OS Flashcards
What is a process in an operating system?
A process is a program in execution. It is a container that holds all the information needed to run a program, including its address space, resources, and other relevant data.
What is the purpose of the process table in an operating system?
operating system table that stores information about each process currently in existence. It contains the necessary details, such as the process’s address space, registers, open files, related processes…
How does a multiprogramming system handle multiple active processes?
operating system periodically switches between running processes. This is done to ensure fair CPU utilization and prevent a single process from consuming excessive CPU time. The system saves the state of a process when it is suspended and later restarts it from the same state.
What is interprocess communication?
It allows processes to exchange data and coordinate their actions to accomplish a common goal.
What is virtual memory in an operating system?
It allows the operating system to store parts of a process’s address space on disk while keeping a portion in main memory.
What is a file system in an operating system?
It allows users and programs to create, remove, read, and write files. The file system hides the complexities of disk and I/O devices, presenting a uniform interface for interacting with files.
How are files organized in a directory hierarchy?
directory hierarchy or tree structure. Directories can contain files and other directories, forming a hierarchical arrangement. Path names are used to specify the location of a file within the directory hierarchy, with the root directory as the starting point.
What is the purpose of mounting a file system?
Mounting a file system allows it to be attached and integrated into the existing directory hierarchy. enables access to files on different storage devices, such as hard disks, CD-ROMs, or USB drives
What are special files in UNIX?
They are used to represent I/O devices as files.
block special files: model devices with randomly addressable blocks (disk)
character special files: represent devices that handle character streams (printer)
How do pipes facilitate communication between processes?
are pseudofiles that provide a communication channel between two processes. Process A can write data to a pipe, simulating an output file, while process B can read from the same pipe, treating it like an input file.
Input/Output (I/O)
Operating systems manage input and output devices such as keyboards, monitors, and printers. There is device-independent I/O software as well as device-specific software called device drivers.
Protection (OS)
Access to files is controlled through permissions, which are assigned using protection codes. Security issues, including protection against intruders and viruses, are addressed by the operating system.
The Shell
is a command interpreter, although it is not part of the operating system itself. It serves as the interface between the user and the operating system. The shell interprets user commands, executes programs, and manages input and output redirection
