Other bits are also possible, but less often used. ISP.dip script contains your password to access the ISP's machine. If someone gets that, they can login to your ISP as you, take your email, send email as you, and you might never know. The best cure for that, is for the ISP to log the calling phone number of every caller, and send you a list every week by email. That would also give a vital clue to tracing down whoever is doing the illegal access.
Every device also has permissions similar to files.
Being actual code, the device driver is able to find out more information about you, not just that you opened the device. From the PID, a lot more can be found, such as your login terminal. Most system calls, don't do any checking, which is faster, because they offer the service to anyone. However, setting the system clock, is something that only root should be able to do, so the syscall checks and enforces the permissions. Noe that the permissions on the executable files have to be OK, then again for the system call.