With reference to a diagram explain the actions of a Unixbas

With reference to a diagram, explain the actions of a Unix-based operating system when a process invokes the fork system-call. Three common file allocation mechanisms, in order of increasing complexity, are contiguous, chaining, and indexed. Briefly describe one advantage and one disadvantage of each mechanism.

Solution

Answer:-

Advantages and disadvantages of unix operating system :

Advantages :-

1) Unix provides true multi-user multitasking protected memory operation while using a minimal amount of memory.

2) Unix also provides solid user security provides account validation and authentication. In Unix everything is a file including the terminal and all devices which simplifies input/output operations.

3) Linux is very portable which means it can run on a number of different hardware platforms making it easy for users to install on whatever hardware they choose to use.

Disadvantages :

1) Unix is not a very user-friendly operating system. Its basic interface is the command line and even experienced users can make mistakes using this interface and mistakes in Unix can be disastrous.

2) Those commands as well as their options can be cryptic and even though there are numerous utilities and applications for the Unix/Linux platforms which is an advantage of sorts it can be too much for someone new to Unix. In addition documentation on many of these tools is hard to find and is also often incomplete.

Advantages and disadvantages of Fork system call :

Advantages :

1) Fork it\'s creates a child process which is almost identical to the parent process . The fork must copy all the parent process\'s memory.

2) The fork() syscall generates two identical processes with separate memory.

Disadvantages :

1) The fork() is treatment of the parent and child address space. By definition fork() duplicates the parents address space.
2) If fork is followed by exec that address space is discarded.
3) The fork() consumes a lot of system resources (CPU, memory, I/O, etc.). it decreases the reliability stability and predictability of your system.
4) if not used with care, it can lead to system overloads, process table stacking , memory leaks, deadlocks, disk database inconsistency. it is recommended that if you can do all things using one process, then don\'t fork() off any child.