Saturday, February 26, 2011

Security Problems with Multiprogramming and Time-Sharing Environments




In a multiprogramming and time-sharing environment, several users share the system simultaneously. This situation can result in various security problems. Name at least two of these problems. Can we ensure the same degree of security in a time-share machine as we have in a dedicated machine? Explain your answer ...

1. Stealing or copying of other files

     This usually happen in multiprogramming and time-sharing environment, in most cases the user’s files (the original owner of the files) was being over written by other users. This dilemma will lead to stealing or copying of files which greatly affects many users and because of that it create a negative impact in all other users(who have their original files taken by others) to engage in a multiprogramming and time-sharing environment. They believe that once your file where found by other users they will directly copy it and even without your permission that is why most of the users were very vigilant when it comes to this particular machine. And also the ability of the virus to enter in a specific files which causes the files to be damage. In multiprogramming and time-sharing environment it usually happen because of the number of users which is actually connected to each other in which the virus easily transfer and spread from user to another, and if take for granted it may cause a lot more problems. But virus is easily detected by anti-computer virus so there is a small possibility that a virus can enter on your computer.

2. Using system resources (CPU, disk space) without proper accounting

     In a multiprogramming and time-sharing environment basically when the system resources such as CPU and disk space are not properly accounted it causes the printer to mix output by sending data while some other user's file is printing. This thing may result to scrambling of mix output which cases the users to have an unfamiliar data or output and most probably the user will find it difficult in compiling his/her mixed outputs again and that will lead him/her hard time in working with it.


Can we ensure the same degree of security in a time-share machine as we have in a dedicated machine?

Definitely no, why do I say so? Firstly, because in a time-sharing machine as what I have explained earlier it is not safe to use all files that you've worked for is not permanently secured and there is a tendency that it might be copied by other users when found.
            Secondly, it is virus prone. In most cases virus-spread is vulnerable most especially when there are lots of users on that time share machine. It may cause further damage on the files and other important programs if you don’t take it seriously. While in a dedicated machine not all files but most files were secured from being copied by other users and because it is dedicated machine it is not virus prone so there is no need to worry with regards to virus.
            And lastly, when we talk about the degree of security dedicated machine is more reliable because not all users can enter on it in return they don’t have the chance to change any files so it is applicable to anyone. Even though time-sharing machine is very helpful because you work with other users or other people but when it comes to the degree of security dedicated machines is much more reliable.





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