Run Level Services

After reading Broch's advice on how to speed up the boot time, he listed many run level services which were not needed and removing disabling them will speed up boot time. this is the post i am referring to...

Suse Linux Support Forums∞

but i was rather apprehensive about disabling them for fear of crippling my system. So I found the below, it's a brief summary of what most of the run level services are for, so you may (or may not) have a little more faith in disabling them for better boot time, and better memory management. to disable any of the below you must go into Yast>System>System Services (RunLevel). and from there you can choose to enable or disable any of the services. Hope this helps.


Service Name Required [Yes/No]
Description
Comments

acon No
Language support
Specifically for the right to left written languages: Arabic, Farsi and Hebrew

acpi Yes
Power Management
acpi is needed for proper function of any power related event, not only on laptops (e.g. suspend, sleep disk spin down)

acpid No
Listening daemon
This listens for and dispatches acpi events from the kernel

adsl No
Internal ADSL switch control
Use this only if you have an internal adsl switch for your internet connection.

alsa No
Advanced Linux Sound Architecture
The only sound system actually included in the kernel

anacron No
Periodic Command Scheduler
a task scheduling tool

apmd No
Power Management
Laptop power management

apmiser No
Power Management
Yet another laptop battery extender

arpwatch No
Ethernet ip address pairing monitor
monitors and logs remote ip addresses with hostnames.

atd No
Periodic Command Scheduler
a task scheduling tool

autofs No
Automount services
one of the several automounting of file systems on demand services. Some of which are distro specific, if the distro you are using has its own automount system, do not use this one.

bluetooth No
The core of Bluetooth
For all Bluetooth services.

bootparamd No
boot server
old means for booting diskless clients / thin clients, the newer method is the zeroconf system.

canna No
Japanese conversion engine

capi4linux No
Basic CAPI subsystem

cpqarrayd No
Hardware Service
Compaq Raid Array Monitor

cpufreq No
Hardware Service
Probes and configured CPU frequency daemon modules

cpufreqd No
Hardware Service
This one will automatically scale cpu frequency to reduce overheating. Should be useful for over-clocking.

crond Yes
Periodic Command Scheduler
THE task scheduling tool.

cups-lpd No
Enables older Linux and commercial Unix systems to connect to cups server
Useful only if you have to allow older systems access to the printers

cups Yes
Common Unix Printing System
A must have to enable printing

cvs No
Concurrent Versioning system
For managing multi user documents.

devfsd No
System Maintenance
This service only cleans up dynamic desktop directories; it is not needed unless your system crashes often.

dhcpd No
The DHCP server
Is your network large enough that static IPs are a pain, then this will make it easier, giving you DHCP IP configuration for your network.

diald No
Smart auto dialer for dialup networking
This service will connect to the network on demand, as in you type an email and hit send, it will connect you, send the email and disconnect you.

dkms No
Autoinstall Boot for DKMS
Distro specific tool, for OEM style installations. This allows for a first boot setting of root password and user name password for regular use. the final configuration of the system.
DKMS stands for Dynamic Kernel Module Support

dm Yes
Display Manager
The core of the x-server, required for using any GUI.

dnbc No
Digital Network Bind Chrooter
This is a simple bash script that puts a BIND server in a chroot jail. Install BIND, launch the script, and restart named

dund No
Bluetooth Dialup networking

fam No
File system Alteration Monitor
Logger for all changes to a file system.

finger No
Remote access of data.
This server will allow remote access of user login data, last login date and time. useful for monitoring employee work habits when you are not in the office, major breach of security, in that you are effectively publishing confidential company data online

freshclam Yes
ClamAV updater
Automatic updates for ClamAV

gpm No
Mouse
Console mode mouse driver

haldaemon Yes
Hardware Monitoring System
This monitors for hardware changes, will alter you to new or altered hardware.

