1. MEASURING DATA
BITS AND BYTES

2. Understanding Data
 Data (the plural of datum) are anything
in a form suitable for use with a
computer. Whatever a computer receives
as an input is data. Data are raw facts
without any clear meaning. Computers
process data and generate information.
 All data stored and processed by
computers are in the form of whole
numbers. The purpose of the numbers
becomes clear after they are interpreted
and displayed by software.

3. Part of the data stored in the computer for the file apple.bmp
The apple.bmp File

4. Decimal Number System

5. Binary Number System

6. Bits and Bytes
 We measure computer information
(data) in bits and bytes. Bit is short for
binary digit. It is the smallest unit of
information that a computer can
understand. One bit represents a 1 or
0 digit in a binary numeral or a true or
false logical condition. A bit is
represented physically by high or low
voltage in a circuit or a small
magnetized spot on a disk.

7. Bits and Bytes
Byte is short for binary term. A byte
usually contains eight bits. It can represent
a single character, such as a letter, a
digit, or a punctuation mark.
Because a byte represents only a small
amount of information, we usually
measure amounts of computer memory
and storage in
 kilobytes (one kilobyte is 1024 bytes),
 megabytes (one megabyte is 1048576
bytes),
 gigabytes (one gigabyte is 1073741824

8. Bits and Bytes
In Bytes In Bits In Bits
(Power Notation)
3
1 byte 2 bits 8 bits
10
1 kilobyte (KB) 2 bytes 1024 bytes
20
2 bytes 1024 kilobytes
1 megabyte (MB)
30
2 bytes 1024 megabytes
1 gigabyte (GB)
40
2 bytes 1024 gigabytes
1 terabyte (TB)
50
2 bytes 1024 terabytes
1 petabyte (PB)
60
2 bytes 1024 petabytes
1 exabyte (EB)
70
2 bytes 1024 exabytes
1 zettabyte (ZB)
80
2 bytes 1024 zettabytes
1 yottabyte (YB)

9. Binary, Decimal and
Hexadecimal Numbers

11.  512 MB = ……………...…....… GB
 64 b = …………........……… B
 5120 GB = ………....……...…… TB
 4096 PB = …….....………...…… EB
 0.25 GB = .......………………… MB

12. TAKING CARE OF THE
COMPUTER

13. Monitor Cleaning

14. Keyboard Cleaning

15. Mouse Cleaning

16. Case Cleaning

17. Keep Your PC Cool
 Buy Quality Hardware
 Get Power Protection
 Get an Anti-Virus Program
 Scan for Other Malware
 Run the Defragmenter Utility
 Clean Up Old Files

18. HEALTHY COMPUTER USE
Make Yourself Comfortable
 Put the computer on a flat table at a comfortable height and
distance to avoid hurting your eyes; make sure that the display is
a bit below your eye level.
 Put the computer directly in front of you when you work. Make
sure you have enough space to operate the different parts of the
computer (keyboard, mouse, etc.) easily.
 If you use a paper holder, put it at about the same height and
distance from you
as the monitor.
 Set your chair height so that
the keyboard is at (or slightly
below) the level of your
elbow. You should be able to
type comfortably with your
shoulders relaxed.

19. HEALTHY COMPUTER USE
Make Yourself Comfortable
 Your knees should be slightly higher than your hips. If
necessary, use a foot rest to raise your knees.
 Set the back of your chair so that it supports the lower
part of your spine.
 Sit straight so that your knees, hips, and elbows are
at about 90 degree angles when you work. Do not
lean forward or back too far.
 If possible, use soft,
indirect lighting in your
computer work area.

20. HEALTHY COMPUTER USE
Take a Break
 Change your position
often. If you use a
computer for a long time,
stand up and stretch your
wrists, hands, and legs
regularly.
 Take frequent short
breaks (for example, two
or three minutes every
half hour) instead of one
or two long breaks.

21. HEALTHY COMPUTER USE
Eyes and Eyesight
 Working at a screen for a long time without a break
can have effects similar to reading or writing
uninterruptedly and may make your eyes feel tired or
sore.
 Every fifteen or twenty minutes, look at an object that
is far away to avoid hurting your eyes with too much
close work.
 Put the computer so that sunlight or bright indoor light
does not reflect off the screen and hurt your eyes.
 Have regular eye examinations.
Visit a doctor if your body hurts
or aches because of too much
computer work.

22. BUYING A COMPUTER
 Your Needs
 Windows vs. Mac
 Desktop vs. Laptop
 Hardware
 Software
 Service, Support and Warranty