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15. What do you mean by cpu scheduler?
Ans. CPU scheduling is the task performed by the CPU that decides the way and order in which processes should be executed. There are two types of CPU scheduling - Preemptive, and non-preemptive. CPU Scheduling is a process of determining which process will own CPU for execution while another process is on hold. The main task of CPU scheduling is to make sure that whenever the CPU remains idle, the OS at least select one of the processes available in the ready queue for execution. The selection process will be carried out by the CPU scheduler. It selects one of the processes in memory that are ready for execution.
16. List any two advantages & disadvantages of fcfs.
Ans. Advantages:
It is simple and easy to understand. User-Friendly Easy to Implement First Come First Served
Disadvantages :
Long Waiting Time Here, the first process will get the CPU first, other processes can get the CPU only after the current process has finished its execution. Now, suppose the first process has a large burst time, and other processes have less burst time, then the processes will have to wait more unnecessarily, this will result in more average waiting time, i.e., Convey effect. Favors CPU Bound process then I/O bound process.
17. List out any 4 functions of memory management?
Ans. Memory management is a method in the operating system to manage operations between main memory and disk during process execution. The main aim of memory management is to achieve efficient utilization of memory.
Allocate and de-allocate memory before and after process execution.
To keep track of used memory space by processes. To minimize fragmentation issues. To proper utilization of main memory. To maintain data integrity while executing of process.
18. What do you mean by Internal and External
fragmentation.
Ans. There are two types of fragmentation in OS which are given as Internal fragmentation and External fragmentation.
Internal fragmentation :
Internal fragmentation happens when the method or process is smaller than the memory. The solution of internal fragmentation is the best-fit block. Internal fragmentation occurs when memory is divided into fixed-sized partitions. The difference between memory allocated and required space or memory is called Internal fragmentation. It occurs in worst fit memory allocation method.
19. Define file with its attributes.
Ans. A file can be defined as a data structure which stores the sequence of records. Files are stored in a file system, which may exist on a disk or in the main memory.
Attributes of the File
Name : Every file carries a name by which the file is recognized in the file system. One directory cannot have two files with the same name.
Identifier : Along with the name, Each File has its own extension which identifies the type of the file. For example, a text file has the extension .txt, A video file can have the extension .mp4.
Type : In a File System, the Files are classified in different types such as video files, audio files, text files, executable files, etc.
Location : In the File System, there are several locations on which, the files can be stored. Each file carries its location as its attribute.
Size : The Size of the File is one of its most important attribute. By size of the file, we mean the number of bytes acquired by the file in the memory.
Protection : The Admin of the computer may want the different protections for the different files. Therefore each file carries its own set of permissions to the different group of Users.
Time and Date : Every file carries a time stamp which contains the time and date on which the file is last modified.
20. Define file and directory.
Ans. File is nothing but a collection of information. The information can be of numbers, characters, graphs, images, etc. Every file should be stored under a unique name for its future reference. Every file should be saved along with an extension.