hidd No
Bluetooth H.I.D. Server

hplip No
HP Linux Printing and Imaging
Older version of HP supplied drivers for their all in one products

hpoj No
Pital?init, HP office jet printer drivers
Older drivers for HP office jet, newer drivers are included with cups drivers for the printers

httpd No
Apache Web server
There are two reasons for this to be on a system, one is it is to be used as a Web server, the other it will be a Web site development machine. If neither is true, do not install Apache and this won't be here.

hylafax?server No
Enterprise Fax?modem service
This works for class 1 and class 2 fax modems only. This must be running if you intend to use hylafax to send a fax through the modem. This is not the only fax tool available.

ibod No
ISDN MPPP bandwidth on demand
Useful with dialup networking, this will connect as needed to the network.

identd No
Identification through TCP connection

imaps No
secure IMAP server

imaps No
IMAP server

iplog No
Logs TCP, UDP, ICMP connections with hostname of remote host
Useful network monitoring tool.

ipop2 No
POP2 mail server

ipop3 No
POP3 mail server

ipsec No
Encrypted and Authenticated communications
KLIPS is the kernel half, PLUTO is the user space half. very useful for remote access situations

iptables Yes
kernel based Packet Filtering firewall
All good Linux firewalls are based on this service.

ipvsadmin No
Linux Kernel IP virtual server
This is one of the oldest networking systems in Linux, not used very much any more.

irda No
Infra Red Device Interface
Older wireless device support

keytable Yes
keyboard map
This tells the system exactly which keyboard you are using.

kheader No
Boot Services
This automatically regenerates the kernel header in /boot

lads No
Login Anomaly Detection System
A tool to track login attempts and warn of attempted intrusion.

laptop?mode No
Power Management
A tool to reduce power consumption, extending the life of the laptop battery

leafnode No
NNTP service for X?INETD

lisa No
LAN information server

lmsensors No
Hardware health monitor
This requires that the mainboard of the system supports and has monitoring systems in place, such as the CPU temperature and voltage monitors.

mailman No
GNU Mailing List Manager
A commonly used mailing list tool, with a Web interface for administration, written in Python. It allows list members to communicate by sending an email to one address, and replying to the same address. Can also be used to send out newsletters / product updates to those that requested such

mandi No
Interactive Firewall
Special service to allow for temporary wireless access to the system, will open the iptables firewall for current session only access for wireless devices, on user approval only, not automatically.

mdadm No
Monitoring Service for software raid
This also is a management tools for said software raid volumes.

mdnsresponder No
Zeroconf DNS configuration tool

messagebus Yes
Event monitoring service
This one sends broadcast messages to all users when needed, like the server is going down for reboot.

mon Yes
System Monitoring daemon
A lot of system services require this in order to function

mysqld No
MySQL server
If you don't need this database, why turn it on?

named No
BIND server
yes, the infamous name server.

netplugd No
Network Card daemon
This service monitors the network interface, turning it off or on depending on signal, used mainly for laptops that may not always be connected.

network Yes
Networking
This turns the network card on, or powers the modem.

nfs No
Network File Share
This enables the clients to access NFS shares, it is required for the client machines in an NFS system.

nfsfs No
The Network File Share Server
This should only be active on the network server

nfslock No
NFS file locking
This should only be active if you are using NFS networking / file share functionality.

nifd No
Howl Client
This provides ipv4 link?local services for zeroconf networks / systems

nscd No
Password and group lookup service
name service cache daemon, it is a daemon that provides a cache for the most common name service requests

ntpd No
Version 4 of the NTP server

numlock No
number lock light control
This will keep the Numlock activated, turning the keyboard number pad on.

oki4daemon No
compatibility daemon for OKI4 and compatible winprinters
only useful if you have one of these printers

pand No
Bluetooth Personal Area Networking
For home area Bluetooth based networking.

partmon Yes
Partition Monitoring
This service keeps track on free space on mounted partitions. used by most file system browsers for calculating free space on a given partition.

pcmcia No
Personal Computer Memory Card International Association

pg_autovacum No
PostgreSQL maintenance
This will automatically run the vacuum needed by PostgreSQL to reduce disk space, pulling temp tables from the db as well as deleting temp files created by PostgreSQL.

pop3s No
Secure POP3 server
SSL enabled POP3 server

portmap No
RPC support
Support for those rare apps that use rpc.

