing much heavier record/edit/delete service over significantly longer time, and running with a much fuller hard drive than mine ever did. So go figure. :rolleyes:Hmmm, perhaps not a grain of salt but a big blue salt lick as used on farms? :p
Sounds like you may agree that the heads thrashing could cause a premature failure. Do you agree excessive fragmentation can cause the heads to "thrash"?

The 533 was last years model...hardly a long history to base your opinion on especially when your 633 did already die, apparently attributed to the "thrashing" of heads...Your wife may remain lucky, but if I were you I would off-load to DVD anything important to you wife now. ;)

I don't sit around fretting about fragmentation either (on my computers or DVDRs) but I do hope my DVDRs will last until quality HD DVDRs are readily available here, and that may be a while. Possibly longer than I expect a PC to last.
From what I've read, there seems to be a trend that HDD DVDRs are often not lasting more than 2 or 3 years, and it wouldn't surprise me if those who allow the HDD to remain mostly full are shortening the life of the unit and over time fragmentation becomes a significant contributor. I just don't think it's responsible to claim there are no ill affects from fragmentation without at least a good theory as to why, when with a little knowledge of storage/file system techniques the opposite would seem logical.

I'm not saying we should all defrag weekly...I never do. But as mentioned I do try to empty the drive during re-run season so fragmentation doesn't get a chance to snowball and shorten the life of the drive. I just think it's good advice and not too anal to do the same when it's convenient if you want the unit to last, and it looks like our neighbors in the US need their HDD DVDRs to last as long as possible. ;)

Here's a slice of the apple from both perspectives. The first is that for technology to be created to address fragmentation it must be considered a problem - somewhere and by somebody. Here's a Hitachi solution for DVRs. It is a linux driven software solution:

http://www.hitachi.us/Apps/hitachicom/content.jsp?page=PressReleases/details/01052007_1.html&path=jsp/hitachi/aboutus/Press-Media/

From the link:

Through “smart” hard drive management, AVSM technology helps reduce duty cycle by up to 60 percent and eliminates disk fragmentation, ultimately helping to extend the life of the hard drive and the host STB system.

Now engadgets take on it:

http://www.engadgethd.com/2007/01/06/hitachi-develops-avsm-software-to-make-dvr-hard-drivers-smarter/

From the link:

Overall, the software reportedly reduces duty cycles "by up to 60 percent" and all but eliminates disc fragmentation, but realistically, with new units popping up entirely more frequently than your average hard drive takes to perish, hooking DVRs up with all these smarts might be a bit unnecessary for those who stay on the bleeding edge.

I'm not sure is there ever will be a definitive answer. I land on the side of a bit of caution. I use playlists for editing and will free up content on a HDD if I think it is time.

No offense, but when you and Mattack say "defragging or deleting all your titles shouldn't be necessary if the file system is properly designed" it doesn't sound like either one of you really have anything concrete to base the statement on.Although it may not have been totally obvious, I made that statement in the context of avoiding software corruption. In my definition a "properly designed file system" (which includes the software which manages it) will never corrupt the data. That's a fair position, I think.

In all the years I've managed systems, I've never heard anyone in the industry recommend defragmentation in order to increase disk life. Even the manufacturers of defragmentation software don't make this claim, and they usually go a little overboard in stating benefits. Defragmentation is always recommended in order to improve performance. Since DVD recorders don't place enough demands on even badly fragmented hard drives to affect performance, my opinion is that defragmentation is not necessary. But it's just my opinion, based on my experience.

According to an industry insider I spoke to, most modern drives are intended for workstations and aren't built to last like the server drives in our experience that just kept chugging away. Also, on servers fragmentation often isn't as common because people rarely delete files compared to workstations where temporary Internet file caching etc takes place.My group supported several hundred desktop workstations that used commodity drives as well as the high-end stuff in the server room. And, interestingly, this paper from the 5th USENIX conference (http://www.usenix.org/events/fast07/tech/schroeder/schroeder_html/index.html) suggests that desktop SATA drives are no less reliable than the SCSI or FC drives used in most datacentres. What the datacentre drives DO have is better ECC codes and better firmware to monitor/report correctable errors, all of which is combined with server software to track and report them - this allows managers to swap degrading drives out before they become an issue. And of course RAID is used so that data is preserved even if a drive does fail.

