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.