🚀 go-pugleaf

>From:    bill.lambdin%acc1bbs@ssr.com (Bill Lambdin)

>The Music Bug virus isn't generally destructive, but the FAT table 
>structure on hard drives gives some weird effects occasionally.

Not quite. The MUSIC-BUG is not *intentionally* destructive however
mistakes do cause damage since this virus makes assumptions about disk
structure that works only on some floppies and on no hard disks.

The virus tries to create a "haven" for its code by searching for
unused sectors and allocating them (six or seven as I recall).
Unfortunately, while the chosen clusters are "safe", in computing the
register values for a cluster/sector translation the M-B makes
mistakes that cause the virus to write to a different set of sectors
which may be in use.

The virus also makes a single byte change to the Boot Parameter Block
which renders removal via SYS C: unusable since the disk becomes
unbootable.  For some time this led to the opinion that recovery was
impossible but most vendors now use a equally simple recovery method
that works (think it took less than 30 bytes).

The most common vector was via a graphics driver disk furnished with
certain computer systems and though the manufacturer was notified, I
have never seen any indication that the disks were withdrawn/replaced.

					Unseasonably warm & humid,

							Padgett