randeep Posted November 16, 2009 Report Share Posted November 16, 2009 Hello All, We have used Retrospect 7.6.123 on Windows 2003 server with LTO 4 tape drive, some of the tapes were marked WORM after writing 400 GB of data. I just want to know whether it will be possible to reuse these tapes. Is there some mechanism through which we can erase these tapes? Also one more query is that, we have taken backup to tape through Retrospect backup computer on windows. Can we erase these tapes through Retrospect backup computer on mac? Quote Link to comment Share on other sites More sharing options...
Lennart_T Posted November 16, 2009 Report Share Posted November 16, 2009 There are two kinds of LTO4 tapes: WORM and ordinary/standard. WORM=Write Once Read Many. They are intended for archiving backups and can NOT be reused. Look at the tapes: Are they really WORM tapes or not? Quote Link to comment Share on other sites More sharing options...
rhwalker Posted November 16, 2009 Report Share Posted November 16, 2009 Also one more query is that, we have taken backup to tape through Retrospect backup computer on windows. Can we erase these tapes through Retrospect backup computer on mac? As long as they are not WORM tapes, yes. There have been some bugs from time to time with some tape vendors' drives where the tapes couldn't be erased. In general, those bugs have been fixed. Most vendors also have diagnostic utilities that will allow you to erase a tape. In Retrospect, there are two types of "erased" tapes: (1) tapes with nothing on them; and (2) tapes with a Retrospect backup set header (naming the tape member) but no data. When you "erase" a tape in Retrospect, it puts down the Retrospect backup set header with an EOT after that (two file marks). Retrospect also marks the appropriate backup set as "empty" when you erase the members of that backup set. Obviously, if you erase a Windows backup set tape on a Mac Retrospect, there is no way to communicate back to the Windows Retrospect that the members no longer exist except to manually mark them as "missing" in the Windows Retrospect program. Russ Quote Link to comment Share on other sites More sharing options...
emulator Posted November 17, 2009 Report Share Posted November 17, 2009 Also, the tape has to physically be a WORM tape. For example: LTO4 WORM Picture If the tape is not branded "WORM", then it can be erased. Otherwise, you can't erase it. This is mainly for regulatory compliance standards to prevent the tapes from being "doctored" after the fact. Quote Link to comment Share on other sites More sharing options...
Ramon88 Posted November 17, 2009 Report Share Posted November 17, 2009 Just interested, do you know if this is because of the cartridge, tripping a certain state of the drive, or is the medium used (the tape) made of a different material that really is 'write once'? Or else, could one open a cartridge and take the WORM tape out and place it in a normal cartridge. Would it still be WORM? Or could one tamper with the drive so it can see the WORM tape as a regular tape? Quote Link to comment Share on other sites More sharing options...
rhwalker Posted November 17, 2009 Report Share Posted November 17, 2009 There is a chip in the cartridge that tells the drive it's a WORM, and the drive writes a WORM tag to each record. See, for example, Wikipedia - LTO3 Worm and Wikipedia - Logical WORM But a big magnet can still erase everything. Russ Quote Link to comment Share on other sites More sharing options...
emulator Posted November 18, 2009 Report Share Posted November 18, 2009 This should tell you everything that you ever wanted to know about WORM/LTO: LTO WORM Paper Note: you'll have to register to download the paper. Quote Link to comment Share on other sites More sharing options...
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