err firenze, an operating system called TENEX does not count. The authorities in viruses, call Brain he first computer virus because there was nothing before that for MS-DOS. Trust me, when Brain came out, the Pentagon freaked out.
Yaara we are talking about history here... and it does n't matter ...k pentagon ki pant gone ho gai... ya nahi..
brain wasn't the first virus, and yes TENEX count. It was one of the first Mainframe OS. Microsoft ki main frame mein entry abhi 2 saal pehley start hoi hia.. !