Characteristics
Different methods of Multi-tasking
Multi tasking is when the operating system seems to be performing two or more tasks at the same time, i.e. MS Word and MS Access, however these tasks are not actually running simultaneously as they are actually resident in memory processor is actually switching between tasks at a very high speed, therefore each user sees their own task as having priority. One disadvantage can be that the more programs that are run by the user, the more memory that is required. Multi Tasking can be split into two categories, co-operative and pre-emptive.
Co-operative is when the process currently controlling the CPU must offer a balanced share of the CPU to all other processes, hence Co-operative, as all processes must co-operate for it to work properly. Subsequently an MUOS will allow two or more users a share of the system resources at the same time. The use of the resources must be spread evenly between the requirements of the users so that a problem with one user does not become a problem between all users. Examples of co-operative multi tasking would be Windows 3x and Macintosh.
Pre-emptive is when the applications are forced to share the CPU whether they want to or not and examples of this are Windows 95, NT and UNIX.
How print sharing operates?
NOS - A print server allows multiple users access to a single printer. A print server will also give you information on the use of the printer. All print jobs are sent to a Network Printer, controlled by the server, where they will wait in turn to be printed. For example, you can:
Ø See how many people are using the printer;
Ø Set limits to the usage;
Ø Give higher priority to some workstations, allowing them to print before others;
Ø See who is currently printing or;
Ø See when your print job is coming up.
MUOS - The Multi-User Operating System Linux uses a printing system called LPD, which constantly runs as a
Bibliography: http://www.cert.org/tech_tips/usc20_full.html#A13 Dick, David (2002) The P.C