I believe fragmentation is more likely to contribute to wear on the heads' movement mechanism rather than the bearings or the heads themselves.Yes, of course this is true. My point was that it's not very significant compared to the spindle bearing wear that's happening all the time. I suppose you could devise some exercise software which would issue full-stroke seeks to the head at the maximum rate continuously in order to increase the wear on the head actuator bearing to something approaching that of the spindle bearing, but it's an extreme case. Even a badly fragmented DVD recorder isn't going to be doing nearly that much seeking. DVD recorders just don't do enough things at once and don't have the continuous read/write throughput that would drive the disk that hard, IMO.

I'm pretty sure we discussed it before, and I don't think the heads rest on the platters at shutdown on modern drives. That's why you hear the wacky little sound from a HDD at shutdown (and you're supposed to wait before moving the unit,) while the heads park away from the platters, suspended on a little post.Some Hitachi drives have the plastic ramps that allow the drive to move the head actuator beyond the rim of the disk when it's spun down (here's a PDF that describes it) (http://www.hitachigst.com/tech/techlib.nsf/techdocs/9076679E3EE4003E86256FAB005825FB/$file/LoadUnload_white_paper_FINAL.pdf), but most drives just move the heads to a "parking" track (usually the innermost track) which isn't used to store data (see this Wikipedia article (http://en.wikipedia.org/wiki/Hard_disk)). The sound you hear is the heads seeking to the parking track and an elecromagnet engaging a locking pin to keep them there. This is why the manufacturers include the number of start/stop cycles in their MTTF specifications. Again I'll note that these specifications are based on run time and start/stop cycles only, the manufacturers do not consider seek activity important enough to list as a factor when they quote the lifetime of a drive.

Sounds like you may agree that the heads thrashing could cause a premature failure. Do you agree excessive fragmentation can cause the heads to "thrash"?I agree that head movement causes some wear, I just don't believe it's that significant compared to the other causes of hard drive failure. And I believe that the amount of head movement you get in a DVD recorder is pretty mild compared to a typical desktop computer system.

The 533 was last years model...hardly a long history to base your opinion on especially when your 633 did already die, apparently attributed to the "thrashing" of heads...My point was that her machine saw a lot heaver use than mine over a longer period of time and yet it was mine that died. This is a data point (albiet only one out of milliions) against the notion that lots of seek activity shortens the life of the drive.

I do try to empty the drive during re-run season so fragmentation doesn't get a chance to snowball and shorten the life of the drive. I just think it's good advice and not too anal to do the same when it's convenient if you want the unit to last, and it looks like our neighbors in the US need their HDD DVDRs to last as long as possible. ;)There's certainly nothing wrong in doing that. It can't possibly hurt, and maybe it really does have a benefit. But my own personal belief is that any benefit is going to be pretty insignificant, so I don't bother with it myself.

Here's a Hitachi solution for DVRs. It is a linux driven software solution:

http://www.hitachi.us/Apps/hitachicom/content.jsp?page=PressReleases/details/01052007_1.html&path=jsp/hitachi/aboutus/Press-Media/
What I found particularly interesting was this:
The ability to manage up to 14 HDTV (19.3Mb/s) streams from one 3.5-inch HDD

That's a huge, huge jump in throughput from what a one-tuner DVD recorder has to handle. It's well over 10X as much (almost 30MB/sec compared to about 2MB/sec). To provide this kind of performance from different streams and not have stuttering due to seeks they really have get the maximum efficiency out of the drive. Allowing the drive to fragment simply wouldn't be an option.

http://www.hitachi.us/Apps/hitachicom/content.jsp?page=PressReleases/details/01052007_1.html&path=jsp/hitachi/aboutus/Press-Media/

Now engadgets take on it:

http://www.engadgethd.com/2007/01/06/hitachi-develops-avsm-software-to-make-dvr-hard-drivers-smarter/

I'm not sure is there ever will be a definitive answer. I land on the side of a bit of caution. I use playlists for editing and will free up content on a HDD if I think it is time.Interesting find. Seems developers at Hitachi (the best workstation HDD maker IMHO) who presumably know something about storage think fragmentation could present problems even on a DVR, most of which don't offer editing capabilities.

The author of the engadgethd article may be right about the general public, but the DVR manufacturer decision makers may decide to err on the side of caution and be sold on using Hitachi drives since their customers buy in bulk and rent the units for indefinite periods.

