Disney web site - CHAPTER 31 OPTIMIZING YOUR SYSTEM 449 Table
CHAPTER 31 OPTIMIZING YOUR SYSTEM 449 Table 31-1. Ubuntu Run Level Services (Continued) Service Description anacron Runs scheduled tasks, as described in Chapter 33. It allows the running of housekeeping tasks, so you shouldn t disable it (although it s not essential to the running of Ubuntu). apmd Activates the Advanced Power Management (APM) function. Nowadays, APM has been superseded by ACPI, so if you re sure your computer uses ACPI, you can disable this service. atd Scheduling service, as discussed in Chapter 33. If you don t use the at command, you can disable this. bluez-uti[ls] Required for the correct functioning of Bluetooth hardware (mobile phones, wireless headphones, and so on). If you don t use Bluetooth, you can disable this. bootlogd Logs boot messages. If you re sure you ll never, ever examine the boot log, as is sometimes necessary when problem solving, you can disable this service. cron Another scheduling service, as discussed in Chapter 33. Many housekeeping tasks are run via cron, so this should not be disabled (although it s not essential to the running of Ubuntu). cupsys Part of the printing subsystem. If you don t use a printer, either attached directly or across a network, this can be disabled. dbus Allows software to communicate with other software. It s vital, so don t disable it. dns-clean Part of the ppp subsystem that s designed to facilitate modem network connections. If you use a modem of any type, don t disable this. If you use an Ethernet or wireless connection, it can be disabled. evms Controls the Enterprise Volume Management Subsystem, which is used to manage multiple disk setups. If your computer doesn t use RAID or any other kind of logical partitioning scheme, you can disable this. If your computer has only one hard disk, you can definitely disable this service. fetchmail System service that can collect mail from remote mail servers for local delivery. It can be disabled on most systems, unless your mail client specifically uses it. The default e-mail client under Ubuntu, Evolution, doesn t use fetchmail. gdm Starts the GNOME desktop subsystem and therefore the X server. Don t disable this, unless you want a command-prompt-only run level. halt Used to shut down the system. Don t disable this service. hdparm Runs the hdparm.conf script, which allows you to optimize your hard disk settings. Don t disable this. hotkey-se[tup] Configures various additional keys on some notebook computers, such as those that allow the dimming of the screen. You can disable this, unless you re using a notebook computer. hotplug Controls systems such as USB and PCMCIA that allow hardware to be inserted when the computer is switched on. Also controls some sound devices. Don t disable this.