Ch10 data transfer
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Ch10 data transfer Presentation Transcript

  • 1. 1 Chapter # 10 Data Transfer Prepared by :Sir Abdul Wajid
  • 2. 2 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.
  • 3. 3 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.
  • 4. 4 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.
  • 5. 5 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
  • 6. 6 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
  • 7. 7 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.
  • 8. 8 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.
  • 9. 9 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.
  • 10. 10 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.
  • 11. 11 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).
  • 12. 12 Examples  Thermometer  Analog Clocks  Position of compass dial  Room light dimmer switch  Speed of the car  Petrol Stations
  • 13. 13 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
  • 14. 14 Examples  Digital clocks  Calculators  Score board  Bar codes  Traffic light sequence
  • 15. 15 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
  • 16. 16 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.
  • 17. 17 Demodulator  Wires convert the analogue signal back into a digital one that the computer is able to understand.
  • 18. 18 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.