Protection scheme in unix, Operating System

Assignment Help:

Q. Consider a system that holds 5000 users. Presume that you want to allow 4990 of these users to be able to access one file.

a. How would you denote this protection scheme in UNIX?

b. Could you propose another protection scheme that is able to be used more effectively for this purpose than the scheme provided by UNIX?

Answer:

a. There are two processes for achieving this:

1. Create an access control record with the names of all 4990 users.

2. Put these 4990 users in one group as well as set the group access accordingly. This scheme can't forever be implemented since user groups are restricted by the system.

b. The universal access to records applies to every user unless their name appears in the access-control list with different access permission. With this scheme you merely put the names of the remaining ten users in the access control list but with no access privileges allowed.


Related Discussions:- Protection scheme in unix

Operating system abstractions, When we download a movie from the Internet, ...

When we download a movie from the Internet, we don't care about, say, packet sizes. However, even ifwe are not aware of howlow-level details of networks are implemented, our data i

Explain briefly the working of semaphore with example ?, Explain briefly th...

Explain briefly the working of semaphore with example ? The E.W. Dijkstra (1965) abstracted the key idea of mutual exclusion in his concepts of semaphores. Definition A s

Explain concept of buffering, Buffering Messages exchanged by communica...

Buffering Messages exchanged by communication processes reside in a impermanent queue. Such a queue can be executed in three ways. Zero capacity: The queue length is 0.

Explain interrupts, Interrupts The hardware mechanism that enables a de...

Interrupts The hardware mechanism that enables a device to inform the CPU is called an interrupt. The basic interrupt mechanism works as follows. The CPU hardware has a wire kn

Explain doscreatethread functions used in the os/2, Explain DosCreateThread...

Explain DosCreateThread Functions Used in the OS/2  DosCreateThread(&threadID,MyThreadFunction,arg,flags,stackSize) DosCreateThread creates a thread within the context of th

Utility programs, Utility Programs: those programs which are not the essen...

Utility Programs: those programs which are not the essential part of operating system. But they provide different utilities / features to the users e.g. MS-DOS : Fdisk, FORMAT, AT

Define the features to implement top down parsing, Define the features are ...

Define the features are needed to implement top down parsing                      Source string marker, Prediction making mechanism and Matching and Backtracking mechanism

What are conditions under which a deadlock situation arise, What are condit...

What are conditions under which a deadlock situation may arise? A deadlock situation can arise if the following four conditions hold simultaneously in a system: a. Mutual ex

Define the throughput of a system, Define the “Throughput” of a system  ...

Define the “Throughput” of a system  Throughput is Number of programs processed by it per unit time

Determine the reasons for poor response time, Determine the reasons for Poo...

Determine the reasons for Poor response time Process busy or High I/O rates or High paging rates

Write Your Message!

Captcha
Free Assignment Quote

Assured A++ Grade

Get guaranteed satisfaction & time on delivery in every assignment order you paid with us! We ensure premium quality solution document along with free turntin report!

All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd