CS 1 A Typical Computer system A

CS 1 A Typical Computer system

A Typical Computer System • Types of Computers • Components of a Computer System

Types of Computers • Microcomputer • Handheld/Palmtop/PDA • Notebook/Laptop • Desktop • Network servers/Minicomputer • Mainframe • Supercomputer

Microcomputer-Handheld • • • Personal digital Assisant (PDA) Pocket size Application: – – – • • e-appointment book address book Calculator Notepad Telephone/ fax Internet and networking feature (e. g. bluetooth, Infra-red, wi-fi, etc. ) Use touch screen, pen-based handwriting recognition, keypad or voice recognition tech. 200 MIPS (Million instruction per second) Single user $2000

Microcomputer-Notebook • Also called Laptop compute • Features: – Portable – Encasing inside a plastic / metal case • • 5000 MIPS Single user $12, 000 At office or home

Microcomputer-Desktop • • • Non-portable 6000 MIPS Single user $10, 000 At home or office

Microcomputer-Desktop power supply ventilation system ports interface card The system unit of a desktop computer (back view)

Network servers/Minicomputer • • • A high-end network server - The Sun Fire® E 25 K data center server that uses multiple Ultra. SPARC IV processors Serves other computers Using time-sharing tech. ~10 users $50, 000 as a server in a small company, school, etc.

Network servers/Minicomputer A server in a local area network

Network servers/Minicomputer A high-end server (or midrange computer) • can store and distribute huge amount of data • has fault-tolerant features that guarantee uptime Fault-tolerant: • even a part fails, the whole system can still operate • redundant components, such as hard disks, power supplies, are required

Mainframe • Large, fast, powerful and expensive computer • Features: – – – Time-sharing mode Huge main memory Centralised control Highly reliable Strong data security • ~1000 users • >$1, 000 • used by airline companies, banks, universities, government, HK Jockey Club, etc. IBM® z. Series® 990 - enterprise server

Mainframe Multi-user modes • allow multiple users to access the system at the same time • differences between multi-user modes: – In mainframe-based networks • major processes are done by the mainframe’s CPU • dumb terminals have limited processing power – In client/server networks • end user processes are handled by workstations • the major tasks of a server are to provide resources, enforce securities and coordinate among various CPUs

Supercomputer • One of the fastest computers in the world • Handles CPU intensive job • Billion in cost • weather forecast, space research • e. g. blue, deep blue, cray, etc. Top 500 of supercomputers The Web site of Cray® - a supercomputer company (http: //www. cray. com)

Components of a computer system • • • Central Processing Unit (CPU) Memory Input Unit (Device)** Output Unit (Device)** Backing Store ** **Peripheral Device (週邊設備)

Components of a computer system Central Processing Unit (CPU)中央處理器 Memory Input Unit RAM ROM Output Unit Backing store **Press Hyperlinks

Central Processing Unit (CPU) 286 386 486 Pentium MMX Pentium III P 4

CPU • Built on a processor chip (晶片) • Accept and executed instructions stored in main memory • Brain of a computer • Arithmetic Logic Unit (ALU) (calculation) • Control Unit (CU) (give order) • Registers (small storage units inside CPU)

CPU • Clock speed – Measured in MHz or GHz – Number of clock cycles or ticks per second – The higher the clock speed, the faster the computer (∵each instruction is processed in a fixed number of clock cycles) • Cache Memory – Faster memory – Located between the CPU and RAM – Increasing the speed of memory access

Memory (1) • Many names… – Central memory, main store, primary memory, internal memory • • • ROM/ RAM Part of the CPU Access quickly Expensive Limited storage capacity

Memory - It stores. . • • • Information from Input Unit Data for processing Calculated results Processed output Data accessing time fast

Input Unit • Reading of Information • Encoded in input medium • E. g. keyboard, mouse, scanner, etc.

Output Unit • Writing the processed results • to human readable form • Visual Display Unit (VDU) and printer.

Visual Display Unit Compaq TFT 8000 EIZO T 765

Visual Display Unit - LCD • Flat display surface • Save space • Expensive

Backing Store CD ROM Hard Disk Magnetic Tape • Also called Secondary memory • Permanent(? ? ? ) storage • Larger capacity • Lower cost • But slower speed

Backing store consists of. . . • Storage Media • Storage Device • Other example. . Media Device

Ports and Interface cards • Ports – Built on the motherboard – Interface between peripheral devices and memory – Connect directly to Peripheral buses • Interface cards – Circuit board that connects a peripheral device to the motherboard – Inserted into Interface slots which are built on the motherboard – Connect directly to Peripheral buses

Ports and Interface cards

Ports and Interface cards

BUS • A group of wire transmits digital (0/1) signals 0 1 2 3 4 5 6 7 01010101010101010 0101010101010101 101001010010101010 A group of wire

How bus control? CPU ALU Input unit CU Memory Data bus Control bus Backing Store Output unit

Three types of BUS • Control BUS • Data BUS • Address BUS

Control BUS • Carry control signals • Signal like control memory Read/Write, • Control peripheral access • Control all execution

Data BUS • Carry Data signals through different Units • Bi-directional • Data transmit in parallel

Address BUS • Carry Address signals • In need when you want to read/write from memory

Exercise • (a) Write down the name of the component represented by box X. Name one device which is an example of this component. • Soln: ü X is the secondary memory ü Example is Hard disk

Exercise • (b) Write down the name of the component represented by box Y. Name one device which is an example of this component. • Soln: ü Y is the output unit ü Example is visual display unit (VDU)