CS 104 Introduction to Computer Science and Graphics Problems Basic Organization & Concepts 09/09/2008 Yang Song (Prepared by Yang Song and Suresh Solaimuthu)

Basic Computer Operations Input Storage Processing Control Output

Input Process of entering data and instructions (program) into the computer system. As any other machine, computer takes inputs, process it, giving out processed data.

Storage The process of saving data and instructions PERMANENTLY. Data has to be fed into the system BEFORE the actual processing starts. Why? CPU v.s. I/O.

Processing Performing operations Arithmetic Logical The Central Processing Unit (CPU) takes data and instructions from storage unit and makes all sorts of calculations based on the instructions given and the type of data provided

Control The manner how instructions are executed and the previous operations are performed. Manage all the operations: input, output, processing… Take care of step by step processing of all operations inside the computer

Output The process of displaying results from the data and instructions for getting useful information

Block Diagram of a Computer System

Input Unit Gives input data to CPU Device: keyboard, mouse… and?

Output Unit Displays the results from the CPU Device: monitor, printer… and?

Input/Output Devices The devices that acts as both the input and output units Such as?

Processing Unit Central Processing Unit (CPU) Brain of the computer Arithmetic/Logic Unit (ALU) Control Unit (CU) Memory Unit (MU) Internal storage Temporary storage

Arithmetic/Logic Unit (ALU) Numeric operation Addition, subtraction Maybe multiplication Logical operations AND, OR, NOT, XOR Bit shift operations Multiplication/Division by 2 Decides which side the bit is shifted

Control Unit (CU) Controls the entire operations of a computer Interprets the instruction and controls flow of execution Sends signal to ALU about what operation is to be done Sends signal to MU about which data/instruction to be transferred, if the data has to be saved or deleted

Memory Unit (MU) Stores several different types of data Numbers – integers, reals… Characters – alphabetic, punctuation, special symbols Logical data – True/False results Instructions All have address RAM / ROM

Storage Memory Unit is the primary fast, volatile, store current using instruction/data Storage unit is the secondary slow, permanent, store for future use or archive peripheral device device: hard disk, floppy disk… and?

Memory Hierarchy

Peripheral Devices Any device attached to a computer in order to expand its functionality Input Devices Output Devices Storage Devices Also include other computers on a network system