Learning Computers-Class V
Chapter 1 - Evolution of Computers
Early calculating devices are as follows
· Abacus was the first calculating device. It was
invented by the Chinese about 5000 years ago.
· Pascaline was invented by Blaise Pascal in
1642.It could do addition and subtraction but not multiplication and division.
It is also known as Pascal’s Adding Machine.
· Napier bones was designed by John Napier to
perform multiplication and division.
· Leibnitz’s calculator was improved upon Pascal’s
Adding machine.
· Jacquard’s loom was designed to use punched
cards to control a sequence of operations. Invented by Joseph Marie Jacquard.
· Difference Engine was invented by Charles
Babbage in 1823. It was the first mechanical computer.
· Analytical Engine was an improved version of
Difference Engine. Its concept was based upon today’s computer.
· Charles Babbage is known as “Father of
Computer”. He evolved the concept of a programmable computer.
· Computer development has been categorized into
different generations.
Generation
|
Year
|
Development
|
Examples
|
First Generation
|
1949-1956
|
Vacuum Tubes
|
UNIVAC I and ENIAC
|
Second Generation
|
1956-1963
|
Transistors
|
IBM 1401
|
Third Generation
|
1964-1971
|
Integrated Circuits
|
IBM 360 and Apple 2c
|
Fourth Generation
|
1971-present
|
LSI and Microprocessor
|
Intel 4004 and Intel 8080
|
Fifth Generation
|
Future
|
Artificial Intelligence
|
A Robot
|
·
The different types of computers are:
a) Supercomputers (They have a very large
storage capacity and high processing speeds.)
b) Mainframe Computers (They are less
powerful and less expensive than super computer)
c) Minicomputers (They are general purpose
computers where a large number of people can work together)
d) Personal Computers ( A micro or
Personal computer is the least expensive of all and used at home or for
business purpose)
UNIVAC Universal
Automatic Computer
ENIAC Electronic Numerical Integrator
and Computer
IC Integrated
Circuit
LSI Large
Scale Integration
VLSI Very
Large Scale Integration
Chapter 2 – Computer Memory
The capacity of a computer to store data and information
is called its memory.
When you give instructions to the computer, these
instructions get converted into a new language known as machine language.
The computer only understands language 0’s and 1’s.
The digits 0 and 1 are known as binary digits or bits.
The computer’s memory is measured in a byte. A byte consists of
a group of 8 bits.
1 Byte = 8 bits
1 Nibble = 4 bits
1 Kilobyte = 1024 bytes
1 Megabyte = 1024 Kilobytes
1 Gigabyte = 1024
Megabytes
1 Terabyte = 1024
Gigabytes
The computer memory is of two types
(a)
Primary memory
(b) Secondary memory
Primary memory
or Internal memory stores data and
programs currently in use.
Primary memory is of two types: ROM and RAM.
ROM or Read Only Memory is a permanent non-volatile memory.
RAM or Random Access Memory is a temporary volatile memory.
Secondary memory or
External memory stores data and
programs permanently for future use.
Secondary memory includes.
Hard disk has a storage capacity of 40GB to 550GB.
CD-ROM has a storage capacity of 700MB.
DVD has a storage capacity of 4.7GB to 17GB.
Pen Drive has the storage capacity ranging from 2GB to
32GB.
Floppy disk has a storage capacity of 1.44MB.
Bit is a single-digit having the value
either 0 or 1.
Byte is a group of 8 bits.
ROM Read-Only Memory
RAM Random Access Memory
CD-R Compact Disk Recordable
CD-RW Compact Disk Rewritable
DVD Digital Versatile Disk
Chapter 3 - More on LOGO Primitives
PENUP or PU
command tells the turtle to pick up its pen.
PENDOWN or PD command
tells the turtle to put its pen down.
PENEREASE or PE
command is used to erase the incorrect lines drawn by the turtle.
PENPAINT or PPT
command is used to tell the turtle to start its drawing again.
SHOW command
is used to display the text, number, etc. in the commander window.
SHOW LOWERCASE
command is used to display the text in small letters.
SHOW UPPERCASE command
is used to display the text in capital letters.
SHOW COUNT command
is used to display the total number of letters in a word.
SHOW TIME
command is used to display the current date and time in a list.
REPEAT command
is used to reduce your task of writing the same commands again and again.
Example:-
Drawing a SQUARE using
REPEAT command
REPEAT (number of sides) [FD
(length of each side) RT (Degree of
angles/number of sides)]
or REPEAT 4 [FD
50 RT 90]
Drawing a CIRCLE
REPEAT 72 [FD
5 RT 360/72] or REPEAT 72 [FD 5 RT 5]
Drawing a Semi Circle
REPEAT 180
[FD 1 RT 1] or REPEAT 180 [FD 1 LT 1]
Drawing the letter “S”
REPEAT 180 [FD
1 LT 1]
REPEAT 90 [FD
1 LT 1]
REPEAT 90 [FD
1 RT 1]
REPEAT 180
[FD 1 RT 1]
SETSCREENCOLOR sets
the color of the drawing area with the specified color.
SETSCREENCOLOR
[255 0 0] or SETSCREENCOLOR 4
SETPENCOLOR command
is used to change the color of the pen.
SETPENCOLOR 4
will display the lines and text in Red
color.
SETFLOODCOLOR
command is used to set the fill color.
SETFLOODCOLOR
1 D
FILL command is
used to fill in the desired color in a region of the graphics window containing
the turtle and the bounded lines.
SETFLOODCOLOR
[255 0 0] RT 45 FD 10 FILL
List is a
group of words separated from each other by a blank space.
Polygon is a
closed figure made up of line segments alone.
Chapter 4 - LOGO Procedures
LOGO provides two modes of operations
1.
Immediate Mode
2.
Procedure Mode
The LOGO procedure is a set of commands defined by the
user. A procedure may contain other procedures or Logo commands.
The difference between a procedure and a command is that
a command is already defined in LOGO but a procedure is a set of commands
defined by the user.
The command to enter the procedure mode is “To” followed
by the procedure name.
You end the procedure with END command.
Procedure name can be a combination of words, letters and
symbols.
No Blank space allowed between characters of procedure
name.
To execute a procedure, type procedure name and press
Enter.
To Save a procedure; File > Save
To Load a procedure; File > Load
To edit a procedure click Edall button in commander
window.
To erase a procedure use ERASE command
Primitive is a
built-in LOGO command.
Procedure is a
set of commands defined by the user.
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