Datasheet

“main” (Installation and Administration) — 2004/6/25 — 13:29 — page 249 — #275
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10
Special Features of SUSE LINUX
Memory amounts must be specified in KB. For more detailed information,
see man bash.
Note
Not all shells support ulimit directives. PAM (for instance,
pam_limits) offers comprehensive adjustment possibilities if
you depend on encompassing settings for these restrictions.
Note
10.2.6 The free Command
The free command is somewhat misleading if your goal is to find out how
much RAM is currently being used. The relevant information can be found
in /proc/meminfo. These days, users with access to a modern operating
system, such as Linux, should not really need to worry much about mem-
ory. The concept of available RAM dates back to before the days of unified
memory management. The slogan free memory is bad memory applies well to
Linux. As a result, Linux has always made the effort to balance out caches
without actually allowing free or unused memory.
Basically, the kernel does not have direct knowledge of any applications or
user data. Instead, it manages applications and user data in a page cache. If
memory runs short, parts of it are written to the swap partition or to files,
from which they can initially be read with the help of the mmap command
(see man mmap).
Furthermore, the kernel also contains other caches, such as the slab cache,
where the caches used for network access are stored. This may explain dif-
ferences between the counters in /proc/meminfo. Most, but not all of
them, can be accessed via /proc/slabinfo.
10.2.7 The File /etc/resolv.conf
Domain name resolution is handled through the file /etc/resolv.conf.
Refer to Section 21.7 on page 458.
This file is updated by the script /sbin/modify_resolvconf ex-
clusively, with no other program having permission to modify /etc/
resolv.conf directly. Enforcing this rule is the only way to guarantee
that the system’s network configuration and the relevant files are kept in a
consistent state.
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SUSE LINUX Enterprise Server