[linux-audio-user] minimum requirement for a real-time FX processing machine

Hi everybody, first of all thanks for your answers to my previous posts. Now that I'm having fun playing around with a bass guitar and ecasound, I'm thinking about buying an old laptop to use during rehersals and maybe gigs. I'm wondering what kind of hardware would do the trick. I'm kind of broke so the older (i.e. cheaper) the better (it would just run a shell, a tweaked kernel, JACK and FX processing stuff). I guess I may run into problems with obsolete sound cards (an area I'm not much knowledgeable in) and probably other issues I don't know about yet... Anybody has any experience/knowledge to share ? What would be the absolute minimum requirement for you ? btw, I'm also wondering about vibrations damaging the hardware, particularly the HD (the box would sit on top of a bass amp, or at least not so far from it) What do you think about it ? Thanks for taking the time to read this.