High Quality Content by WIKIPEDIA articles! AIDS II is a companion computer virus, which infects COM files. It was first discovered in April 1990, and is a variant of AIDS. Unlike other generic file infectors, AIDS II was the first known virus to employ what could be called a "corresponding file technique" of infection so that the original target EXE file is never changed. The virus takes advantage of the DOS feature where if a file exists in both COM and EXE form, the COM file is executed. When an "infected" file is executed, since a corresponding COM file exists, the COM file containing the viral code is executed. The virus first locates an uninfected EXE file in the current directory and creates a corresponding (or companion) COM file with the viral code. These COM files will always be 8,064 bytes in length with a file date/time of the date/time of infection. After creating the new COM file, the virus then plays a melody and displays the following message