Download - Computer System Review
Computer Science
ICS3M - Unit 1
CentralProcessing
Unit
Memory
RAMROM
Input Devices
Output Devices
SecondaryStorageDevices
Computer Hardware Functions
I/O Devices
Examples of input devices:– keyboard– optical character reader– microphone
Examples of output devices:– video screen– printer– loudspeaker
Ports and Connectors
Port are catagorized by their mode of transmission:– Parallel port
Standard parallel port (printers) Small Computer System Interface (SCSI)
– Serial port Standard serial port (modem, mouse) Musical instrument digital interface (MIDI) Universal Serial Bus (USB)
Connectors– Male have one or more pins– Female have locators that match the pins on the male
Storage
Hard Drive Floppy Drives CD-ROM DVD R-CD-ROM RW-CD-ROM Zip Drives
Disk Capacities
Floppy: 1.4 MB Hard disk: 20 GB – 160 GB
CD 700 - 800 MB
DVD 4.7 GB - 17 GB
1 BYTE = 1 CHARACTER1 KILOBYTE = 1000 BYTES1 MEGABYTE = 1000 KB or 1,000,000 KILOBYTES1 GIGABYTE = 1000 MB or 1,000,000,000 KILOBYTES
Magnetic Disk Storage
Disk Fragmentation
Fragmented disk shows spaces where data has been removed
Defragmenting has placed all files in contiguous spaces
Defragmenting a drive will increase efficiency for file retrieval
CD-ROM and Optical Disks
CD-ROM (compact disk ROM)– 650 MB of information
DVD-ROM (digital versatile disk)– 4.7 gigabytes
CD-R (compact disk-recordable) Magneto-optical (MO)
– 230 MB, 650 MB, 1.3 GB– supports read and write operation.
Memory
RAM = Random Access Memory– The space available to a computer to use while
performing operations. The space is emptied out when the computer is turned off.
ROM = Read Only Memory– The memory programmed by the manufacturer
containing system information.– Cannot be overwritten without special software.
Computer Units
Quantity/size/capacity– Kilo byte -- KB
one KB is 1024 (210) – Mega byte -- MB
one MB is 1024KB = 1024x1024 (220) e.g., 4096MB = 4MB
– Giga byte -- GBone GB is 1024MB = 1024x1024x1024 (230)
– Tera byte -- TBone TB is 1024GB = 1024x1024x1024x1024 (240)
Operating Systems
The operating system acts as the interface between the application and the computer system
The following are examples of operating systems.– Microsoft Windows, Unix, Linux, and Macintosh
Operating System Software
Role of Operating System Software is to:– perform common computer hardware functions– provide a user interface– manage system memory– manage processing tasks– provide networking capability– control access to system resources– manage files
Application Software
Application software consists of programs designed to perform specific tasks or applications.
Examples include, such as– Word processing programs– Spreadsheet programs– Database programs– Presentation programs– E-mail programs– Web browser programs
Networking
A network is defined as two or more computers connected together
– Peer-to-peer when a server is not involved.– Client-server when a server is involved.
Uses and Benefits of a LAN– Security through id and password– Shared peripherals– Shared storage– Shared Applications– Reliability and Resilience– centralized backup systems for data recovery– centralized virus protection
Conclusion
Hardware devices work together to perform input, processing, data storage, and output.
Networks allow computers to share information and resources.
There are two main categories of software: systems software and application software.
An operating system (OS) is a set of computer programs that controls the computer hardware to support users’ computing needs.