Chapter 1, Problem 2D

The functional units of the computers are, central processing unit, main memory, secondary memory, input devices and output devices.

The central processing unit:

• The central processing unit is the principal part of the computer. The CPU performs almost every processing inside a computer.
• The CPU is consisting of main memory, control unit and arithmetic-logic unit. The CPU controls all the peripherals of the computer system and it controls the instructions and the data flow to and from all the parts of the computer.
• In modern computers the CPU is contained on an integrated circuit chip called a microprocessor.
• The CPU has two components:
  • Arithmetic Logic Unit (ALU): this part of the CPU handles arithmetic and logic operations.
  • Control Unit: this part of the computer extracts the instructions from the memory and executes them.

Main memory:

The physical memory that internal to the computer system is called as the main memory. The word “main” is used to differentiate the memory from secondary storages like hard disk drive, read-only memory and so on.

• The main memory is also called a Random Access Memory (RAM) or primary memory.
• The main memory stores all the information that the computer currently working on.
• The main memory loads with all the files used to execute a program on the computer. The main memory determines how many programs can be executed at a time...