THE COMPUTER

A computer is defined as an electronic device, which accepts, processes and store data for later use or sends out data as information.

TYPES

• embedded

• mobile computer

• Personal computer

• mainframe Computer

• Supercomputer

ADVANTAGES OF USING A COMPUTER

• Consistency and accuracy of the results provided

• Enhanced storage

DISADVANTAGES OF USING A COMPUTER

• the initial set up cost is high

• easier for security and integrity of data to be compromised

HARDWARE

Hardware is any part of the computer that has physical structure, including the computer’s internal parts.

All computer systems need hardware to carry out the following four main processes:

• Accepting Input

• Processing that Input

• Producing output information

• Storing data and/or information for later retrieval and use

NOTE

• Input- The act of accepting data form the outside world

  Input device - a device responsible for getting data into a computer

• Processing- The act of transforming data into information that will be useful to the user

• Output- The act of presenting information to the user

  Output device- get processed data out of the computer

• Storage- The act of holding data, program instructions & information for later use.

• Memory enables a computer to temporarily store instructions and data

THE CENTRAL PROCESSING UNIT (CPU)

This is the brain of the computer it manages and orchestrates how the computer functions it consists of the CU & ALU

CU - executes software instructions and guides data flow

ALU- responsible for all calculations and logical operations

!!Peripheral devices- located outside the CPU but controlled by it.!!

WHAT IS PRIMARY STORAGE?

This is the component of the computer that holds data, programs and instructions that are currently being used.

WHAT IS SECONDARY STORAGE?

Secondary storage includes non-volatile devices for storing data outside of a computer's main memory (RAM).

MAIN MEMORY

RAM (random access memory)

a type of computer memory that serves as the short-term working memory of a computer

• Dynamic RAM

• Static RAM

CHARACTERISTICS

• Volatile (data is lost when power is lost)

• Larger in Capacity

• Temporary

• Faster and expensive

ROM (Read Only Memory)

• PROM-Can only be modified ONCE by the user

• EPROM-Data can be erased using ultraviolet rays and can be reprogrammed

• EEPROM- Data can be erased and reprogrammed repeatedly by applying an electrical voltage that is higher than normal. (over 10k times)

CHARACTERISTICS

• Non-volatile (data is lost when power is lost)

  Small Capacity

• Slower but cheaper

WHAT IS STORAGE UNIT?

A unit of measure used to show how much info can be saved and kept on a computer.

• 8 bits = 1 byte

• 1024 bytes= 1 kilobyte

• Nibble = ½ a byte

CLOUD STORAGE

• The process of storing data in an online space that spans multiple servers and locations, and it is usually maintained by a hosting company.

• People pay these companies to keep their data on servers and give them access to it anytime once they have internet connection.

• Examples: Google drive and Icloud

LOCAL STORAGE

• the process of storing digital data on physical storage devices (hard disk drives and external storage devices)

SOFTWARE

Software is a program that is executed by the hardware of the computer

TYPES - System software Application programs

SYSTEM SOFTWARE- used to operate and maintain a computer system includes the

• operating system

• utility programs

• language translators

OPEERATING SYSTEMS

• A set of programs that governs the operation of the computer.

• 6 primary functions (usfrmp)

  • User Interface- This is the point at which human user interact with a computer.

    • Types of user interface

      • Graphic user interface

      • Hardware interface

      • Software interface

      • Command driven

      • Menu-driven interface

  • Security Management- maintains a secure computing environment.

  • File Management - manages files and folders.

  • Resource Management- manages storage devices, input & output devices.

  • Memory Management- manages memory.

  • Process Management- manage processor resources.

• Examples are MacOS, IOS, Windows

SYSTEM UTILITY

• a specialized program that assists in maintaining and improving the efficiency of a computer system.

  • Back up

  • Defragmenter - reorganize

  • Disc error checker

  • Disc cleanup

  • Antivirus

  APPLICATION SOFTWARE NEEDS TOUCH UP

• Programs that help the user perform specific ask

• GENERAL PURPOSE: These are software that are not specific to anyone organization or business and can be used by anybody. For e.g.: Word, database, PowerPoint, Canva

• Customized software: general purpose software that has been modified to perform specific task for user.

• Custom Written: Also known as TaylorMade is written for use in specific organization.

• SPECIALIZED SOFTWARE: This is software that is designed for specific need or task. For e.g.: A camera on your device

DATA

• Raw unprocessed facts

  • Raw facts

  • no context

  • Plain numbers, text, etc.

INFORMATION

• meaningful knowledge derived from raw data.

• Data that has been processed/organized in a useful way

  • Processed data

  • data with context

  2 types of sources

• Thing that has been measured eg temperature | 28

• Person or organization that provided the data from observation.

Source documents are documents that contains data for input into an information processing system.

• Human-Readable Document

  • This is a document that can be read naturally by humans. It is not in a form that the computer can readily accept.

• Machine-Readable Document

  • This is one that can be readily process be the computer. E.g. items within barcode

• Turn-Around Document

  • This is a computer-generated form that is fill out, sent out and returned to the computer.

VERIFICATION

This is double checking for error with data that has already been entered.

Good verification significantly reduces the number of

• Typographical errors (missing or extra letters)

• Transposition errors (switching the position of 2 adjacent characters in a text)

Type of verification

• Proofreading- a data entry clerk visually checks the source document against data that has already been input by another entry clerk.

• Double data entry- when data is entered twice for comparison.

Validation

A checking process in a program which is aimed at finding out if the data entered is genuine

Type of validation

• Data type check

• Presences checks

• Check digit.

• Range check

• Consistency check

• Length check

• Reasonableness check

• Format check