Lecture 2
- 2. A data is defined as a collection of facts . Thus, sales reports, inventory figures, test scores, customers’ names and address and weather reports are all example of data. Data processing is the manipulation of data into a more useful form. It is the modern name for paperwork and involves the collecting, processing, and distributing of facts and figure s to achieve a desired result.
- 3. DATA PROCESSING CYCLE Input- In this step the initial data or input data are prepared in some convenient form for processing. The form will depend on the processing machine. Processing – In this step the unit data are changed, and usually combined with other information, to produce data in a more useful form.
- 4. Output – This is the results of the preceeding processing , steps are collected. The particular form of the output data depends on the use of data.
- 6. Expanded Data Processing ∗ 1. Origination – Origination is a step which refers to the processing of collecting the original data. The original recording of data is called a source document. ∗ 2. Distribution- This refers to the distribution of the output data. Recordings of the data are often called report data. ∗ 3. Storage – Storage is crucial in many data processing procedure. Data processing results are frequently placed in storage to be used as input data for future processing at a later date.
- 8. Areas of Data Processing 1. Business Data Processing – Business Data Processing is characterized by the need to established, retain, and process files of data for producing useful information. Generally, it involves a large volume of input data, limited arithmetical operations, and a relatively large volume of output. 2. Scientific Data Processing – In science, data processing involves a limited volume of input and many logical or arithmetic calculations. Unlike business problems, most of the scientific problems are non repetitive, requiring “onetime” solution.
- 9. Data Processing Operations 1. Recording – Recording refers to the transfer of data onto some form or documents . It relates to the documentation of intermediate figures and facts resulting from calculations. 2. Verifying – Since recording is usually a manual operation, it is important that recorded data be carefully checked for any errors. 3. Duplicating- This operation consist in reproducing the data onto many forms of documents.
- 10. 4. Classifying - This operation separates data into various categories. Identifying and arranging items with like characteristics into groups or classes called classifying. 5. Sorting – Arranging data in a specific order is called sorting. After the data classified, it is usually necessary to arrange or rearrange them in predetermined sequence to facilitate processing. 6. Calculating – Arithmetic manipulation of the data is known as calculating. It is a crucial phase of data manipulation, because the outcome of this operation becomes part of the output.
- 11. 7. Summarizing and Reporting – In this operation, a collection of data is condensed and certain conclusions from the data are represented in a meaningful format. 8. Merging- This operation takes two or more sets of data, all sets having been sorted by the same key, and puts them together to form a single sorted set of data. 9. Storing – Placing similar into files for future reference is storing.
- 12. 10. Retrieving – Recovering stored data and/or information when needed is the retrieving step. 11. Feedback – Feedback is the comparison of the output(s) and the set in advance; any discrepancy is analyzed, corrected and fed back to the proper stage in the processing operation.
- 13. Methods of Processing Data 1. Batch Processing – Batch processing is a technique in which data to be processed or programs to be executed are collected into group to permit convenient, efficient and serial processing. 2. On-line Processing – The term “on-line” refers to equipment or devices under the direct control of the central processing unit (CPU) of a computer. 3. Real-Time Processing - Real time processing is a method of data processing which has the capability of fast response to obtain data from an activity or
- 14. physical process , performs computations, and return a response rapidly enough to affect the outcome of the activity or process. 4. Distributed Processing - The most complex level of computer processing is distributed processing, generally consists of remote terminals linked to a large central computer system to help the user conduct inquiries about accounts, process jobs, or data processing operation.
- 15. CPU Components ∗ 1. Control Unit –the control unit of the CPU supervises or monitors the functions performed by the entire computer system according to conditions set forth by the stored programs. ∗ 2. Arithmetic/Logic Unit – It performs the operations such as addition, subtraction, multiplication and division, as well as moving, shifting and comparing data. Logic operations are performed on a computer by a series of comparisons activated by this unit.
- 16. ∗ 3. Memory Unit – Memory unit is somewhat like an electronic filling cabinet capable of holding data or instructions. It is where the computer program and data are stored during processing.
- 17. ∗ Basic Components of Digital Computer System Memory unit Input unit Arithmetic and Logic unit Register Control Unit Central Processing Unit Output Unit