by the way, can some one tell me what does one require to develop virus for the linux kernel or gnu OS? because a file security or for that matter execution rights are fixed as per the user. so if a file is having executable permission on my machine under the user krmane, how will it have same permission for user roni on another machine (or even on the same machine for that matter?) and by the way if I develop a virus (first define that term in context of linux) I will only end up destroying files in my own user space. viruses r supposed to multiply and execute on all the machines they attack. how can virus developers ensure this? I get the feeling that unless all computers are connected to the internet at one given point of time and all are logged in as root and then make entire system read/write including /usr/bin and /bin etc, there can't be a concept of virus for linux and the above mentioned condition is a very distent co insidence. regards, Krishnakant.