Path: utzoo!utgpu!news-server.csri.toronto.edu!rpi!zaphod.mps.ohio-state.edu!cis.ohio-state.edu!ucbvax!bloom-beacon!bloom-picayune.mit.edu!athena.mit.edu!pshuang From: pshuang@athena.mit.edu (Ping-Shun Huang) Newsgroups: comp.windows.ms Subject: Re: Is MS-Windows.....? Message-ID: Date: 11 Jun 91 19:22:22 GMT References: Sender: news@athena.mit.edu (News system) Distribution: usa Organization: Massachusetts Institute of Technology Lines: 21 In-Reply-To: jones@hal.uvm.edu's message of 10 Jun 91 21:36:37 GMT In article jones@hal.uvm.edu (Mike Jones) writes: > 1.) Non-preemptive multi-tasking. (i.e. does a routine have to yield the > CPU on it's own) > 2.) pre-emptive (kernel gives each process a slice of CPU time.) Both. Windows 3.0 running in 386 enhanced mode can use time-slicing to provide CPU time to DOS applications running in virtual-86 boxes, but it depends on non-preemptive, cooperative multitasking *BETWEEN* real Windows applications. In other words, if you have a Windows app which is being a CPU hog by not yielding properly, the other Windows application starve for cycles, but DOS apps will still get their time slices. Example: you have Wordperfect 5.1 and Word for Windows and another buggy Windows app multitasking together. The buggy app goes into a loop where it does not make the proper system call to yield the CPU. Word for Windows will grind to a halt, but Wordperfect will not. -- Singing off, UNIX:/etc/ping instantiated (Ping Huang).