As you have asked about the books for the preparation of the Centre for Development of Advanced Computing (CDAC) Common Admission test, I am mentioning them, check below for the details

Digital Design

A systematic Approach to Digital design- Fletcher (Prentice Hall)
Digital Logic and Computer Design -Morris Manor (Prentice Hall)

Computer Architecture

Computer Architecture-John Hayes
Computer Organization by Hamacher, Zaky -(Mcgraw Hill)

Title: Microprocessors and Interfacing
Author: Douglas V Hall
Publisher: TMH

Title: Data & Computer Communication
Author: William Stallings
Publisher: PHI

Title: Data Structures
Author: Lipschutz and Seymour
Publisher: Schaum Series

Title: Operating System Concepts
Author: Silbeschatz and Galvin
Publisher: John Wiley & Sons