An operating system concept that refers to the combination of a program being executed and bookkeeping information used by the operating system. Whenever you execute a program, the operating system creates a new task for it. The task is like an envelope for the program: it identifies the program with a task number and attaches other bookkeeping information to it.
OLTP (online transaction processing) is a class of program that facilitates and manages transaction-oriented applications, typically for data entry and retrieval transactions in a number of industries, including banking, airlines, mailorder, supermarkets, and manufacturers. Probably the most widely installed OLTP product is IBM's CICS (Customer Information Control System).
The ability to execute more than one task at the same time, a task being a program. The terms multitasking and multiprocessing are often used interchangeably, although multiprocessing implies that more than one CPU is involved.
The ability of an operating system to execute different parts of a program, called threads, simultaneously. The programmer must carefully design the program in such a way that all the threads can run at the same time without interfering with each other.
Joined: 23 Nov 2006 Posts: 19270 Location: Inside the Matrix
Tasks run directly under control of the operating system. Transactions typically run under the control of a task (i.e. CICS is a task). If you perform a "diaplay active" you will see all of the currently running batch tasks as well as all of the CICS tasks.
Multitasking is what you see with the "display active". An example of multithreading is DB2 (or any other multi-user database system) - many batch and online process are serviced concurrently by the same database system.
Think of a transaction as a trip to the store, you decide you need something, get your keys and wallet, get in the car, drive to the store, find the needed item, purchase it, drive back home and go inside. Think of a task as one of the many small pieces of the preceding transaction, i.e., getting your keys and wallet, getting in the car, driving to the store, finding the needed item, purchasing it or driving back home.
multitasking and multithreading..
Think of multitasking as what is being done when tune the radio while you are driving the car, switching attention from one task to the other. Think of multithreading as what is being done when you tune the radio while your friend is driving the car, each person paying attention to their own task.