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

Network servers/Minicomputer Serves other computers Using time-sharing tech. ~10 users $50,000 as a server in a small company, school, etc. A high-end network server - The Sun Fire® E25K data center server that uses multiple UltraSPARC IV processors

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 >$1,000,000 used by airline companies, banks, universities, government, HK Jockey Club, etc. IBM® zSeries® 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. The Web site of Cray® - a supercomputer company ( Top500 of supercomputers

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 Input Unit Output Unit Backing store Central Processing Unit (CPU) 中央處理器 Memory ROMRAM **Press Hyperlinks

Central Processing Unit (CPU) Pentium Pentium MMX Pentium II Pentium III P4

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 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 T765

Visual Display Unit - LCD Flat display surface Save space Expensive

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

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

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

BUS A group of wire transmits digital (0/1) signals A group of wire

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

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: X is the secondary memory 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: Y is the output unit Example is visual display unit (VDU)