Computer memory

 From:  diamond geyser (DAVIDWREFORD)
6420.1 
I'm a newbie (to CAD in general) and have no doubt I'll be a MoI user soon. I need a laptop first. Can someone advise on the memory capacity I need (RAM and hard drive)? As far as hard drive is concerned I'd value an indication of the file size of a design.....a fairly basic design.

Tx, DW