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What happens to deleted space?

post #1 of 15
Thread Starter 
When you delete a title that's in between other titles, what happens to the space left by the deletion? Does it leave the blank space there taking up HD or DVD recording space?

It would be nice to believe that when deleting a title, somehow the other programs are temporarily placed in a buffer, then re-arranged on the HDD/DVD so there is no gap (empty space) from the deleted title. You would then have continuous recordings with all the empty space at the END of the last recording.

P.S. I don't believe this is what actually happens but it would be nice if this did happen.
post #2 of 15
On RAM discs and for hdd based recorders, deleted segments are completely erased-the blank space is left in their place. When a new recording is started, it is placed in the first available area on the drive or RAM disc, not after the last recorded show.
With hdd models, it's best to avoid deleting segments and leaving spaces left within them. Many feel that it makes the hdd work that much harder when fast forwarding/rewinding, and can lead to drive problems. So editing out commercials, then dub to disc, and erase the remaining program.
post #3 of 15
Just keep in mind that whenever you delete any recording, you are creating gaps on the hard drive.
post #4 of 15
Also a good reason to offload everything from the HDD regularly so it can start writing "at the beginning" again and in sequential order. The Pio 53s/63x series and 640 have an automatic "Optimize HDD" feature (notifies you when needed) that closes the gaps, like "defrag" on a std computer HDD, so you never have to offload those Pio HDDs "manually."
post #5 of 15
When you delete a title on a DVDR, it is erased from the index, but the space cannot be recovered of course, because the disc is write-once.

When you delete a title on DVDRW, it is possible to re-use the space, but there is a problem. DVD recorders do not generally support automatically splitting a recording in progress between two physically separated files on the disc, so any new recording would have to fit within the available erased space. If it does not fit, it will carry on overwriting the following recording. For that reason, DVD recorders which support this option have a setting that says whether you want them to re-use erased space or not, and it's up to you to be careful.

On HDD, it's not a problem. The HDD has a standard random-allocation filing system that easily deals with non-contiguous space. You can erase and re-use as much as you like, and it's generally unnecessary to worry about fragmentation.
post #6 of 15
DVD-Ram is random allocation/access as well and performs much like a HDD.
post #7 of 15
Quote:
Originally Posted by amesdp View Post

On HDD, it's not a problem. The HDD has a standard random-allocation filing system that easily deals with non-contiguous space. You can erase and re-use as much as you like, and it's generally unnecessary to worry about fragmentation.

I tend to be more concerned about fragmentation because although it may not noticeably slow your DVDR like it would to a computer, it will indeed still cause the HDD to work harder and probably shorten its life. The reports I have read of HDD failures seem to most often come from users who either didn't worry about fragmentation, allowed the HDD to get too full, or both. The file systems are proprietary so I don't know exactly how they all work, but the more fragmented the HDD, the more complex the directory (file allocation table, linked list or whatever) is, and there must be limits to the pointer capacity.

If fragmentation weren't an issue, I suspect manufacturers like Pioneer wouldn't bother to include a defrag/optimization feature.

My rule of thumb for my Pioneer DVDRs:
1) Avoid filling the HDD up too much.
2) Like Westly-C I only edit out commercials immediately before off-loading to DVD.
3) Once a year (usually during rerun season,) clear off the DVD by off-loading anything I want to keep to DVD. (If I plan to later return it to the HDD, I use a VR mode DVD so I can high-speed copy back to HDD with no pq loss.) Clearing the HDD is less hard on the HDD than a defrag which causes the HDD to work very hard possibly for hours if there is lots on the HDD. I'm also less likely to lose valued recordings this way if I do have a HDD failure because everything I want to keep gets backed up to DVD.

Obviously there are occasional exceptions regarding #2, but I insist on 1 and 3 and no problems so far.
post #8 of 15
Quote:
Originally Posted by amesdp View Post

On HDD, it's not a problem. The HDD has a standard random-allocation filing system that easily deals with non-contiguous space. You can erase and re-use as much as you like, and it's generally unnecessary to worry about fragmentation.

I'd agree with this, but with the caveat that there have been reports of issues here that suggest some models have poorly implemented file systems which cause problems if the HDD gets too fragmented. This has not been a problem with my Pioneer recorders, on which I've performed heavy HDD editing of shows for well over a year with no ill effects whatsoever. But I do keep my hard drive fairly clean and it's rarely more than 50% full.
post #9 of 15
Quote:
Originally Posted by Sean Nelson View Post

This has not been a problem with my Pioneer recorders, on which I've performed heavy HDD editing of shows for well over a year with no ill effects whatsoever. But I do keep my hard drive fairly clean and it's rarely more than 50% full.

Sean if my memory serves correctly, you had a HDD fail on your 633 right? Is it safe to assume you attribute that solely to the poor TVGOS implementation? I just wonder if your somewhat lenient position on fragmentation could perhaps have been a contributing factor?

I also recall you did mention previously you try to keep the drive under 50% so an over-full drive probably wasn't the culprit. Aren't you on cable and had the TVGOS working most of the time? (So the 633's HDD wasn't thrashing all night like some others?)

I'm don't mean to be argumentative, (I am also a fan of the reliable Pioneer file system,) but I'm curious to know why you discount fragmentation as a possible contributing factor to the failure of your 633's HDD?
post #10 of 15
Quote:
Originally Posted by ACPewty View Post

I'm don't mean to be argumentative, (I am also a fan of the reliable Pioneer file system,) but I'm curious to know why you discount fragmentation as a possible contributing factor to the failure of your 633's HDD?

