# Linux Devices

In Linux various special files can be found under the directory `/dev`. These files are called device files and behave unlike ordinary files. The most common types of device files are for block devices and character devices. These files are an interface to the actual driver (part of the Linux kernel) which in turn accesses the hardware. Another, less common, type of device file is the named pipe. The most important device files are listed in the tables below.

`sda` | First hard disk
`sdb` | Second hard disk
`sda1` | First partition of the first hard disk
`sdb7` | Seventh partition of the second hard disk

`sr0` | First CD-ROM
`sr1` | Second CD-ROM

`ttyS0` | Serial port 0, also referred to as COM1
`ttyS1` | Serial port 1, also referred to as COM2
`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` | Anything written 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. Normally, this is a simple matter of installing `gpm` and the X server itself. Both should be configured to use `/dev/input/mice` as the mouse device. The correct mouse protocol is named `exps2` in gpm, and `ExplorerPS/2` in X. The respective configuration files are `/etc/gpm.conf` and `/etc/X11/xorg.conf`.

## Disk Space Needed for Tasks

A standard installation for the amd64 architecture, including all standard packages and using the default kernel, takes up &std-system-size;MB of disk space. A minimal base installation, without the Standard system utilities task selected, will take &base-system-size;MB.

In both cases this is the actual disk space used after the installation is finished and any temporary files deleted. It also does not take into account overhead used by the file system, for example for journal files. This means that significantly more disk space is needed both during the installation and for normal system use.

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 up the numbers.

By default the installer will install the GNOME desktop environment, but alternative desktop environments can be selected either by using one of the special installation images, or by specifying the desired desktop environment during installation (see pkgsel).

Note that you will need to add the sizes listed in the table to the size of the standard installation when determining the size of partitions. Most of the size listed as Installed size will end up in `/usr` and in `/lib`; the size listed as Download size is (temporarily) required in `/var`.

Task | Installed size (MB) | Download size (MB) | Space needed to install (MB)
Desktop environment |  |  |
• GNOME (default) | &task-desktop-gnome-inst; | &task-desktop-gnome-dl; | &task-desktop-gnome-tot;
• KDE Plasma | &task-desktop-kde-inst; | &task-desktop-kde-dl; | &task-desktop-kde-tot;
• Xfce | &task-desktop-xfce-inst; | &task-desktop-xfce-dl; | &task-desktop-xfce-tot;
• LXDE | &task-desktop-lxde-inst; | &task-desktop-lxde-dl; | &task-desktop-lxde-tot;
• MATE | &task-desktop-mate-inst; | &task-desktop-mate-dl; | &task-desktop-mate-tot;
• Cinnamon | &task-desktop-cinnamon-inst; | &task-desktop-cinnamon-dl; | &task-desktop-cinnamon-tot;
Web server | &task-web-inst; | &task-web-dl; | &task-web-tot;
SSH server | &task-ssh-inst; | &task-ssh-dl; | &task-ssh-tot;

If you install in a language other than English, `tasksel` may automatically install a localization task, if one is available for your language. Space requirements differ per language; you should allow up to 350MB in total for download and installation.