Red Hat LINUX 7.2 Reference Manual page 97

Section 4.3:Directories in /proc
• pagetable_cache — Controls the number of page tables that are cached on a per-processor
basis. The first and second values relate to the minimum and maximum number of page tables to
set aside, respectively.
Additional information on these various files can be found in /usr/src/linux-2.4/Documen-
tation/sysctl/vm.txt.
4.3.10 /proc/sysvipc
This directory contain information about System V IPC resources. The files in this directory relate to
System V IPC calls for messages (msg), semaphores (sem), and shared memory (shm).
4.3.11 /proc/tty
This directory contains information about the available and currently used tty devices on the system.
Originally called a teletype device, any character-based data terminals are called tty devices.
In Linux, there are three different kinds of tty devices. Serial devices are used with serial connec-
tions, such as over a modem or using a serial cable. Virtual terminals create the common console
connection, such as the virtual consoles available when pressing
Pseudo terminals create a two-way communication that is used by some higher level applications,
such as X11.
The drivers file is a list of the current tty devices in use:
serial
serial
pty_slave
pty_master
pty_slave
pty_master
/dev/vc/0
/dev/ptmx
/dev/console
/dev/tty
unknown
The /proc/tty/driver/serial file lists the usage statistics and status of each of the serial tty
lines.
In order that tty devices can be used in a similar way as network devices, the Linux kernel will enforce
line discipline on the device. This allows the driver to place a specific type of header with every
block of data transmitted over the device, making it possible for the remote end of the connection to
be able to see that block of data as just one in a stream of data blocks. SLIP and PPP are common line
disciplines, and each are commonly used to connect systems to one other over a serial link.
/dev/cua 5
/dev/ttyS 4
/dev/pts 136
/dev/ptm 128
/dev/ttyp 3
/dev/pty 2
/dev/vc/0 4
/dev/ptmx 5
/dev/console 5
/dev/tty 5
/dev/vc/%d 4
at the system console.
[Alt]-[<F-key>]
64-127 serial:callout
64-127 serial
0-255 pty:slave
0-255 pty:master
0-255 pty:slave
0-255 pty:master
0 system:vtmaster
2 system
1 system:console
0 system:/dev/tty
1-63 console
97