memory requirement to install linux
 

Hi, I have dell inspiron 1545 laptop. How can i install linux in it and how much space should i give in hard disk for linux installation?

welcome to lq
the answer to that depends on how much you are going to install, linux can be configured to fit on a floppy (albeit very speciallized) to upwards of 6-10 gigs installed, but on average i would say about 4-8 gigs for the os and programs minimum plus the size of your ram for swap space, a minimum of 256-512MB ram then youll want free space for data files and any additional software etc..

Linux ~USUALLY~ needs atleast 512M RAM but varies by distribution.

Most distro's offer a minimum hardware list that helps. The gui is the main resource hog.

By the way you can run a virtual machine (most likely) on that system too if you don't want to bother with a dual boot. VM's have easy ways to allocate resources and you can run both OS's at the same time.