lZr
L&M
If you want to read/rewrite the HD, do Defragment in Windows. For iMac there must be special utility about
SteveBennett
Steve Bennett
I think that respooling of tapes is done for a different reason - the tape material gets "sticky" and you have problems with the tape not wanting to wind or being damaged by the winding process. Respooling assures that you can in fact move the tape and that the tension on the tape remains fairly constant. I'm not sure about the need to rewrite (or creat new tapes) periodically. I just haven't read up enough on this.
I personally haven't used tapes in recent years. I don't know if the same problems still exist. With the drop in hard drive prices and increases in capacity, I sold ff my tape drives several years ago... too painful and slow and noisy for my home. I now use multiple hard drives with DVD archive (CDs have been "too small' for me for quite some time).
Defragmenting a hard drive does not guarantee that every file is read and rewritten. Only those files that the defragmenter determines are not optimal may be moved. In fact, a smart defragmenter may move only a portion of a file rather then the whole thing. I don't know the specifics of the Windows defragment tool, but generally speaking, this isn't a reliable "refresh' mechanism.
--Steve
Pixmonix Negative Scanning and Slide Scanning Service
I personally haven't used tapes in recent years. I don't know if the same problems still exist. With the drop in hard drive prices and increases in capacity, I sold ff my tape drives several years ago... too painful and slow and noisy for my home. I now use multiple hard drives with DVD archive (CDs have been "too small' for me for quite some time).
Defragmenting a hard drive does not guarantee that every file is read and rewritten. Only those files that the defragmenter determines are not optimal may be moved. In fact, a smart defragmenter may move only a portion of a file rather then the whole thing. I don't know the specifics of the Windows defragment tool, but generally speaking, this isn't a reliable "refresh' mechanism.
--Steve
Pixmonix Negative Scanning and Slide Scanning Service
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willie_901
Veteran
Corporations avoid possible trouble from read/rewrite issues by doing both incremental back ups on a daily basis along with full back ups on a weekly basis. Usually the full back ups were to tape.
I only back up to an external HD because my color negatives are scanned to CD by the lab and I have the original color and B&W negatives as well. If I used digital cameras, I'd probably use two separate hard drives (one for incrementals and the other for monthly).
Apple OS X is based on Unix and defragments itself as the need arises. You can buy OS X disk tools, but these often do more harm than good. In the early days of OS X, Norton Utilities actually caused system failures. Within six months the word spread not to use Norton products on OS X.
Today there must be useful OS X utilities and I'm sure people use them. But no one I know who does OS X administration uses anything but the standard Unix utilities.
willie
I only back up to an external HD because my color negatives are scanned to CD by the lab and I have the original color and B&W negatives as well. If I used digital cameras, I'd probably use two separate hard drives (one for incrementals and the other for monthly).
Apple OS X is based on Unix and defragments itself as the need arises. You can buy OS X disk tools, but these often do more harm than good. In the early days of OS X, Norton Utilities actually caused system failures. Within six months the word spread not to use Norton products on OS X.
Today there must be useful OS X utilities and I'm sure people use them. But no one I know who does OS X administration uses anything but the standard Unix utilities.
willie
Rico
Well-known
I program and administer Linux-based machines for my company. Main storage is 5TB configured as 2x 2TB RAID5 plus miscellaneous. This is backed up incrementally over gigabit ethernet to Quantum SDLT II (300 GB native carts), using my own software. Certain tape sets are rotated to a bank vault. In six years, we have suffered two complete RAID5 meltdowns, requiring a complete rebuild from tape.
Whether you use a RAID system like 3Ware or a solitary drive, the periodic reading of all storage is recommended. If you enable SMART, a better measure of predicted failure is reported. In the case of soft errors (the first sign of bit rot), drive firmware will either rewrite the sector in-place and test for correctness, or relocate the sector entirely. The latter makes use of spare sectors that were allocated during the factory format.
Magtape is the only acceptable archival storage on this scale. Optical technology has insufficient density (4.7GB versus 800GB in the consumer realm). Hard drives include an integrated motor with wiring, insulation, and lubrication. Hard drives are also mated with an electronic board with perishables like capacitors, and unit-specific parameters like the defect map. If the motor or circuit board fails, disaster recovery of that drive is expensive or (in later years) impossible. Hard drives should be used for live data and for mirroring, and should be kept spun up 24/7. There is a significant issue around quality of electrical power and thermal cooling, but that is another boring chapter called "Building and Maintaining Your PC Farm".
Long story short, I expect most American families to lose their digital heritage (financial records, e-mail, e-photo albums) soon or sooner. Dear friends, keep shooting film!
Whether you use a RAID system like 3Ware or a solitary drive, the periodic reading of all storage is recommended. If you enable SMART, a better measure of predicted failure is reported. In the case of soft errors (the first sign of bit rot), drive firmware will either rewrite the sector in-place and test for correctness, or relocate the sector entirely. The latter makes use of spare sectors that were allocated during the factory format.
Magtape is the only acceptable archival storage on this scale. Optical technology has insufficient density (4.7GB versus 800GB in the consumer realm). Hard drives include an integrated motor with wiring, insulation, and lubrication. Hard drives are also mated with an electronic board with perishables like capacitors, and unit-specific parameters like the defect map. If the motor or circuit board fails, disaster recovery of that drive is expensive or (in later years) impossible. Hard drives should be used for live data and for mirroring, and should be kept spun up 24/7. There is a significant issue around quality of electrical power and thermal cooling, but that is another boring chapter called "Building and Maintaining Your PC Farm".
Long story short, I expect most American families to lose their digital heritage (financial records, e-mail, e-photo albums) soon or sooner. Dear friends, keep shooting film!
R
rich815
Guest
Rico said:I program and administer Linux-based machines for my company. Main storage is 5TB configured as 2x 2TB RAID5 plus miscellaneous. This is backed up incrementally over gigabit ethernet to Quantum SDLT II (300 GB native carts), using my own software. Certain tape sets are rotated to a bank vault. In six years, we have suffered two complete RAID5 meltdowns, requiring a complete rebuild from tape.
Whether you use a RAID system like 3Ware or a solitary drive, the periodic reading of all storage is recommended. If you enable SMART, a better measure of predicted failure is reported. In the case of soft errors (the first sign of bit rot), drive firmware will either rewrite the sector in-place and test for correctness, or relocate the sector entirely. The latter makes use of spare sectors that were allocated during the factory format.
Magtape is the only acceptable archival storage on this scale. Optical technology has insufficient density (4.7GB versus 800GB in the consumer realm). Hard drives include an integrated motor with wiring, insulation, and lubrication. Hard drives are also mated with an electronic board with perishables like capacitors, and unit-specific parameters like the defect map. If the motor or circuit board fails, disaster recovery of that drive is expensive or (in later years) impossible. Hard drives should be used for live data and for mirroring, and should be kept spun up 24/7. There is a significant issue around quality of electrical power and thermal cooling, but that is another boring chapter called "Building and Maintaining Your PC Farm".
But what's it all mean, Basil?
;-)
S
Socke
Guest
rich815 said:
Ah, behave!
come back to you later, I'm at the japanese twins stage in my list of things to do before I die.