The Brain boot sector virus was first released. Brain is considered to be the first computer virus for MS-DOS that works by infecting the boot sector of storage media formatted with the DOS File Allocation Table (FAT) file system.
The virus was able to infect a computer by replacing the healthy boot sector of a floppy disk to another sector and marked it as bad, and then replace it with a copy of the virus. The virus slows down the floppy disk drive and makes seven kilobytes of memory unavailable to DOS.
The program was written by two brothers, Basit Farooq Alvi and Amjad Farooq Alvi, from Lahore, Punjab, Pakistan. The brothers told TIME that they had written it to protect their heart monitoring software from piracy, and it was supposed to target copyright infringers only.
The virus came complete with the brothers' address and three phone numbers, and a message that told the user that their machine was infected and to call them for inoculation:
Welcome to the Dungeon © 1986 Brain & Amjads (pvt). BRAIN COMPUTER SERVICES 730 NIZAM BLOCK ALLAMA IQBAL TOWN LAHORE-PAKISTAN PHONE: 430791,443248,280530. Beware of this VIRUS.... Contact us for vaccination...