42

Chapter 2. The

proc

File System

  model

  The model name or number of the device.

  settings

  A collection of current parameters of the device. This file usually contains quite a

bit of useful, technical information. A sample

settings

file for a standard IDE hard disk looks

similar to this:

name

value

min

max

mode

bios_cyl

784

0

65535

rw

bios_head

255

0

255

rw

bios_sect

63

0

63

rw

breada_readahead

4

0

127

rw

bswap

0

0

1

r

current_speed

66

0

69

rw

file_readahead

0

0

2097151

rw

ide_scsi

0

0

1

rw

init_speed

66

0

69

rw

io_32bit

0

0

3

rw

keepsettings

0

0

1

rw

lun

0

0

7

rw

max_kb_per_request

64

1

127

rw

multcount

8

0

8

rw

nice1

1

0

1

rw

nowerr

0

0

1

rw

number

0

0

3

rw

pio_mode

write only

0

255

w

slow

0

0

1

rw

unmaskirq

0

0

1

rw

using_dma

1

0

1

rw

2.3.6.

/proc/irq/

This directory is used to set IRQ to CPU affinity, which allows you to connect a particular IRQ to only

one CPU. Alternatively, you can exclude a CPU from handling any IRQs.

Each IRQ has its own directory, allowing for individual configuration of each IRQ. The

/proc/irq/prof_cpu_mask

file is a bitmask that contains the default values for the

smp_affinity

file in the IRQ directory. The values in

smp_affinity

specify which CPUs handle

that particular IRQ.

/usr/src/linux 2.4/Documentation/filesystems/proc.txt

contains more information.

2.3.7.

/proc/net/

This directory provides a comprehensive look at various networking parameters and statistics. Each of

the files covers a specific range of information related to networking on the system. Below is a partial

listing of these virtual files:

  arp

  Contains the kernel's ARP table. This file is particularly useful for connecting hardware

address to an IP address on a system.

  atm

  A directory containing files with various Asynchronous Transfer Mode (ATM) settings and

statistics. This directory is primarily used with ATM networking and ADSL cards.

  dev

  Lists the various network devices configured on the system, complete with transmit and

receive statistics. This file will quickly tell you the number of bytes each interface has sent and

received, the number of packets inbound and outbound, the number of errors seen, the number of

packets dropped, and more.