Unix

Question 1

List Key Advantages of Linux over other Unix variants.

Answer 1

• Ability to dynamically load and unload kernel code on demand
• Preemptive
• No differentiation between threads and processes.
• Object-oriented device model with device classes, hot pluggable events, and user-space device file system (sysfs)
• Free, open development model
• Multi-user, multi-tasking, and portable

Question 2

A program that provides the user a command-line interface (CLI) to the kernel.

Answer 2

Shell

Question 3

A running program; an instance of a program in execution.

Answer 3

Process

Question 4

A program that runs unobtrusively in the background, rather than under the direct control of a user, that waits for activation by the occurence of a specific event or condition.

Answer 4

Daemon

Question 5

Similar to threads in Windows, this shares most, if not all, of its logical address space and system resources with other processes.

Answer 5

Lightweight Process

Question 6

The fundamental interface between an application and the Linux kernel.

Answer 6

System Call Interface

Question 7

A wrapper function for a system call of a Linux kernel. These are part of the standard C library and are either static (.a) or dynamically linked shared object (.so)

Answer 7

Library Function

Question 8

What are the two rings of Unix?

Answer 8

User Mode (Unprivileged) and Kernel Mode (Privileged)

Question 9

What are the User Mode components?

Answer 9

• Applications
• Windows Manager
• Libraries

Question 10

What are the components of the Kernel Mode?

Answer 10

• System Call Interface
• Process Management
• Inter-process Communication
• Virtual File System
• Memory Management
• Network Subsystem
• SELinux
• Drivers and Dynamic Modules
• Architecture Dependent Code (Board Support Packages)

Question 11

What is the Hardware Component?

Answer 11

Processor Architecture

Question 12

A family of related standards specified by the IEEE that defines the API of a UNIX OS.

Answer 12

Portable Operating System Interface for uniX (POSIX)

Question 13

What are some user initiated processes?

Answer 13

• Shells
• UNIX Commands
• Utility Programs
• User Application Programs
• Libraries (GNU C Library glibc)

Question 14

Provides the user interface to the kernel; Linux CLI is an example.

Answer 14

Shell

Question 15

What is an implementation of the standard C library used by many OSs and programs on those systems?

Answer 15

GNU C LIbrary (glibc)

Question 16

What manages system resources and performs system services and is loaded into memory at system boot and is the core of the OS?

Answer 16

Kernel mode

Question 17

What is a catastrophic crash that halts the entire PC called?`

Answer 17

Kernel panic

Question 18

What does the kernel use to communicate user requests to kernel services which then converts a process running in user mode to a protected kernel mode process?

Answer 18

System Call Interface (SCI)