I do believe that, if "wearing out the drive" is the cause of my hard drive failure, then TVGOS is to blame, not any fragmentation of the titles on the drive. I say this because the TVGOS caused the drive to be thrashing for about 20 hours every day, while my actual recording, watching and copying use of the drive proabably couldn't account for more than 4 hours a day. And the amount of thrashing due to fragmentation couldn't be anywhere near what TVGOS was inflicting on the drive, based on the fact that I could detect no difference in the amount of noise coming out of the hard drive when I was or wasn't playing titles. Based on that, I'd give a wild guess that the fragmentation couldn't possibly have accounted for more than 10% of the activity on the drive. If that's true, and if it really was "wear" that caused the drive failure, then it could have gone for about 15 years without the TVGOS.

As a matter of interest, my wife has a 533 which also runs TVGOS, and she crams her hard drive almost full, does lots of editing, and has had her machine longer than mine with no sign of a hard drive failure. So I'm very skeptical that the "wear" was a direct cause of my failure, I think it was probably just one of those things.

My personal opinion is that in the history of hard drive DVD recorders, fragmentation-related problems have been caused way more often by buggy firmware (often exacerbated by poor recovery from power failures) than by inflicting wear on the hard drive.
post #11 of 15
Ouch on the TVGOS experience. I never realized it was that bad with Pioneer.

The HDDs in my Toshibas don't even blip as a result of TVGOS. I've got one XS55 set up with an external HDD setup and when I change HDDs all of the TVGOS info remains in the machine. Everything - even scheduled recordings. Regardless of the HDD installed. The only thing that changes is the list of recorded material listed in TVGOS based on which HDD is installed. So the HDD is never churning away as a result of any back round TVGOS activity with Toshiba.

I personally think a lot of these HDD failures may be the result of how the DVD recorder is used. A recorded that is used heavily as a DVR I think tends to stress the HDD more. And may add to fragmentation problems.

But then again I have a SA8300HD DVR from the cable company that has two tuners and it grinds away 24/7 buffering both tuners. For years now.

Also editing may play into it. I always use playlists for editing. I know this is recommended in the Toshiba manual and playlists are designed to reduce fragmentation.
post #12 of 15
I think you'll find that the file systems on these recorders are not proprietary. Nobody wants to re-invent the wheel on such a basic software component. They're probably using an MSDOS clone, Linux, or WinCE. The early versions of DOS benefited from defragmenting because of the sloppy amateur design of their disk space allocation routines, but a few simple changes fixed most of the problems, and routine defragging hasn't really been necessary for many years now. I have no concerns about HDD fragmentation in my video recorder causing drive wear and premature failure.
post #13 of 15
Quote:
Originally Posted by Sean Nelson View Post

I do believe that, if "wearing out the drive" is the cause of my hard drive failure, then TVGOS is to blame, not any fragmentation of the titles on the drive. I say this because the TVGOS caused the drive to be thrashing for about 20 hours every day, while my actual recording, watching and copying use of the drive proabably couldn't account for more than 4 hours a day...

Ah, now I see. Since I use satellite and don't really get much OTA signals, my 633 never got a chance to load any TVGOS data so I figured that was why the thrashing never stopped without using the Eureka method to disable the EPG. I assumed if data was received the thrashing would stop and that would have been the case for most users on cable where data was usually available.

I would probably come to the same conclusion as you under those circumstances, although frankly I wouldn't have wanted to allow a malfunctioning unit to operate like that for very long.
post #14 of 15
Quote:
Originally Posted by amesdp View Post

I think you'll find that the file systems on these recorders are not proprietary. Nobody wants to re-invent the wheel on such a basic software component. They're probably using an MSDOS clone, Linux, or WinCE. The early versions of DOS benefited from defragmenting because of the sloppy amateur design of their disk space allocation routines, but a few simple changes fixed most of the problems, and routine defragging hasn't really been necessary for many years now. I have no concerns about HDD fragmentation in my video recorder causing drive wear and premature failure.

I have read a number of reports from users who have tried to access the HDD from their DVDRs using Windows, Linux etc and AFIAK no one has reported success. Everyone seems to agree the file systems are all proprietary, possibly a prerequisite/licensing requirement due to pressure from those concerned about copy protection. The closest anyone has come is to make a bit-for-bit image of a partition, which is actually not very close at all.

AFIAK any drive (DVDR or computer) is vulnerable to fragmentation regardless of the O/S. The only way to completely avoid fragmentation is to only allow contiguous file writes which would waste huge amounts of disk space. I think fragmentation is less noticeable now (on computers) because hardware is faster and buffers are bigger, and indeed some improvements may have made a difference but considering DVDRs do have proprietary file systems I wouldn't make too many assumptions or take anything for granted if I were you...especially if you know anything about the earlier Panasonic (and Toshiba?) file system that forced users to regularly "format" their HDD, (losing all recordings in the process) just to avoid major problems.

The way I see it, since Pioneer seems to have one of the most reliable file systems and they went to the effort to include a defrag feature, (and prompt users to defrag when some fragmentation threshold is reached,) it's probably not something to be ignored if you hope to have your unit operate trouble-free for as long as possible.
post #15 of 15
Quote:
Originally Posted by amesdp View Post

I think you'll find that the file systems on these recorders are not proprietary.

Similarly to the other reply. Heck, I'd pay money for info about how to get recordings off of an XS32 drive.. i.e. especially info about reading the directory info past when it thinks a drive is 'corrupted'.
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