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.