Installing Music Applications On Hard Disc?, Can it be done? Options

[Foxyphil]

Hardware - emac G4 running osX10.47. 1.25Ghz. Carillion Firewire Hard Drive 300 Gb. Focusrite Saffire.

Sequencers. Logic Express 7.2. Cubase l.e.

In a nutshell< Im quickly running out of disk space on my emac - and have about 12 Gb left. Any software I have purchased has not, to my knowledge, offered me the option of installing on the hard drive. I was wondering if I could install OSX10.4 - Tiger - onto the external firewire hard drive - and would this then enable me to install applications directly onto the external drive?

Sorry if this is a silly question.

Any feedback gratefully received .

Many thanks

Phil