<p>What are the characteristics of a multitasking operating system?<br>
What makes it multitasking?<br>
Are there non-multitasking operating systems?</p>

[{'answer_id': 79268, 'author': 'Brian R. Bondy', 'author_id': 3153, 'author_profile': 'https://Stackoverflow.com/users/3153', 'pm_score': 2, 'selected': False, 'text': "<p>A multi tasking operating systems is:</p>\n\n<p>An operating system that gives you the perception of 2 or more tasks/jobs/processes running at the same time.  It does this by dividing system resources amongst these tasks/jobs/processes.  And switching between the tasks/jobs/processes while they are executing very fast over and over again.</p>\n\n<p>Yes there are non multi tasking operating systems, example: commodore 64's OS (Commodore BASIC 2.0).  Probably some custom made software for some companies.  Perhaps like an ATM machine, or movie theater stub ticket system.</p>\n"}, {'answer_id': 79271, 'author': 'André Chalella', 'author_id': 4850, 'author_profile': 'https://Stackoverflow.com/users/4850', 'pm_score': 1, 'selected': False, 'text': '<p>A multitasking OS is able to manage various processes side-by-side. One particular ability is the sharing of CPU time among the processes.</p>\n\n<p>Yes, there are plenty of non-multitasking OSs. Back in time, they were the rule: MSDOS, for example.</p>\n'}, {'answer_id': 79283, 'author': 'Chris Upchurch', 'author_id': 2600, 'author_profile': 'https://Stackoverflow.com/users/2600', 'pm_score': 5, 'selected': True, 'text': '<blockquote>\n  <p>What are the characteristics of a multitasking operating system? What makes it multitasking?</p>\n</blockquote>\n\n<p>Multitasking operating systems allow more than one program to run at a time.  They can support either preemptive multitasking, where the OS doles out time to applications (virtually all modern OSes) or cooperative multitasking, where the OS waits for the program to give back control (Windows 3.x, Mac OS 9 and earlier).</p>\n\n<blockquote>\n  <p>Are there non-multitasking operating systems?</p>\n</blockquote>\n\n<p>Any OS that only allows one thing to be done at a time (DOS for instance).</p>\n'}, {'answer_id': 79290, 'author': 'Thomas', 'author_id': 14637, 'author_profile': 'https://Stackoverflow.com/users/14637', 'pm_score': 0, 'selected': False, 'text': '<p>I\'m not sure if you\'re supposed to ask your homework questions here... ;)</p>\n\n<p>A multitasking OS allows you to run multiple processes (tasks) "simultaneously". They do not actually run at the same time, of course, since there is only one CPU. What happens is that one process runs for a while, then the OS breaks in (through an interrupt), stores away the state (context) of the current process, restores the context of another, and allows that other process to run for a while, etcetera.</p>\n\n<p>MS-DOS is an example of a non-multitasking OS: as long as you\'re playing Commander Keen, no other tasks can run on your computer (including the DOS shell itself).</p>\n'}, {'answer_id': 79299, 'author': 'Ben Collins', 'author_id': 3279, 'author_profile': 'https://Stackoverflow.com/users/3279', 'pm_score': 1, 'selected': False, 'text': '<p>From the dinosaur OS book ("Applied operating System Concepts"):</p>\n\n<p><strong>Time sharing,</strong> or <strong>multitasking</strong>, is a logical extension of multiprogramming.  The CPU executes multiple jobs by switching among them, but the switches occur so frequently that the users can interact with each program while it is running.</p>\n'}, {'answer_id': 79315, 'author': 'Vinko Vrsalovic', 'author_id': 5190, 'author_profile': 'https://Stackoverflow.com/users/5190', 'pm_score': 0, 'selected': False, 'text': '<p>A (preemptive) multitasking OS is able to run more than one process simultaneously and has control over which process is using the CPU and other resources at each time, as opposed to a cooperative multitasking OS where the processes had to voluntarily relinquish the CPU, leading to hangs and crashes. </p>\n\n<p>Usually, modern multitasking OSs also provide memory isolation between processes and support  different security levels, allowing OS code to do things user code cannot.</p>\n'}, {'answer_id': 79337, 'author': 'Jörg W Mittag', 'author_id': 2988, 'author_profile': 'https://Stackoverflow.com/users/2988', 'pm_score': 0, 'selected': False, 'text': "<p>There's a popular non-multitasking OS that's not been listed yet: PalmOS.</p>\n"}, {'answer_id': 79357, 'author': 'Chris Pietschmann', 'author_id': 7831, 'author_profile': 'https://Stackoverflow.com/users/7831', 'pm_score': 0, 'selected': False, 'text': '<p>A Multi-Tasking Operating System would be an OS that allows for the simultaneous execution of multiple (more than 1) processes. Operating Systems that you are used to, like Unix, Windows and OSX are multi-tasking operating systems.</p>\n\n<p>An example of a non-multi-tasking operating system would be MS-DOS. Although you could get multiple processes to run simultaneously under MS-DOS, with the help of Windows 3.1 or Windows 9x, the OS itself was non-multi-tasking.</p>\n\n<p>For more information regarding Computer Multi-Tasking you may want to check out the wikipedia page: <a href="http://en.wikipedia.org/wiki/Computer_multitasking" rel="nofollow noreferrer">http://en.wikipedia.org/wiki/Computer_multitasking</a></p>\n'}, {'answer_id': 79363, 'author': 'Benoit', 'author_id': 10703, 'author_profile': 'https://Stackoverflow.com/users/10703', 'pm_score': 0, 'selected': False, 'text': '<p><a href="http://en.wikipedia.org/wiki/Computer_multitasking" rel="nofollow noreferrer">Wikipedia</a> has a pretty good lowdown on multitasking.</p>\n'}, {'answer_id': 3474020, 'author': 'kunjam aggarwal', 'author_id': 417480, 'author_profile': 'https://Stackoverflow.com/users/417480', 'pm_score': 0, 'selected': False, 'text': '<p>A multi-tasking o/s is an o/s that allows a user to simultaneously run various tasks at the same time. Actually it is not so because there is only one cpu. The concept behind this is time sharing. The operating system divides cpu time among various tasks, but this time is very small (nanoseconds) that the user feels that all programs or tasks are running simultaneously.</p>\n'}, {'answer_id': 3501511, 'author': 'vivek', 'author_id': 422738, 'author_profile': 'https://Stackoverflow.com/users/422738', 'pm_score': 0, 'selected': False, 'text': "<p>It's just an illusion for the user that parallel working is done, but not exactly like this.</p>\n"}, {'answer_id': 3610651, 'author': 'ashley', 'author_id': 436098, 'author_profile': 'https://Stackoverflow.com/users/436098', 'pm_score': 1, 'selected': False, 'text': '<p><strong>Timesharing/multiasking</strong> is a logical extension of multiprogramming.A multi-tasking os allows multiple jobs to be executed simultaneously by switching amoung them.Usually CPU process only one task at a time but the switcthing is so fast that it looks like CPU is executing multiple processes at a time.</p>\n'}]
['https://Stackoverflow.com/questions/79248', 'https://Stackoverflow.com', 'https://Stackoverflow.com/users/10703/']