OSCA TOPIC 1-5.docx - TOPIC 1: INTRODUCTION TO COMPUTER...

TOPIC 1: INTRODUCTION TO COMPUTER OVERVIEW
THE PROCESS CONTROL
STAND-ALONE COMPUTER SYSTEM
Input: keyboard, mouse, scanner, punch cards
Processing: CPU executes the computer program
Output: monitor, printer, fax machine
Storage: hard drive, optical media, diskettes, magnetic tape
COMPUTER SYSTEM
All computer systems, no matter how complex, consists of the following:
1. At least one CPU
2. Memory to hold programs and data.
3. I/O devices
4. Long-term storage
COMPUTER SYSTEM COMPONENTS
1. Hardware
Processes data by executing instructions
Provides input and output
Control input, output and storage components
2. Software
Applications and system software
Instructions tell hardware exactly what tasks to perform and in what order

3. Data
Fundamental representation of facts and observations
4. Communications
Sharing data and processing among different systems
HARDWARE COMPONENTS
1. Input/Output devices
2. Storage Devices
3. CPU – Central Processing Unit
 ALU: arithmetic/logic unit
 CU: control unit
 Interface unit
4. Memory
 Short-term storage for CPU calculations
THE CENTRAL PROCESSING UNIT
1. ALU: arithmetic/logic unit
Performs arithmetic and Boolean logical calculations.
2. CU: control unit
Controls processing of instructions.
Controls movement of data within the CPU
3. Interface unit
Moves instructions and data between the CPU and other hardware components.
Bus : bundle of wires that carry signals and power between different components
MEMORY
Also known as primary storage , working storage , working storage, and RAM (random access memory).
Consists of bits, each of which hold a value of either 0 or 1 (8 bits = 1 byte).
Holds both instructions and data of a computer program ( stored program concept ).

COMMUNICATION COMPONENTS
1. Hardware
 Communication channels
o Physical connections between computer systems
o Examples: wire cable, phone lines, fiber optic cable, infrared light, radio
waves
 Interface hardware
o Handles communication between the computer and the communication
channel.
o Modem or network interface card (NIC)
2. Software
 Establish connections.
 Control flow of data
 Directs data to the proper applications for use.
VIRTUALIZATION
• Virtual (American Heritage Dictionary
– Existing or result in essence or effect though not in actual fact, form, or name.
– Created, simulated, or carried on by means of a computer or computer network.
• Examples
– Virtual memory
– Virtual networks
– Java Virtual Machine
PROTOCOLS
Common ground rules of communication between computers, I/O devices, and many software programs
Examples
 HTTP: between Web servers and Web browsers
 TCP/IP: between computers on the Internet and local area networks
 SATA: between storage devices and computers
 XML, RSS, SIP: new protocols
STANDARDS

A Standard is basically a document containing the details of an agreed upon method.