Postgresql No
The Postgresql Database Engine
You only need this if you are either running a postgresql db drives application or are developing one.

postfix No
email server
asendmail compatible email server, newer than sendmail itself, becoming more commonly used than sendmail.

pptp No
a service required for tunneling with older (NT and maybe w2k) windows VPN, currently replaced with IPSEC

prelude No
IDS
Intrusion Detection system

psacct No
Process Accounting
A Tracker of active processes, a waste of resources really

rawdevices Yes
Assigns rawdevices to blocks for use
This is needed for DVDS, and oracle DBMS among other things

rsync No
Remote Synchronization
A server to enable remote synchronization of files in a specified directory tree. Commonly used for maintaining mirror sites, can also be used to keep company files current for backup purposes.

saned No
Network Scanner Service
To provide access to your scanner from any workstation in the network.

shorwall Yes
Firewall
A very good IPTables based firewall. shorewall is does not run continuously, it merely allows easy configuration of firewall rules. So this is useful only for users not familiar with iptables.

smartd No
Self Monitor Service
For OS access to smart enabled devices, this will allow Linux to tell you if the device is starting to go bad, but relies on the device smart feature for accuracy.

smb No
Samba Network Services
This provides the samba services to enable Windows network compatibility.

snmpd No
Simple Network management Protocol
For use in a small [ home office ] network

sound No
Sound System
This is the core of the Linux sound system, nice for desktops, a waste of resources on a server

squid No
Caching Tool
Used to cache Web pages and DNS entries

ssh?xinetd No
OpenSSH server for x?inetd
a run on demand version of OpenSSH

sshd No
OpenSSH server
Only turn this on if you require SSH access to your system, and are not going to use the x?inetd version.

subversion No
Concurrent Versioning system
New alternative to CVS

swat No
Samba Web Administration Tool
Web based Samba administration

syslog Yes
System Logging
A Required service, it controls all logging on the entire system.

tmdns No
Multicast dns responder
For use in zeroconf environments

ultrabayed No
ThinkPad tool
This detects the presence of the ultrabay for your IBM ThinkPad and starts / stops the IDE interface as appropriate.

upsd No
NUT daemon and drivers
An uninterrupted power supply monitoring and reporting tool. This tool reports to a central site to generate a database on ups statistics.

upsmon No
Monitoring tool for UPS
This will monitor the status of the ups, and shut the system down when it's running low.

vncserver No
Server for Virtual network computing
Very useful for using VNC in projects.

Webmin No
Remote Administration tool
Distro Agnostic Remote administration tool. Useful for when the machine will not be physically accessible at all times; such as Web server farm.

winbind No
winbind is required for samba domain authentication, but it is not required for simple sambaworkgroup authentication.

wine No
Wine Is Not an Emulator
This enables running MS Windows executables in Linux. WINE is a limited version of the commercial product Crossover Office.

wlan No
Control Daemon
This Controls services, it is not commonly used as the services are generally controlled through the init process.

x?inetd Yes
Server for monitoring and controlling other servers
This is required service, and it actually reduces CPU load on a server. if you need SSH, ftp, etc but not all the time, the x?inetd version will start them on request, even remote request. This allows for them to be available, but frees the clock?cycles if they are only being used a few times a day / week.

xfs No
X Font Server
Not needed on suse, nor most other current distros

ypbind No
Name Server for Sun's YP server
This is for GLIBC based NIS / YP networked systems.


This has been edited since the article where this information was found
http://articles.techrepublic.com.com/5100-3513-6018195.html
was wrong in a few places, it has been edited to the best of my ability thanks to the user Broch. Many thanks to the article and Broch for helping me in making this Wiki.