computer applications notes grade 6

Computer Applications

Grade 6

3 Types of Computers:

Main Frame

a) Largest

b) Most Expensive

c) Stores the Most Data

Minicomputer

a) 2nd Largest

b) 2nd Most Expensive

c) 2nd in Storing Data

Microcomputer

a) Smallest

b) Least Expensive

c) Stores Least Amount of Data

Electrical Signals:

Digital – Uses On or Off electrical signals.

Analog – Uses a smooth continuous change in the electrical signal.

4 Parts of the Computer:

Input – Enters data into the computerOutput – Returns processed dataMemory – Stores dataCentral Processing Unit (CPU) – The

brain or the heart of the computer

Memory: Random Access Memory (RAM)1) Memory that we use when we are using the

computer

2) Can be changed

3) Temporary

Read Only Memory (ROM)1) Memory that the computer uses

2) Can Not be changed

3) Permanent

Central Processing Unit:

Made up of the following two units:1. Control Unit – directs the flow of the

program or data.

2. Arithmetic Logic Unit (ALU) – all math and comparing is done here.

4 Parts of the Computer:MEMORY

INPUT

CPU

OUTPUTCONTROL

ALU

Inside the Computer:Computer Chip – thin wafer of silicon

that is an 1/8th of an inch square. Integrated Circuit Chips (ICC) –

integrated electrical circuits on the tiny computer chips.

Large Scale Integration (LSI)

Process of making a computer chip:

1) A design is made.

2) The design is photographed and reduced to chip size.

3) Photograph is “baked” on the silicon.

4) The chip is magnetized.

5) The chip is tested and placed in protective casing.

Computer Definitions: Bit (binary digit) – tiny electrical signal. If

the signal is On = 1 and if the signal is Off = 0.

Byte – Pattern of 8 electrical signals or 8 bits. Everything on the keyboard has its own pattern.

Nybble – ½ a byte. Memory Size:a) 1 Kilobyte (K) – 1024 bytesb) 1 Megabyte (meg) – 1024 Kilobytesc) 1 Gigabyte (gig)–1024 megabytesd) 1 Terabyte (TB)–1024 gigabytes1 Gigabyte = approx 500,000 letter-size pages of text information

More Definitions: Computer Hardware – Any part of the computer

(monitor, disk drive, speakers, printer…). Computer Software – Programs used on the

computer (Microsoft Word, Power Point, Sim City, LOGO…..).

Binary Code – Base 2 number system made up of 1’s and 0’s.

ASCII Code – Each character on the computer has it’s own code number.

(See the chart on the next slide).Don’t write this in your notes!

ASCII Chart: