Unit 1 - Operating Systems (OS)

Batch

In a computer, a batch job is a program that is a program that is assigned to the computer to run without further user interaction. Some are defined to run automatically at a certain time.

cache

In computer science, this is a component that acts like your web history. It stores data transparently so that future requests for that data can be served faster.

kernel

In computing, this is a computer program that manages input/output requests from software and translates them into data processing instructions. It is a fundamental part of the modern computer's operating system.

SHELL

In computing, this is a user interface for access to an operating system's services. OS shells use either CLI or GUI, depending on a computer's role and particular operation.

Root

In the computer world, this refers to the top-level directory of a file system. The word is derived from a tree root, since it represents the starting point of a hierarchical tree structure.

What default authentication for Windows and what key encryption does it use?

Kerberos and it uses symmetric key cryptography.

Boot Process

Once the PC is turned on, the BIOS (basic input/output system) initializes the hardware, then calls code stored in the MBR (512-bytes) at the start of disk 0. The MBR loads code from the boot sector of the active partition, the the boot sector loads and runs the bootloader from the file system. Once the bootloader is finally executed, it loads its configurations/database from files on the same partition. The bootloader optionally presents the user with a list of operating systems as loaded from the configuration file, known as the Boot Menu. Then, the bootloader locates and loads the kernel for the selected OS from the disk, and hands-off control of the PC to the OS.

Graphical User Interface (GUI)

Pronounced "gooey", this is a user interface that includes graphical elements, such as windows, icons, and buttons.

Master Boot Record (MBR)

This is a small section of a hard disk or other storage device that contains information about the disk.

What are Operating Systems (OS)?

This is a software which acts as an interface between the end user and computer hardware. Every computer must have at least one OS to run other programs.

Command Line Interface (CLI)

This is a text-based interface that is used to operate software and OS while allowing the user to respond to visual prompts by typing single commands into the interface and receiving a reply in the same way.

Electrically Erasable Programmable Read-Only Memory (EEPROM)

This is a user-modifiable read-only memory (ROM) that can be erased and reprogrammed repeatedly through the application of higher that normal electrical voltage. Does not need to be removed from the computer to be modified.

Disk Operating System (DOS)

This is an operating system that runs from a hard disk drive. The term can also refer to a particular family of disk operating systems, most commonly MS-DOS (Microsoft Disk Operating System).

daemon

This serves the function of responding to network requests, hardware activity, or other programs by performing some tasks. It can also configure hardware, run scheduled tasks, and perform a variety of other tasks.

cd \

Windows CLI Command that moves to the root folder of the file system.

type filename

Windows CLI Command that types a file.

Types of OS

Windows, Linux/Unix, Apple, Android, etc...

cd pathname

Windows/Linux CLI Command that changes directory (folder) in the file system.

cls/clear

Windows/Linux CLI Command that clears the CLI window.

exit

Windows/Linux CLI Command that closes the CLI window.

copy/cp

Windows/Linux CLI Command that copies a file to another folder.

mkdir or md/mkdir

Windows/Linux CLI Command that creates a new directory (folder).

Dir/Is

Windows/Linux CLI Command that lists the directory (folder) system.

move/mv

Windows/Linux CLI Command that moves a file to another folder.

cd ..

Windows/Linux CLI Command that moves one level up (one folder) in the file system.

rmdir or rd/rmdir

Windows/Linux CLI Command that removes a directory (folder).

help/man command

Windows/Linux CLI Command that shows the manual for a given command.