Computer System電腦系統

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Software軟件

System Software系統軟件

System sofware refers to programs which make your computer works.

Operating System操作系統

Functions:1. allocate system resource2. manage files3. monitor activites

example

Windows

Apple OSX

Linux

types

single tasking

be able to handle ONE task at a particular time.

multi tasking

be able to handle multiple tasks at the same time.

single user

only one user can use the computer at a particular time.

multi user

several users can be using the same computer or even the same program on that computer at the same time.

User Interface用戶介面

Command Line Interface (CLI)

1. need less system resource2. difficult to learn and master3. works faster

Graphical User Interface (GUI)

1. easier to learn and master2. consume a lot more system resource3. works slower

Utility Program實用軟件

programs to maintain your computer's health and improve the computers performance.

examples

Anti-virus

Disk Defragmentation

Data Compression

Data Recovery

Encryption

System optimizer

Screen Saver

Driver 驅動程式

programs which helps an OS to communicate and manage a peripheral device.

Application Software應用軟件

Application software refers to programs that help users get their works done by using the computer. The list is only a small sample.

Word Processing

Database (DBMS)

Spreadsheet

Presentation

Graphics

Sound editing

Communication

Hardware硬件

System Unit

CPU

Control Unit

Arithmetic Logical Unit

cache快取記憶體

fast memory unit located inside CPU to store frequently used instructions and data for the CPU. Compare to RAM, it is1. faster2. small in capacity 容量較RAM少 (usually measure in MB)3. more expensive

performance factor

clock speed時鐘頻率

Hz

1 instruction cycle

the faster the better

e.g. 2.8GHz

2.8GHz means in a second there are 2.8 billion instruction cycles.

word length字長

It means the number of data that can be processed at one time. Usually measured in bits, for example, 16-bit, 32-bit and 64-bit.

Motherboard

slots

bus 總線

ports 連接埠

USB

PS2

LAN

VGA

DVI

Main memory

RAM

1. volatile - loss data when power off2. store temporary data and instructions to be used by CPU3. upgrade - memory capacity can be changed

ROM

stores:1. S (Basic Input Output System) - a program to be loaded into RAM for checking the computer hardware configuration2. Boot program - a program to start the computerCharacteristics:1. store permanent instruction2. read ony / can't be written3. small in capacity4. non-volatile

CMOS

1. non-volatile2. store system information (e.g. date, harddisk info, RAM info etc)3. data inside it can be updated/ changed.

Peripherals週邊設備

devices other than the system unit

input devices

pointing

mouse

touch pad

track ball

biometrics

the use of personal characteristics / features to identify a computer user. In that way, people don't need to remember their computer passwords as they use their body traits as passwords.

finger print

iris recognition

scanner

barcode reader

output devices

monitor

resolution

The number of pixels can be displayed. There are many standards, for example , VGA, SVGA, XGA etc.

color depth

Number of colors can be displayed. Usually measured in bit. For example, 4-bit color means 2^4 = 16 colors.

pixel

speaker

printer

dpi (dot per inch) - quality

ppm (page per minute) - speed

storage devices

secondary storage

storage devices which are not the main memory all fall into this category.

magnetic

floppy

harddisk

The major secondary storage device.

magnetic tape

Mainly for server backup.

optical

CD

DVD

semi-conductor

flash memory card

CF

SD

Memory Stick

xD

USB thumb drive

units

bit

the smallest / basic computer storage unit. It stores eithe a 0 or a 1.

byte - 8 bits

KB

MB

GB

processing

display / graphic card

sound card

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