Installation guide
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.