HDD OPERATING AND MAINTENANCE TIPS
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How Our HDD Operates
Regaining Space on Your HDD
HDD Self-Check and Initialization/Formatting Procedure
Some Tips on Maintaining Your HDD
Repair Utility
Reliability & Longevity of Our HDD
General Info on HDD Longevity
Optimum Use of HDD for Enhanced Longevity?
How Our HDD Operates
The Hard Disk Drive (HDD) in this DVDR and others is like the one in your computer, except it doesn't have a robust operating system like Windows. Our HDDs just have to record streams of video and audio ("User Data") and place them in files and folders for later playing and dubbing... pretty simple stuff.
Just like a computer, a DVDR's HDD stores "pointers" to the User Data (your recordings)... the locations of the actual User Data and the order in which it should be "addressed" for playback or dubbing. That pointer info is in the title/index pic we see in our Title Menu. When we delete a title, the only thing deleted is the location and address info. Without that info, the User Data no longer exists as far as the op. system (OS) is concerned... it now has "permission" to overwrite those file spaces.
Edit instructions are written as we select Start and End points, Divide a title, select an index pic, etc.
To "prove" to yourself that your DVDR is NOT physically
deleting the actual User Data, next time you delete a title, notice how FAST it happens... doesn't matter how long the title is, 2-hrs or 12-hrs, it's "deleted" in the blink of an eye. . and your DVDR OS is SLOW compared to a computer. The DVDR doesn't overwrite it or otherwise do ANYTHING to the User Data except delete the pointer/addressing info.
As a HDD gets full and files are added, deleted and, especially, EDITED, it becomes "fragmented," which means files have been broken into chunks and stored in available empty spaces amongst the multimillion sectors on the HDD. But the robust computer HDD can keep track of all those fragments and assemble them rather quickly when you ask it to... it has a central processing unit (CPU) that operates extremely fast, and it has lots of random-access memory (RAM) and a large cache for temporary storage. But even a robust computer uses the HDD for temporary storage when/if needed.
Our more-simplistic DVDR operating system can also handle fragmented files, especially if all you do is record the typical shows on TV, then watch and delete. You'll be filling and reopening large, contiguous chunks of space on the HDD for more recordings.
You can FILL the HDD with recorded titles as long as you don't start EDITING them. For an ongoing test, I regularly let my refurb'd 3575 fill completely up with a 2-hr M-F timer recording but did no editing. No adverse consequences at all... it just stops recording at the instant the HDD fills up! I delete all the titles at once with the HDD Menu > Delete All Titles command, then start over.
Editing, however, creates lots of ADDITIONAL info to keep track of, like "Delete Title X, Sector X, Fragment X, 01:28:15:24 to 01:31:25:03" (hr:mm:ss:frame), and that data has to be stored until the title is deleted. Again, not a problem if the User Data it applies to is not all over the place, spread amongst many HDD sector, on a too-full, fragmented HDD.
But what happens if many or all of your edits apply to small fragments of User Data all over the HDD? Like a Delete command that applies to the end of Fragment A Sector A and beginning of Fragment B Sector Y. Each start and stop time for each fragment has to be stored until that title is deleted, so two edit instruction for one single Delete. Or a Divide that splits umpteen fragments into two individual titles with multiple Delete instructions that now have to be re-correlated to those new individual title(s).... you get the picture... lots to keep track of!
Lots of detail left out here, and lots of actual "unknowns" so assumptions have been made. Just trying to keep it simple.
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Regaining Space on Your HDD
These DVDRs don't have a "defrag" or "optimize" option, so
you'll have to serve as the "optimizer" using several methods listed below.
Offload HDD Title "Keepers" to DVD
For those titles you want to keep in your archive, offload them to DVDs, then Delete the HDD titles. To offload to DVDs most "efficiently" while maintaining daily usability, use either the Last-in First-Out (LIFO) or First-In-First-Out (FIFO) method of offloading. The point is to Delete full titles at either end of the sequential User Data on the HDD instead of creating "holes" midstream and creating more work for the OS.
Use "Title Delete" or "Delete All Titles" Command
If you highlight a title and press OK, that brings up a Delete Multiple Titles option which can be used to delete multiple titles you select,
as described here. There's also a "Delete All Titles" command in the Setup > HDD Menu for deleting ALL titles in one shot... also great for deleting a "frozen" title that resists normal Title Delete,
as described here.
HDD Format or Factory Check
Two more-drastic methods are
SKIP 079 - Format and
SKIP 013 - HDD Factory Check , both of which end up with a "clean" HDD, with no more title pointers so, duh!, you'll lose all recorded titles in one op..