In all the years I've managed systems, I've never heard anyone in the industry recommend defragmentation in order to increase disk life. Even the manufacturers of defragmentation software don't make this claim, and they usually go a little overboard in stating benefits. Defragmentation is always recommended in order to improve performance. Since DVD recorders don't place enough demands on even badly fragmented hard drives to affect performance, my opinion is that defragmentation is not necessary. But it's just my opinion, based on my experience.Fair enough, and thanks for the sincere responses. Again, I'm not recommending defragging either, and I'm not trying to suggest fragmentation is an issue with regard to performance. I just wonder how much it affects drive reliability. There seems to be a significant trend in the number of HDD DVDR users reporting drive problems when their drive was too full, and not just file system errors but failure of the drive itself. Not just one make either. Nearly full drives seems to be something to avoid and I doubt it is a file system bug overlooked by all the manufacturers.

My group supported several hundred desktop workstations that used commodity drives as well as the high-end stuff in the server room. And, interestingly, this paper from the 5th USENIX conference (http://www.usenix.org/events/fast07/tech/schroeder/schroeder_html/index.html) suggests that desktop SATA drives are no less reliable than the SCSI or FC drives used in most datacentres.Do any current HDD DVDRs use SATA? I thought they were all PATA. Regardless, I guess they will soon. Seagate recently announced they will soon stop making PATA drives...others will probably follow suit.

DVD recorders just don't do enough things at once and don't have the continuous read/write throughput that would drive the disk that hard, IMO...I agree that head movement causes some wear, I just don't believe it's that significant compared to the other causes of hard drive failure....And I believe that the amount of head movement you get in a DVD recorder is pretty mild compared to a typical desktop computer system.
Apparently you're not a "Power Viewer". ;)

Again, I agree except that I believe if the drive on a DVDR is allowed to become very badly fragmented (which is likely if you edit a lot and keep the drive fairly full without ever clearing it off,) during typical usage head movement could easily exceed that of a typical desktop computer, especially when doing simultaneous play/record etc. That's a lot of data pumping continuously and it may be very little movement for a drive that is not fragmented, but not so otherwise.

Anyway, I've had enough of this fraggin topic. I've fragged it to death. Frag it.

There seems to be a significant trend in the number of HDD DVDR users reporting drive problems when their drive was too full, and not just file system errors but failure of the drive itself.Perhaps I'm cynical, but I suspect that's more a reflection of how many people let their drives fill up as opposed to a correlation between space used and reliability. In other words, if 80% of the DVD recorders have drives that are always nearly full (my wife would definitely fit into this category), then you'd expect about 80% of drive failues to occur with nearly full drives. It would be interesting to find out how full DVDR drives are, on average.

FWIW, my drive failure occurred with the drive pretty much empty (there were only 1 or 2 titles on it, if I recall correctly).

Do any current HDD DVDRs use SATA? I thought they were all PATA.Not yet, as far as I know. But SATA drives are targeted for the desktop market just as PATA drives are, and there really aren't any mechanical differences between them, so one would expect the reliability of SATA drives to be similar to that of PATA.

I agree except that I believe if the drive on a DVDR is allowed to become very badly fragmented (which is likely if you edit a lot and keep the drive fairly full without ever clearing it off,) during typical usage head movement could easily exceed that of a typical desktop computer, especially when doing simultaneous play/record etc.I wrote a some lengthy paragraphs comparing metrics measured on my own computer running a virus scan to the activity levels a DVD recorder would see if it had to dealing with two XP-quality streams simultaneously, but I'll spare you. Suffice it to say that I'm still convinced that PC hard drives are more fragmented and get beat up more than DVD recorder drives. And since I've never heard of anyone defragging their PC HDD in order to extend it's life, it seems (to me) sort of silly to worry about it for (what I see as) a less-stressed DVD recorder.

I'm not trying to discourage anyone from running defrags - as long as the software is sound then it shouldn't cause any harm and it certainly has the potential to do some good. Each person has to decide for themselves what they're comfortable with, and whether my own "if it ain't broke, don't fix it" guideline is a sound strategy. All I'm trying to do here is to explain why I think the way I do.

And you're absolutely right - I'm a "Power" PC user but not a "Power Viewer". Maybe this helps to explain my cavalier attitude. ;)

Frag it.:D Indeed!