KDED

Central daemon of KDE work spaces

Introduction

KDED stands for KDE Daemon which isn't very descriptive. KDED runs in the background and performs a number of small tasks. Some of these tasks are built in, others are started on demand.

Built in tasks

• Checking for newly installed software and updating ksycoca when new software is detected. Updating of ksycoca is done by the program kbuildsycoca which gets started by kded. When kded is first started it always runs kbuildsycoca to ensure that ksycoca is up to date.
• Checking for newly installed update files. Applications can install *.upd update files. These *.upd files are used to update configuration files of users, primarily when new versions of applications are installed with (slightly) different configuration file formats. Updating of configuration files is done by kconf_update. kded starts kconf_update when it detects a new update file. When kded is first started it always runs kconf_update to ensure that it has not missed any update files. kconf_update keeps track of which update files have been processed already in the config-file kconf_updaterc. It only performs a certain update once.

Configuration of built in tasks.

The built in tasks have some configuration options that can be changed by editing the kdedrc configuration file. Changes need to be made with a text editor, there is no GUI available. All options are listed under the [General] group:

HostnamePollInterval: This can be used to adjust the time interval at which the hostname is checked for changes. The time is specified in milliseconds and has a default of 5000 (5 seconds).

CheckSycoca: This option can be used to disable checking for new software. ksycoca will still be built when kded starts up and when applications explicitly request a rebuild of the ksycoca database. The user can also manually rebuild ksycoca by running the kbuildsycoca program. The default value of this option is "true". Checking can be disabled by setting this option to "false".

CheckUpdates: This option can be used to disable checking for update files. kconf_update will still be run when kded starts up. The default value of this option is "true". Checking can be disabled by setting this option to "false".

CheckHostname: This option can be used to disable checking for hostname changes. The default value of this option is "true". Checking can be disabled by setting this option to "false".

Example kdedrc file with default values:

[General]
HostnamePollInterval=5000
CheckSycoca=true
CheckUpdates=true
CheckHostname=true
CheckFileStamps=true
DelayedCheck=false

If FAM or DNOTIFY is not available, the filesystem will be polled at regular interval for any changes. Under the [DirWatch] group in the kdeglobals file the following options are available to adjust the polling frequency:

PollInterval: This can be used to adjust the time interval at which the local filesystem is checked for new software or update files. The time is specified in milliseconds and has a default of 500 (0.5 seconds).

NFSPollInterval: This can be used to adjust the time interval at which remote filesystems, such as NFS or Samba, are ebing checked for new software or update files. The time is specified in milliseconds and has a default of 5000 (5 seconds).

The above options are not used when FAM is used to watch for changes in the filesystem, or when DNOTIFY is used. Specifying larger intervals may reduce the CPU load and/or network traffic. Shorter intervals are not recommended.

Please note that in previous versions of KDE these options where listed in the kderc file.

Example kdeglobals fragment:

[DirWatch]
PollInterval=500
NFSPollInterval=5000

KDED modules

Some things can be greatly simplified if they can be coordinated from a central place. KDED has support for modules that will be demand-loaded whenever an application attempts to make DBus call to the module. This can be useful for central administration tasks.

See docs/HOWTO.