Hi,

Books for the GATE 

Computer Science and Information Technology

Engineering Mathematics - Discrete Mathematics and Its Applications by Kenneth Rosen

Digital Design - Morris Mano

Programming - Dennis Richie

Data Structures and Algorithms - Cormen

Theory of Computation - Peter Linz

Computer Networks - Kurose & Ross

Computer Organization and Architecture - Carl Hamacher

Operating System - Galvin

Databases - Korth