[Coco] Possible CoCo Bulletin Board forum
snhirsch at gmail.com
Thu Dec 25 13:20:02 EST 2008
On Thu, 25 Dec 2008, Gene Heskett wrote:
>> It's seriously difficult to kill data on a DLT cartridge. I've personally
>> seen cases where tapes run over a bulk eraser were still readable! The
>> drives use read-after-write to ensure integrity and will redo any blocks
>> that fail CRC (up to a limit). The lack of read-back is a serious issue
>> for the rotary-head transports which are mechanically incapable of it (at
>> least AFAIK).
> Bulk erasers don't have the cajones to erase a data or vieo tape unless it
> says Garner on it.
Ah. Now I know what to look for! I've been using an older Nortronics
unit intended for reel-to-reel audio tape. Whenever I have to wipe a data
cartridge, I place a U-shaped piece of steel over the top to focus the
flux lines. Buzzes like a b*tch, but gets the job done :-).
> Anyway, the virtual tapes, on a 500GB hard drive, are many times more
> dependable, I've not lost a byte since. And I don't worry about backups, I
> have a user named amanda who runs herself evey morning at a little after 1
> and does all that without any interference from me.
I would be very concerned about putting all my eggs in one basket like
that. My working theory on hard drives is that there are two types:
Those that have failed already and those that are about to.
That's why data-retention experts recommend against using RAID for
archival purposes, BTW. Just because the chances of losing >1 drive in a
RAID-5 array are infinitesmal does not mean it cannot happen.
I didn't realize that rotary head devices were capable of supporting
read-after-write. Thanks for the update!
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