Published on November 17, 2010
Data Processing : Data Processing Slide 2: A processing mode is the way in which transactions are grouped and handled for input to the central processor for computation or generation of reports and outputs. Batch processing system : Batch processing system A technique in which a number of similar items or transactions to be processed are grouped (batched) for processing as a single unit at predetermined times. Slide 4: A batch of transactions is accumulated, batch total complied for it, the transactions transcribed on floppy diskette or other media at regular intervals for a predetermined period of time (say weekly, monthly, daily, etc.) after which it is processed to produce the desired output. Slide 5: Payroll. Stores ledgers etc. Online processing : Online processing In an On-line-direct-access system, the input data enters the system from the point of origin and output is transmitted directly back to the user. This system implies direct communication between the CPU and the user for both input and output. Two essential requirements for Online-processing system: : Two essential requirements for Online-processing system: Terminals located in various departments/ locations of an organization, connected to, and controlled by the main computer. Slide 8: Storage of records in such a way that the computer directly accesses a particular record by its identifying records key, without having to search through a sequence of records which is possible only if records are stored on a direct-access storage device like floppy disk/ hard disk. Slide 9: Apart from transaction processing and file updating, inquires are also handled by the Online-Processing System. Example: : Example: A salesman wanting to know the availability of a stock as desired by his customer whose accounts are more than 3 months past due.. Further, online processing ensures that the records are in updated status at any time where as with batch processing it is say one week or so. But on-line processing is usually more costly. Online system applications: : Online system applications: Banking system: Online systems are being used to inform bank customers of the status of their account in response to an inquiry by accessing the relevant file using an online terminal. Slide 12: Airline reservation system: which receive requests from the terminals of hundreds of travel agents about booking seats on a particular flight on a particular date. Slide 13: Stock exchanges: Terminals located in major stock exchanges throughout the country and the offices of participating brokerage firms enable the speedy processing of share dealings. Benefits provided by Online Systems : Benefits provided by Online Systems Information is centralized: Dissemination of information: Reduction in paper works: Improved accuracy: As terminal messages are checked for accuracy before being transmitted to the computer by data validation programs, the quality of information in a system increases as the input errors are reduced and the information is more reliable. Slide 15: Elimination of tedious tasks: Routine clerical tasks are replaced by terminal operations providing a greater degree of job interest, operating efficiency and job satisfaction. Real-time Systems : Real-time Systems Real time refers to the technique of updating files with transaction data immediately after the event to which it relates occurs. Real-time systems are on-line systems with tighter constraints on response time. In these systems the data is processed and results are generated fast enough to influence ongoing activity. Slide 17: Characteristics of real time systems include: Only a small volume of data is processed at any one time. Turnaround is critical. Processing efficiency is subordinate to response need. The system responds to and often controls its environments and the processing keep pace with external events. Slide 18: 5. Fairly fast response time (is only a fraction of a second), allowing two-way communication, i.e. interaction between the user and the central processor. 6. Decision to be made on the basis of the latest information available from files which are getting continuously updated. Applications of Real-time Systems : Applications of Real-time Systems Enquires about customer’s account status can be answered in seconds. Credit appraisal can be carried out immediately. Time-Sharing : Time-Sharing Time-sharing is a term used to describe a processing system with a number of independent, relatively low-speed, on-line, simultaneously, usable stations which are geographically remote from the computer and from each other. Slide 21: Each station provides direct access to the central processor for obtaining instant responses to the questions asked or statements made in an interactive conversational mode. Slide 22: The speed of the system and the use of multiprogramming allow the central processor to switch from one using station to another and to do a part of each job in the allocated ‘time slice’ until the work is completed. Multiprogramming Systems : Multiprogramming Systems A technique for handling two or more independent programs simultaneously by overlapping or interleaving their execution or by loading them into primary storage and executing their instructions concurrently. Multiprocessing : Multiprocessing Pertaining to the simultaneous execution of two or more computer programs or sequences of instructions by a computer system. Frequently refers to simultaneous execution accomplished by the use of a system with more than one central processor. Slide 25: A hardware and software architecture which allows more than one processor to work on different parts of a program at the same time. Applications of multiprocessing: : Applications of multiprocessing: Where some jobs are too large for one computer to process. Where it is required to solve a considerable number of problems simultaneously and very speedily. Where a high degree of protection against breakdown is required. Distributed Data processing system : Distributed Data processing system Unlike centralized transaction processing in which all components run on the same computer, distributed transaction processing is a system in which one or more components run on separate computers and communicate across a network. Slide 28: It is a network of computer systems that fully support the data processing needs of one organization, interacting with each other and a vast database through a larger computer that oversees the entire network. The essential requisites for a system to be described as distributed are : : The essential requisites for a system to be described as distributed are : Computer processing ability is situated at more than one location. This facility is applied to user-oriented tasks. A data transmission facility to enable the interconnection of the locations. Some element of data handling at each location. Certain common standard of the conduct of operations must be followed.