6ddf213d5d
1999-05-16 Martin Baulig <martin@home-of-linux.org> * white-paper.texi: Initial version of the LibGTop White Paper.
42 lines
1.3 KiB
Plaintext
42 lines
1.3 KiB
Plaintext
@node White Paper, Reference Manual, About, Top
|
|
@chapter LibGTop White Paper
|
|
|
|
@menu
|
|
* Introduction::
|
|
@end menu
|
|
|
|
@node Introduction, , White Paper, White Paper
|
|
@section Introduction
|
|
|
|
Many modern UNIX systems like Solaris, BSD or Digitial Unix only allow
|
|
priviledged processes to read information like CPU and Memory Usage or
|
|
information about running processes.
|
|
|
|
@itemize @bullet
|
|
@item
|
|
BSD, for instance, doesn't have any other way to get those data than reading
|
|
directly from @file{/dev/kmem} and you need to be in the @code{kmem} group to
|
|
be able to read this.
|
|
|
|
@item
|
|
Other systems, like Digital Unix, allow all users to get things like CPU and
|
|
Memory statistics, but only root may read information about any process other
|
|
than the current one (you may not even get information about your own processes
|
|
if you're not root).
|
|
|
|
@item
|
|
Linux has a very nice @file{/proc} filesystem, but reading and parsing
|
|
@file{/proc} is very slow and inefficient.
|
|
|
|
@item
|
|
Solaris is a bit better, but you still need to be in the @code{sys} group or
|
|
even root to get some data.
|
|
@end itemize
|
|
|
|
Because of this system utilities like @code{ps}, @code{uptime} or @code{top}
|
|
often are setgid kmem or setuid root. Usually, they're also very specific to
|
|
the system they're written for and not easily portable to other systems without
|
|
a lot of work.
|
|
|
|
|