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Chapter # 10
Data Transfer
Prepared by :Sir Abdul Wajid

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Data transfer
 Users often need to transfer data
between software packages or
computers.
 Until relatively recently this was difficult
to achieve, but the increasing use of
computers and the growth of ICT has
forced software designers to make this
much easier.
 File conversion from older to newer
versions of the software.

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File Conversion
 File conversion is an important part of computing
 If you r using new software version then there is a need that this
software will read the files from the old database.
 It means that old data can be converted for use on newer
systems.
 This saves considerable time because it avoids users having to re-
enter existing data onto a new system.
 It is always important to make sure that any new software were buy can
read your old files.
 Problems might arise with file conversion if the data is very old or
is formatted for a system that not longer exists.
 However, most newer version of software are usually capable of
reading data from older versions (e.g. Word97 files can be read
by Word2002)
 Most database, spreadsheet and word processing files can be read by
other packages as well .
 However it is always important to check that this compatibility
between software packages and data works.

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ASCII
 ASCII is the acronym for American Standard
Code for Information Interchange.
 ASCII is a world-wide standard code for
representing characters (letters, numbers etc.)
as binary code.
 Before its introduction, it was almost
impossible to transfer data between software
packages or computers.
 For example the letter A has the ASCII code
0100 0001 and B is 0100 0010.

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An example of ASCII
 HELLO! Is represented by the following
ASCII code:
 H 0100 1000
 E0100 0101
 L0100 1100
 L0100 1100
 O 0100 1111
 ! 0010 0001

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ASCII Files
 AMERCIAN STANDARD CODE FOR
INFORMATION INTERCHANGE.
 This code is representing characters ( letters,
numbers) as binary codes.
 All computers can store data as ASCII code and a
file used to hold ASCII code is called ASCII file.
 The 8 bit binary codes used to hold the letters of
alphabet.
 Let suppose ASCII code of character A is
A 01000001

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Transferring files between
word processors
 The most common type of the file transfer is
between different word processors.
 In large organizations people use different
versions of word processors, so there is a
need such a word processor which can be
compatible.
 The only way to transfer text between
different word processors is to store
everything as ASCII file.

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Comma separated Variables
 One common file format is “Comma
Separated Variables ” as CSV
 The CSV File format is useful because it is
possible to transfer files.
 Files in this format can be read by most
spreadsheets and databases.

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File Handling Packages
 Backing storage devices such as disk drives are able to store
files outside the CPU.
 These files could be program files which holds the series of
instruction then it will perform a useful tasks.
 We need to perform file processes such as deleting, copying or
merging files.
 If we want to say, delete or copy a large number of files then
there is a need a special software called the file packages.
 Example:
 A file used to hold a drawing you have drawn using a drawing
paint.

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Data/File Compression
 Special software is able to reduce the size of
files to about one quarter of their size.
 Zip Files are often use for that purpose
 You can also unzip or decompress the files.
 Program and data files are often compressed
before they are sent over the internet.

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Analog computers
 It provides continuous value
 It represents physical quantities in the form of
waves
 It has no state
 It has low memory
 It is difficult to use
 It is used in engineering and science
 However, although analogue computers are
quite rare they do perform certain functions
better than digital computers (e.g. controlling
manufacturing processes in a factory; certain
type of modelling).

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Examples
 Thermometer
 Analog Clocks
 Position of compass dial
 Room light dimmer switch
 Speed of the car
 Petrol Stations

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Digital computers
 It provides us discrete values
 It represent physical values with help of
symbols or numbers
 It has two states ON and OFF
 It has big memory
 These are easy to use
 It is used in all field of life

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Examples
 Digital clocks
 Calculators
 Score board
 Bar codes
 Traffic light sequence

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Analog to Digital conversion
and vice versa
 In chemical factories ,the processes used to
make chemicals are usually controlled with
the help of computers. The signals from a
temperature sensor is a continually changing
analog to Digital (ADC) .
 The computer then control the process by
outputting the digital-analog converter(DAC)
 A modem is another example

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Modulator
 In modem it is used to convert the binary
digits from a digital computer into an analog
signal that may be passed along telephone
wires.

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Demodulator
 Wires convert the analogue signal back into a
digital one that the computer is able to
understand.

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Sound Sampling
 The sound cards listens to the sound and
takes a measurement of the height of the
signal many times a second. The
measurement called sound sampling.
 The sampling rate is the number of times the
sample is measured per second called it is
kilohertz (KHz).
 The higher the sampling rate the better the
sound reproduction.