pstree shows lots of process

Question

This is a dump of pstree. I am running firefox (one tab) and gnome-terminal (1 tab). I count 4 gnome-terminal processes and 34 firefox processes. Is it normal? Actually every application running seems to be duplicated. Thanks

init─┬─NetworkManager─┬─dhclient
     │                ├─dnsmasq
     │                └─3*[{NetworkManager}]
     ├─accounts-daemon───2*[{accounts-daemon}]
     ├─acpid
     ├─at-spi-bus-laun─┬─dbus-daemon
     │                 └─3*[{at-spi-bus-laun}]
     ├─at-spi2-registr───{at-spi2-registr}
     ├─atd
     ├─avahi-daemon───avahi-daemon
     ├─bamfdaemon───3*[{bamfdaemon}]
     ├─bluetoothd
     ├─colord───{colord}
     ├─console-kit-dae───64*[{console-kit-dae}]
     ├─cron
     ├─cups-browsed
     ├─cupsd───dbus
     ├─2*[dbus-daemon]
     ├─dbus-launch
     ├─dconf-service───2*[{dconf-service}]
     ├─evolution-calen───4*[{evolution-calen}]
     ├─evolution-sourc───2*[{evolution-sourc}]
     ├─firefox───34*[{firefox}]
     ├─gconfd-2
     ├─gdm─┬─gdm-simple-slav─┬─Xorg───2*[{Xorg}]
     │     │                 ├─gdm-session-wor─┬─gnome-session─┬─compiz─┬─sh───+
     │     │                 │                 │               │        └─3*[{c+
     │     │                 │                 │               ├─deja-dup-monit+
     │     │                 │                 │               ├─evolution-alar+
     │     │                 │                 │               ├─gnome-fallback+
     │     │                 │                 │               ├─gnome-screensa+
     │     │                 │                 │               ├─gnome-settings+
     │     │                 │                 │               ├─gnome-user-sha+
     │     │                 │                 │               ├─polkit-gnome-a+
     │     │                 │                 │               ├─ssh-agent
     │     │                 │                 │               ├─telepathy-indi+
     │     │                 │                 │               ├─tracker-miner-+
     │     │                 │                 │               ├─tracker-store─+++
     │     │                 │                 │               ├─update-notifie+
     │     │                 │                 │               ├─zeitgeist-data+
     │     │                 │                 │               └─3*[{gnome-sess+
     │     │                 │                 └─2*[{gdm-session-wor}]
     │     │                 └─2*[{gdm-simple-slav}]
     │     └─2*[{gdm}]
     ├─5*[getty]
     ├─gnome-keyring-d───7*[{gnome-keyring-d}]
     ├─gnome-terminal─┬─gnome-pty-helpe
     │                ├─tcsh───pstree
     │                └─3*[{gnome-terminal}]
     ├─goa-daemon───2*[{goa-daemon}]
     ├─gvfs-afc-volume───2*[{gvfs-afc-volume}]
     ├─gvfs-gphoto2-vo───{gvfs-gphoto2-vo}
     ├─gvfs-mtp-volume───{gvfs-mtp-volume}
     ├─gvfs-udisks2-vo───{gvfs-udisks2-vo}
     ├─gvfsd───{gvfsd}
     ├─gvfsd-burn───{gvfsd-burn}
     ├─gvfsd-fuse───4*[{gvfsd-fuse}]
     ├─gvfsd-trash───2*[{gvfsd-trash}]
     ├─hud-service───3*[{hud-service}]
     ├─indicator-appli───{indicator-appli}
     ├─indicator-bluet───2*[{indicator-bluet}]
     ├─indicator-datet───3*[{indicator-datet}]
     ├─indicator-messa───2*[{indicator-messa}]
     ├─indicator-print───2*[{indicator-print}]
     ├─indicator-sessi───2*[{indicator-sessi}]
     ├─indicator-sound───2*[{indicator-sound}]
     ├─indicator-sync-───{indicator-sync-}
     ├─irqbalance
     ├─login───tcsh
     ├─mission-control───2*[{mission-control}]
     ├─modem-manager
     ├─polkitd───{polkitd}
     ├─pulseaudio─┬─gconf-helper
     │            └─2*[{pulseaudio}]
     ├─rsyslogd───3*[{rsyslogd}]
     ├─rtkit-daemon───2*[{rtkit-daemon}]
     ├─ubuntuone-syncd───3*[{ubuntuone-syncd}]
     ├─udevd───2*[udevd]
     ├─udisksd───4*[{udisksd}]
     ├─unity-applicati───2*[{unity-applicati}]
     ├─unity-files-dae───2*[{unity-files-dae}]
     ├─unity-lens-frie───2*[{unity-lens-frie}]
     ├─unity-lens-phot───3*[{unity-lens-phot}]
     ├─unity-music-dae───{unity-music-dae}
     ├─unity-musicstor───2*[{unity-musicstor}]
     ├─unity-panel-ser───3*[{unity-panel-ser}]
     ├─unity-scope-gdr───3*[{unity-scope-gdr}]
     ├─unity-scope-vid───2*[{unity-scope-vid}]
     ├─unity-video-len───{unity-video-len}
     ├─unity-webapps-s───2*[{unity-webapps-s}]
     ├─upowerd───2*[{upowerd}]
     ├─upstart-file-br
     ├─upstart-socket-
     ├─upstart-udev-br
     ├─vsftpd
     ├─whoopsie───2*[{whoopsie}]
     ├─wpa_supplicant
     ├─zeitgeist-daemo───{zeitgeist-daemo}
     └─zeitgeist-fts─┬─cat
                     └─{zeitgeist-fts}

Answer 1

Those are threads. If you read man pstree you will see the following part:

Child threads of a process are found under the parent process and are shown with the process name in curly braces, e.g.

       icecast2---13*[{icecast2}]

Which is comparable with what you see:

       firefox───34*[{firefox}]

So, nothing to worry about.

Answer 2

Yes, it is normal. A lot of programs use more than one process, therefore there is nothing to worry about.

The reason for this is programs like Google Chrome/Chromium or I.E. divide the programs functions such as rendering individual tabs into multiple processes to increase the efficiency of use across multiple processor cores and threads allowing for better performance.

Other programs do this as well do delegate program tasks across multiple processor cores or threads if the program has the possibility of causing too much strain on a single thread/core.

Source:http://www.liutilities.com/articles/what-are-computer-processes/#.UwaXgvldV1Y http://www.qnx.com/developers/docs/6.4.1/neutrino/getting_started/s1_procs.html

I hope this helps.