After the virus has been loaded into memory, it infects any executable file by writing itself to the end of the binary.
The virus does not infect files that are larger than 65,535 bytes.
The TSR memory usage is 1,024 bytes.
The virus activates on every January 31 since 1993 (before 1993 it just spreads itself) by displaying a colored text on the upper right hand corner and removing the partition table of the drive:
AVALON por OSoft
The user may access the contents only if the machine has not been rebooted.