|Type||Boot sector virus|
|Place of Origin||Germany|
Screen is an early memory resident boot sector virus for the Atari ST.
When a disk infected with Screen is booted, it becomes memory resident. It hooks the Hdv_bpb vector (important to the Atari OS BIOS), 200 Hz System Clock vector and the Etv_critic vector. It infects non-executable disks on Drive A:. The virus's payload routine where it blackens the screen runs 54 minutes after the virus goes into memory.
It was discovered by Carsten Frischkorn, using the handle "virentod" ("virus death" in German) in Germany in mid summer of 1988. Screen is very simple to remove from memory with a reset and can be neutralized with common antivirus utilities available at the time. It only works on ROMS dated 1986.06.02, likely targeting the German TOS 1.00.
Richard Karsmakers. THE KNOWN VIRUSES ON ATARI TOS COMPUTERS AND THEIR SYMPTOMS.
Hallvard Tangeraas. Common viri on the Atari ST.