Digger is a memory resident virus. It hooks INT 8 and 21h, and infects .COM, .EXE and .OVL files that are executed. Some time after activation, the virus "launches" several balls of different colors randomly moving around the screen (the effect is similar to the ball movement of the "Ping-Pong" virus). On Tuesday, the infected .EXE files format the disks. The virus contains the following text:
(C) David Grant Virus Research 1991 PCVRF Disribuite this virus freely!!!...ah...John...Fuck You!
While installing, it copies itself to the memory at address 9000:0000, and does not fix the MCB list that may halt a PC. It infects some files in an incorrect way. It can halt the system.
It also hooks INT 10h, and at 10:00 and 17:00, it draws a picture.
It contains the following text string:
DIGGER IS MY LOVE!