Overview
of a Computer System
Hardware, Software,
and People
Some Basic Terms
- Hardware - the equipment associated with a computer
system
- Software - the instructions that tell a computer what
to do
- Applications Software - software that is used to solve a particular
problem
- Program - set of step-by-step instructions that directs
the computer
- Computer Programmer - person who writes programs
- User - people who purchase and use computer software
- The equipment associated with a computer system
- A computer is a machine that accepts data (input) and processes it into
useful information (output).
- Input Devices accept data in a form the computer can
use.
- The Central Processing Unit (CPU) has the electronic circuitry for
manipulating input into the information wanted.
- Memory temporarily holds data and instructions needed
by the CPU.
- Output Devices make the processed data available for
use.
- Secondary Storage Devices store additional data and
programs.
- Typing on a keyboard
- Pointing with a mouse
- Writing with a pen-based computer system
- Speaking to a voice input system
- Scanning with wand readers, bar code readers, and scanners.
- The CPU is responsible for transforming raw data into processed
information.
- The CPU consists of electronic circuits that interpret and execute program
instructions, as well as communicate with the input, output, and storage
devices.
- Memory or primary storage holds data input to the system, both before and
after it is processed. It also holds the programs
needed by the CPU.
- Screens can produce lines of written or numerical data and / or color graphics
displays.
- Printers produce printed materials under the control of a
computer program.
- Additional storage separate from the CPU and memory
- Magnetic disk - oxide-coated disk - can be a diskette or hard
disk.
- Magnetic tape - comes on a reel or catridge.
- CD-ROM, compact disc read-only memory optical storage.
- Hardware devices attached to a computer are called peripheral
equipment.
- With personal computers, some peripherals may be built into the same physical
unit.
- In large computer systems, the input, processing, output, and storage functions
may be in separate rooms, buildings, or
even separate countries.
- Mainframes and Supercomputers
- Minicomputers
- Personal Computers and Workstations
- Capable of processing large amounts of data at very high speeds
- Large, expensive over $1M.
- Smaller, slower and less costly than mainframes.
- Used by many small businesses.
- Small, inexpensive - $500 - $5000.
- Used for business and home use.
- High performance workstations are often used for scientific and engineering
work.
- Distinction between PCs and workstations becoming hazy as PCs become more
powerful.
- The process of exchanging data over communications facilities.
- Computer networks that connect computers and their resources are becoming
more widespread.
- A network that connects computers in one location is called a local area
network (LAN).
- Packaged software for PCs usually comes on diskette or CD-ROM for installation
on the hard drive.
- "User friendly" software can be learned with a minimum
of training.
- Word processing / desktop publishing lets you create, edit, format,
store, print text and graphics in a document.
- Electronic spreadsheets organize business data into rows and columns
for analysis.
- Database management programs allow users to manage large collections
of interrelated data.
- Graphics packages display information in visual forms: maps, charts,
and visual presentations.
- Data communications software allows for accessing remote computers
via phone lines.
- Programs are written in a variety of programming languages.
- Some languages are very English-like (high level) while others are more
difficult to follow (low level).
- The Management Information Systems (MIS), or Computing
Services, or Information Services department is usually responsible
for computer resources within an organization.
- Data entry operators prepare data for processing.
- Computer programmers design, write, test, implement, update, and
maintain the programs that process data.
- Systems analysts plan and design computer systems.
- The chief information officer (CIO) oversees the MIS department
and is responsible for the technological goals and operations of the entire
organization.