Why is issuing a trap not a priviledged task?

Question

In solutions to a question on the book "Operating Systems Concepts" it indicates that issuing a trap not a privileged task. Why is that so?

score 3 · Accepted Answer · answered Apr 26 '12 at 20:26

3

Some instructions need special privileges to run at all, which most of the time means only the OS gets to execute them.

Most user processes (programs) will need to issue a trap / exception to get the OS to run these instructions.

answered Apr 26 '12 at 20:26

ChristopheD

score 2 · Answer 2 · answered Apr 26 '12 at 20:20

2

If it were a privileged operation, it wouldn't be possible for a process to issue a system call.

answered Apr 26 '12 at 20:20

cnicutar

2 Answers2