2. 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
3. Electrical Signals:
Digital – Uses On or Off electrical
signals.
Analog – Uses a smooth continuous
change in the electrical signal.
4. 4 Parts of the Computer:
Input – Enters data into the computer
Output – Returns processed data
Memory – Stores data
Central Processing Unit (CPU) – The
brain or the heart of the computer
5. 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
6. 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.
7. 4 Parts of the Computer:
MEMORY
INPUT
CPU
OUTPUTCONTROL
ALU
8. 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.
9. 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.
10. 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 bytes
b) 1 Megabyte (meg) – 1024 Kilobytes
c) 1 Gigabyte (gig)–1024 megabytes
d) 1 Terabyte (TB)–1024 gigabytes
1 Gigabyte = approx 500,000 letter-size pages of text information
11. 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!