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HDD Self-Check and Initialization/Formatting Procedure
See this help file for info and procedures for self-checking HDD/DVD cable connections, removing/replacing the HDD and DVD burner, and Initializing/Formatting the original HDD or its replacement (which could be a HDD up to 500GB capacity).
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Some Tips on Maintaining Your HDD
In the end, it's in your best interests to maintain adequate empty space on your HDD, especially before doing complex editing. Some personal tips are:
- For titles you just want to watch, delete them ASAP after viewing.
- For titles you want to keep permanently, dub them to DVD disc ASAP and delete them from the HDD. If needed later, you can always dub them back to the HDD for editing or whatever. The PQ degradation from a real-time dub ON THIS DVDR (Philips-developed codec) is not as bad as you've heard on other DVDRs, esp. if working with a program from a digital channel.
- Don't try to make complex edits (Divides and Deletes) if your HDD is over 95% full. That's an arbitrary, untested number... just use good judgement! Unlike some other DVDRs, these DVDRs don't freeze up when they get totally full, they just stop recording video or editing instructions, but better to be safe than sorry.
- If you encounter a problem on an HDD that's "too full" and want to gain more space, never EDIT stuff out cuz that just adds more complex instructions for the HDD and cache to store and track. DELETE OR DUB TITLES TO DVD IN LIFO OR FIFO ORDER, NOT TITLES IN THE MIDDLE!
- To eliminate the need for Dividing back-to-back shows on the same channel, set individual timer rec programs back-to-back rather than all in one block of time. This gives you separate titles on the HDD. This DVDR is excellent at transitioning between timer programs, losing only 3-sec. of succeeding titles after the first one on analog channels, 5-7 sec if a digital channel is involved. Same for back-to-back programs on different channels.
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Repair Utility
There's a Repair Utility that the
machine can invoke automatically if there is a HDD problem, like power failure during recording.
"Repairing appears on the TV screen and, as explained in the manual:
- If there is a power failure or unplugging during recording, finalizing, formatting or editing (even after Repairing disappears), a repairing process will begin automatically just after turning the unit on again. It may take several minutes up to about several hours.
Our HDDs can repair themselves as you use them. My refurb'd 3575 has a "bad" HDD... slow to start up, noisy, freezes on playback of frist three titles, won't Initialize with Skip 079, fails Skip 013, etc. I've been letting it fill up with titles then deleting them all at once, and now it plays first three titles and Initializes normally!
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Reliability & Longevity of Our HDD
The spec sheets for our HDDs show that they're "designed for 24/7 operation." For example, the Hitachi drives used in the 2160 have a spec called "Availability[4] (hrs/day x days/wk)" and a value of "24x7."
The footnote [4] says this about the 24x7 value:
"Intended for low duty cycle, non mission-critical applications in PC, nearline, and consumer electronics environments, which may vary from application to application."
I think our normal use of these drives is considered "
EXTREMELY low duty cycle" compared to PC usage, considering the highest-stress recording function operates at a max. of 11 Mbps (HQ rec mode), compared to the drive's max. Media Transfer Rate of 1138 Mbps!
Our HDDs also spin on either a non-contact air bearing or, in the case of the Hitachi, a "fluid bearing"... high-viscosity synthetic oil between the sleeve and stator so "there is more conforming surface contact through the lubricant as compared to a Ball Bearing design. Additionally, the lubricant film provides additional damping to shock."
The low duty cycle and fluid bearing, combined with the fact that the mfgr's rated longevity is measured in start/stop cycles, not spin time, should give people at least a reduced concern over autostart rec and leaving the machine on for relatively long periods of time.
Don't forget that setting the Source to L3 (DV) STOPS autorecording for as long as the machine's on that line input (if you're concerned at all)!
Also, several long, continuous recording tests have proved these DVDRs don't get hot.
YMMV of course!?
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General Info on HDD Longevity
Drive mfgrs used to rate their HDD reliability in hours (MTBF) but changed to "start/stop" or "load/unload" cycles as they found it was a more appropriate measure of reliability.
A start/stop cycle is defined here as a power-on/power-off cycle... 50,000 is the norm. Note that the linked article mentions the ongoing "controversy" over always-spinning vs. start/stop aficionados and says we "shouldn't sweat" the small stuff.
Hitachi uses "load/unload" cycles with 300,000 being the norm, a "better" design used first by IBM for their HDDs using load/unload ramps. (Hitachi bought the IBM HDD division in 2003, and WD bought Hitachi's HDD ops in 2012.).
A Hitachi article describes the load/unload mechanics.
In the REAL world, experts say 3-5 years is a good lifespan for a modern HDD in a typical computer environment (hard work),
as described here. Those just happen to be the std warranty period for HDDs... as of Jan 1 2009, Seagate lowered their std warranty period from 5 years to 3 years for our 3575/3576 HDD, and the same as the Hitachi 2160 HDD. Other mfgrs soon followed suit.
"Bit Flux" (or "Fade")
Following are links to two articles that describe info collected from HDD engineers at major mfgrs, which mention "bit flux" (rather than the familiar "disc fade") as a potential problem on HDDs stored without reading for long periods of time. These articles suggest a complete read as being a prudent investment in data longevity on a stored HDD:
Hard Disk Warning! by Larry Jordan.
Technique: Refreshing Hard Disk Storage, by Larry Jordan
The latter article is for apps with computer op systems but still helpful for its suggestion that just reading a drive helps it maintain data integrity. A simple, overnight checksum does the job.
One AVS user who uses the regular checksum method is Sean Nelson.
Here's what he does to maintain data integrity on HDDs used for long-term storage.
Here's some additional info on HDD longevity by SteelTownGuy.
There are many other anectodal user posts on "actual" HDD longevity, incl. one "contrarian" who stored HDDs with data on them in a drawer for up to 10 years and they read fine? Many posts and tech. articles talk about the electronics being the most susceptible to "going bad" over a long time. The HDD/DVD electronics for this DVDR are in the smaller PCB board between the HDD and DVD burner (above the main board).
Update 8/2/11 - The latest HDDs, like the WD AV-GP series in the 515, have a feature called Preemptive Wear Leveling (PWL) that sweeps the drive arm frequently across the disk to reduce uneven wear on the drive surface common to audio video streaming applications. This might just be the ticket to preventing bit fade?
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Optimum Use of HDD for Enhanced Longevity?
For people who might be concerned about using the *same* portion of their HDD by watching-and-deleting, there's been some expert discussion of "bit fade" on HDDs not used for long periods, and some questions being asked in other forums on the effects of recording over the same space repeatedly. So, other people are concerned as well.
Those experts say that reading an entire HDD once per year or every two years will prevent bit fade. Of course, then someone starts talking about having HDDs in a drawer for 10 years and they work right away when reinstalled
in their computer. So, needless to say, this is one of those subjects that can stir up needless controversy.
We don't have a CHKDSK or other computer-like utility
that we can invoke to read an entire disc w/o losing access to recorded titles. The best we can do is fill the HDD up with recordings to make sure we've "used" every bit.
To see if there are any adverse effects of this, I've been letting the HDD in my refurb'd 3575 with a "bad" HDD fill up with recorded titles and, when the HDD fills up,
it just stops recording and won't record any more. This 3575 was always slow to start up, noisy, froze on playback of first three titles, wouldn't Initialize with Skip 079, failed Skip 013, etc.
After several fill-ups, it now plays the first three titles and Initializes normally, so I think filling-er-up once in awhile is a good thing all around!
DanHuff tried my "fill-er-up" procedure to fix his "problematic" HDD.
IMO, some people
who don't do a lot of editing will benefit from letting their HDD get full
yearly or every other year to keep all the bits active. You can do this slowly or quickly, as follows.
Slowly, During Normal Recording Season: Record your normal shows at 1-hr-HQ rec mode. Change all your timer rec programs to HQ and record as many shows as possible, watching oldest shows first (as usual) and Protecting them after watching to identify them as "watched" (with the lock icon), then Unprotecting and Deleting them at an appropriate time.
Quickly, During Summer Doldrums: Set one or more 12-hour timers (11:59:59) at HQ rec mode and fill up all remaining free space on your HDD with "anything" in the summer, then delete them all at once with one command. You can run these 12-hour sessions at night, while you're asleep! Even with a completely empty HDD, the number of "12-hour" titles needed at HQ to sufficiently "fill" a disk would be approx. (subtract existing title lengths from these):
| GB | #12-hr Titles | Plus |
| 160 | 2 | 9 hrs |
| 320 | 5 | 0 hrs |
| 500 | 8 |
4 hrs |
| 1000 | 17 | 4 hrs |
Either way, after you fill a disc, use either the Title List > Delete Multiple Titles command or the HDD Menu > Delete All Titles command, depending on whether you must preserve any titles or not.
Remember, this is only a once-a-year or every 2-year PITA, and it can be done in the summer, not during prime season!
If you do a lot of editing, you prob. already know that keeping some "head-room" is essential to prevent problems caused by a too-full disc with lots of edit instructions and fragments throughout the HDD. Those people will prob. have to keep doing what they're doing now, or record till disc-full at some convenient time once a year or every two years....
Or you can go with the guy who said all this was a crock... he pulled 10-year-old HDDs out of a drawer and they worked fine, in his computer, and hope it works the same in your DVDR
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