1.2 Characteristics of Computer
Computers have distinguishing characters which make them ideal
machines. But they do not certain have characters which human possess. Some of
the important characteristics of computers are:
i] Automatics:
► Computers are automatic machines which
once started a job; carry it on until it is completed provided they are given
the required instructions by the users.
ii] Speed:
► The computers are capable of taking
logical decisions, performing arithmetic and non-arithmetic operations on
alphabets and copying at an unbelievable speed.
► The units of speed for a computer are in
milliseconds (10-3) or even in nano and Pico second (10-9
or 10-12)
► A powerful computer can perform 3 to 4
million arithmetic operations per second.
► The speed of the computers is attributed
to the fact that The Computers Are Electronic Devices Working On Electrical Pulses Which
Travel at High Speed.
iii] Accuracy:
► The computer produces highly accurate
and reliable results
► The errors in the calculations may be
due to the error in the logic of the human but not due to the computer.
► The computers perform accurate
calculations 'n' number of times.
iv] Versatility:
► A computer
is capable of performing a wide variety of functions.
► It can
accept data and produce results.
► It can
perform the basic arithmetic and logic operations.
► It can
transfer data internally
► Severally applications can be run at a
time. For example MS Powerpoint, Adobe Pagemaker and Windows Media Player can
be run at a time.
v] Diligence:
► A computer is capable of performing the
same task over and over again with the same degree of accuracy and reliability
as the first one.
► This is because, unlike human beings,
computers are free from monotony, tiredness, lack of concentration etc. and can
work hours together without creating bugs.
vi] Large and Perfect Memory:
► A computer can store and recall any
amount of information because of its secondary storage capability with perfect
accuracy unlike human beings.
► The storage
capacity of the computer is enormous and is perfect.
► A computer recalls a data with greater
accuracy even after several times and does not lose any information unless it
is prompted to do so.
vii] No I.Q and feelings:
► A computer
is not intelligent on its own and cannot think its own.
► It can only
perform the tasks specified by the human.
► It cannot
decide on its own and only the user can determine what the computer must do.
► A computer
has no feelings but a human does.
Table 1.3:
Measures of capacity
Kilo-(K)
|
1 Thousand
|
= 103 and 210 bytes
|
Mega-(M)
|
1 Million
|
= 106 and 220 bytes
|
Giga-(G)
|
1 Billion
|
= 109 and 230 bytes
|
Tera-(T)
|
1 Trillion
|
=1012 and 240 bytes
|
Peta-(P)
|
1 Quadrillion
|
=1015 and 250 bytes
|
Bit/Binary
Digit:
(Represent single
bit either 1 or 0 or ON or OFF). A binary digit is logical 0 and 1 representing
a passive or an active state of a component in an electronic circuit.
Nibble: 4 bits or ½ byte = 1 Nibble =
Group of 4 bit
Byte = 1 character. A group of 8 bits
is called byte. A byte is the smallest unit, which can represent a data item or
a character.
Word (2 bytes or 16 bits): = 1 Word. A
computer word, like a byte, is a group of fixed number of bits processed as a
unit, which varies from computer to computer but is fixed for each computer.
The length of a computer word is called word-size or word length. It may be as
small as 8 bits or may be as long as 96 bits. A computer stores the information
in the form of computer words.
2 Words or 32 bits
= Double word
1024 Bytes
|
1 Killobyte (KB)
|
210 or 103
|
1024 KBs
|
1 Megabyte (MB)
|
220 or 106
|
1024 MBs
|
1 Gigabyte (GB)
|
230 or 109
|
1024 GBs
|
1 Terabyte (TB)
|
240 or 1012
|
1024 TBs
|
1 Petabyte (PB)
|
250 or 1015
|
1024 PBs
|
1 Exabyte (EB)
|
260 or 1018
|
1024 EBs
|
1 Zettabyte (ZB)
|
270 or 1021
|
How many bytes equal to 1TB?
Here, from the
above table we have observed that:
1 TB = 1024 GB
= 1024×1024MB
=1024×1024×1024KB
=1024×1024×1024×1024
Bytes
= 1099511627776
Bytes
Table 1.4 Measure of Time and Speed
Unit of Time
|
Meaning
|
Part of Second
|
In the power of 10
|
Millisecond (m)
|
Thousandth of a second
|
1/1000
|
10-3 sec.
|
Microsecond (m)
|
Millionsth of a second
|
1/1000000
|
10-6 sec.
|
Nanosecond (n)
|
Billionsth of a second
|
1/000000000
|
10-9 sec.
|
Picoseconds (p)
|
Trillionth of a second
|
1/000000000000
|
10-12 sec.
|
Femtosecond (f)
|
Quadrillionth of a second
|
1/1000000000000000
|
10-15 sec.
|