View Chapter_3_Relations_and_Functions_Part_2.pdf from COMPUTER S 123 at KDU University College. XBCS1103 DISCRETE MATHEMATICS Chapter 3: Relations and Functions Part 2 Hemavathi Ramulu Department of. ... Chapter_3_Relations_and_Functions_Part_2.pdf - XBCS1103 DISCRETE MATHEMATICS Chapter 3:. 1) SYSTEM UNIT/COMPUTER CASING. This box is where all the main computer components are housed - Motherboard, processor, memory, hard disks, power supply, and more. Computer casings come in all shapes and sizes, with the common ones being tower casings (as above), and small form factors that fit in a backpack.