Linux Devices
In Linux you have various special files in
/dev. These files are called devices files. In
the Unix world accessing hardware is different. There you have a
special file which actually runs a driver which in turn accesses the
hardware. The device file is an interface to the actual system
component. Files under /dev also behave
differently than ordinary files. Below are the most important device
files listed.
fd0
First Floppy Drive
fd1
Second Floppy Drive
hda
IDE Hard disk / CD-ROM on the first IDE port (Master)
hdb
IDE Hard disk / CD-ROM on the first IDE port (Slave)
hdc
IDE Hard disk / CD-ROM on the second IDE port (Master)
hdd
IDE Hard disk / CD-ROM on the second IDE port (Slave)
hda1
First partition of the first IDE hard disk
hdd15
Fifteenth partition of the fourth IDE hard disk
sda
SCSI Hard disk with lowest SCSI ID (e.g. 0)
sdb
SCSI Hard disk with next higher SCSI ID (e.g. 1)
sdc
SCSI Hard disk with next higher SCSI ID (e.g. 2)
sda1
First partition of the first SCSI hard disk
sdd10
Tenth partition of the fourth SCSI hard disk
sr0
SCSI CD-ROM with the lowest SCSI ID
sr1
SCSI CD-ROM with the next higher SCSI ID
ttyS0
Serial port 0, COM1 under MS-DOS
ttyS1
Serial port 1, COM2 under MS-DOS
psaux
PS/2 mouse device
gpmdata
Pseudo device, repeater data from GPM (mouse) daemon
cdrom
Symbolic link to the CD-ROM drive
mouse
Symbolic link to the mouse device file
null
Everything pointed to this device will disappear
zero
One can endlessly read zeros out of this device
Setting Up Your Mouse
The mouse can be used in both the Linux console (with gpm) and the X window
environment. The two uses can be made compatible if the gpm repeater is used
to allow the signal to flow to the X server as shown:
mouse => /dev/psaux => gpm => /dev/gpmdata -> /dev/mouse => X
/dev/ttyS0 (repeater) (symlink)
/dev/ttyS1
Set the repeater protocol to be raw (in /etc/gpm.conf) while
setting X to the original mouse protocol in /etc/X11/XF86Config
or /etc/X11/XF86Config-4.
This approach to use gpm even in X has advantages when the mouse is
unplugged inadvertently. Simply restarting gpm with
user@debian:# /etc/init.d/gpm restart
will re-connect the mouse in software without restarting X.
If gpm is disabled or not installed with some reason, make sure to set X to
read directly from the mouse device such as /dev/psaux. For details, refer
to the 3-Button Mouse mini-Howto at
/usr/share/doc/HOWTO/en-txt/mini/3-Button-Mouse.gz,
man gpm,
/usr/share/doc/gpm/FAQ.gz, and
README.mouse.
For PowerPC, in /etc/X11/XF86Config or
/etc/X11/XF86Config-4, set the mouse device to
"/dev/input/mice".
Modern kernels give you the capability to emulate a three-button mouse
when your mouse only has one button. Just add the following lines to
/etc/sysctl.conf file.
# 3-button mouse emulation
# turn on emulation
/dev/mac_hid/mouse_button_emulation = 1
# Send middle mouse button signal with the F11 key
/dev/mac_hid/mouse_button2_keycode = 87
# Send right mouse button signal with the F12 key
/dev/mac_hid/mouse_button3_keycode = 88
# For different keys, use showkey to tell you what the code is.
Disk Space Needed for Tasks
The base sarge installation for i386, including all standard packages,
requires 178MB of disk space.
The following table lists sizes reported by aptitude for the tasks listed in
tasksel. Note that some tasks have overlapping constituents, so the total
installed size for two tasks together may be less than the total obtained by
adding the numbers up.
Task Installed Download Space Needed
Size (MB) Size (MB) To Install (MB)
Desktop 1537 521 2058
Web server 71 21 92
Print server 240 83 323
Mail server 41 12 53
File server 85 34 119
SQL database 108 33 141