With zapdvb (and most other DVB software) only one user at a time can use a DVB card. A user can be an interactive session (called foreground in this text) or some recording batch (called background in this text). One of zapdvb's features is that it assigns different priorities to fore- and background jobs. A one-time recording (via at) has priority above repeated recordings (via cron) and both have priority over a foreground job. In other words: a background job can stop a foreground job to get access to the DVB card.
Without family mode this works only if all activities are triggered by the same user (e.g. all processes use the same user id). Think of the following problem: you used zapdvb to schedule a movie recording in your absence. Now, shortly before recording starts, someone of your family uses zapdvb from a different user id to watch life TV. Without family mode your recording job will fail to get access to the DVB hardware, as it is used by someone else and zapdvb does not know by whom or how to stop that other user.
Family mode can help in such situations and
usually it does not introduce new problems, except that you cannot
directly stop background jobs from the GUI. This behaviour is by
design: use zapmcc --kill from a command window to
stop the current background job.
Reminder: You must configure family mode on the server side if you want to offer remote mode to clients.
By help of the sudo command
background jobs (and the remote mode server) will be granted
permission to use the kill command to send signals to
other jobs. All users (and jobs) will use the same process status
information file located in
/usr/local/share/zapdvb/home/.zapdvb_run . Please use
the /usr/local/share/zapdvb/setup conf command to
configure your system (e.g. to create the zapdvb
user and to modify /etc/sudoers).
Reminder: You will
also have to enable the mainuser=zapdvb entry in the
zapdvb section of
/usr/local/share/zapdvb.conf