WordNet (r) 3.0 (2006):

scag
    n 1: street names for heroin [syn: big H, hell dust, nose
         drops, smack, thunder, skag, scag]

The Free On-line Dictionary of Computing (19 January 2023):

scag

   To destroy the data on a disk, either by corrupting the
   file system or by causing media damage.

   Compare scrog, roach.

   [Jargon File]

   (1995-01-16)


The Jargon File (version 4.4.7, 29 Dec 2003):

scag
 vt.

    To destroy the data on a disk, either by corrupting the filesystem or by
    causing media damage. “That last power hit scagged the system disk.”
    Compare scrog, roach.