[Info-vax] strange backup behavior

[glen herrmannsfeldt]

B Hobbs <bdhobbs18 at acm.org> wrote:

< I've noticed that the more data on our backup SDLT tape, the longer it
< takes to add additional files to the same tape.  When a file of about
< 35 blocks (BACKUP-STUFF.COM;67) is backed up at the beginning of the
< tape, that backup takes less than a minute.  Backing up the same file
< after about 45 gigabytes of other backup files takes over 30 minutes.

As I understand it, LTO knows where files (tape marks) are on the
tape using a small EEPROM in the cartridge.  I don't know that SDLT
does that, which would mean reading the tape until the end, then
start writing.  I don't know so many details about SDLT, though.

-- glen