Introduction to the Unix Operating System

These flashcards cover key concepts related to the Unix operating system, system calls, and dual-mode operations.

System call

A mechanism for programs to request services from the operating system's kernel, facilitating controlled access to system resources.

Dual-Mode Operation

User Mode (limited) and Kernel Mode (privileged instructions).

Kernel

It serves as the core part of the operating system, managing interactions between hardware and software.

0: read, 1: write, 2: read/write.

List the three file operation modes in Unix.

Process control, file manipulation, device manipulation, information maintenance, communications.

categories of system calls

The system interface to the kernel.

lowest level of interaction with Unix

Acts as a limitation for user applications to prevent them from executing privileged operations.

What is the role of the user mode in Dual-Mode Operation?

They can be supported without resorting to assembly language.

How are system calls typically implemented in high-level languages?

It provides a facility through which applications interact with the kernel.

What is the significance of the system interface to the kernel?

Disk drives and network interfaces.

Can you name two types of devices that are manipulated by system calls?

'read' system call

It reads data from a file descriptor into a buffer.

'write' system call

It writes data from a buffer to a file descriptor.

demand paging

It loads pages into memory only when they are needed, rather than loading all at once.

It determines the order in which processes receive CPU time.

What is the function of CPU scheduling in an operating system?

Notifications sent to a process in order to notify it of specific events.

What does the term 'signals' refer to in a Unix operating system?

Creating, reading, writing, and altering file attributes.

What is a file manipulation system call responsible for?

Requesting and releasing devices for use.

What is a 'device manipulation' system call used for?

It manages how data is stored and retrieved.

What is the 'file system' in the context of Unix?

Time and date information.

What do information maintenance system calls commonly retrieve?

Assembly language is usually used, but higher-level languages like C can also be used.

What language is primarily used for implementing system calls?

It manages process operations like loading, executing, ending, and aborting processes.

Describe a 'process control' system call.