CompuServe Messages

Dom, I'm not a techy but my understanding of Windows multitasking is that each application has to be programmed to release the processor for other programs. If the program isn't written correctly it will hog the system. Also, while one program is running, the other effectively halts until the first one is finished. I believe this is the way the Mac also works. Also, each program has to be writen to allow m/ting instead of the OS taking care of that. This partly results in longer development cycles and large applications. The Amiga, OS/2, WindowsNT & Unix (me thinks) all use premptive m/t. What happens here is that each program is given a priority as to where it is postioned on a task list. The processor runs through the task list with each clock cycle and any program that is waiting for processing is done for a certain amount of time. Once it's time limit is up the processor goes to the next application and so on. Although theoretically only one program is being run at a time the effect is that all programs are more or less equally sharing the processor, as required. The difference between AmigaDOS & both NT & OS/2 is that the PC operating systems support multithreaded m/t. What happens here is that an application can start a new thread, or procedure, within itself. So, for example, a word processor can do a seach and replace while you continue to edit the file. Therefore, each program is internally multitasking. I hope this is more fact than fiction. I'm sure someone else will correct me if I'm wrong. 8^) Andrew