Dell PowerVault 124T - Manual (Page 21)

LTO Media Handbook 21
Erasing a Pre-Written LTO Tape
CAUTION: Do not bulk erase Ultrium format cartridges. This destroys
pre-recorded servo information and renders the cartridge unusable.
The erase feature in the backup software is the preferred method for erasing
an LTO tape. To prevent erasing a tape, slide the write-protect switch to the
right.
NOTE: Write-protection does not prevent a cartridge from being erased by
bulk-erasure or degaussing.
Figure 1-1. Setting the Write-Protect Switch
1 write-protect switch