computer_basics:operating_system_fundamentals
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computer_basics:operating_system_fundamentals [2012/09/26 04:11] – mithat | computer_basics:operating_system_fundamentals [2019/12/06 05:11] (current) – [Booting part 1: BIOS and EFI] mithat | ||
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Mithat Konar\\ | Mithat Konar\\ | ||
- | Sept. 25, 2012 | + | Dec. 4, 2019 |
===== The Operating System ===== | ===== The Operating System ===== | ||
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* Five basic OS functions: | * Five basic OS functions: | ||
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- | ===== OS Function | + | ===== OS function |
- | * Loads itself into RAM | + | * OS's first job is to load itself into RAM |
- | * Called **booting** | + | * Called **booting**. |
- | * Booting involves //six steps// | + | |
+ | ===== OS function 1: Starting the computer ===== | ||
- | ===== Booting process ===== | ||
{{: | {{: | ||
- | Six steps in starting the computer | + | Booting: six steps |
- | ===== OS Function | + | ===== Booting step 1: BIOS and EFI ===== |
- | * **Booting** //step 1//: Load **BIOS (Basic Input/ | + | * Many computers use a **BIOS (Basic Input/ |
- | * Allows computer to | + | * The first thing that is loaded |
- | * Accept keyboard input | + | * Manages some core hardware settings. |
- | * Show information on the monitor | + | * Handles the very first stages of the booting process. |
+ | * Usually stored in flash memory or CMOS memory chip. | ||
- | ===== OS Function | + | ===== Booting step 1: BIOS and EFI ===== |
- | * **Booting** //step 2//: Conduct the **power-on self-test (POST)** | + | |
- | * Confirms that both the computer and its peripheral devices are working properly. | + | |
- | * If any part of the POST fails: | + | |
- | * A beep will sound | + | |
- | * An error message will appear on the monitor | + | |
- | * The computer will stop | + | |
- | ===== OS Function 1: Starting the computer ===== | + | |
- | | + | * ** UEFI (Unified Extensible Firmware Interface)** is one example. |
- | * BIOS looks for the operating system | + | * Like a mini OS. |
- | * BIOS loads into memory the **kernel**, the central part of the operating system | + | * Does everything BIOS does. |
- | * The operating system loads remaining system configuration information | + | * Lets user run small utility applications that run on the Extensible Firmware Interface. |
+ | * Considered more secure than traditional BIOS. | ||
- | ===== OS Function 1: Starting | + | ===== Booting step 2: Test the hardware |
- | * **Booting** //step 4//: Check the system configuration | + | * Many BIOS/EFIs initiate a **power-on self-test (POST)** or similar test. |
- | * The OS checks | + | * Confirms that both the computer and its peripheral devices |
- | * The OS installs and loads needed drivers | + | |
- | ===== OS Function 1: Starting | + | ===== Booting step 3: Load the operating system |
- | * **Booting** //step 5//: Load system utilities | + | * BIOS or EFI loads an OS' |
- | * Antivirus software | + | * kernel: the central part of the OS. |
- | * Speaker volume control | + | * Usually stored on main storage device. |
- | * Etc. | + | * The OS then loads remainder of what's needed. |
- | ===== OS Function 1: Starting | + | ===== Booting step 4: Check the system configuration |
- | * **Booting** //step 6//: Authenticate users. | + | * The OS checks the system configuration for **device drivers**. |
- | * If necessary, facilitate authentication/ | + | * device driver: utility program that enables communication between the OS and a peripheral device. |
+ | * The OS installs | ||
- | ===== OS Function | + | ===== Booting step 5: Load system utilities ===== |
+ | * Antivirus software | ||
+ | * Speaker volume control | ||
+ | * Etc. | ||
+ | |||
+ | ===== Booting step 6: Authenticate user ===== | ||
+ | * Final part of booting is to facilitate user authentication or login. | ||
+ | * Typically a user name and password or fingerprint scan or special code. | ||
+ | |||
+ | ===== OS function | ||
* **Multitasking** operating systems permit more than one application to run at the same time. | * **Multitasking** operating systems permit more than one application to run at the same time. | ||
* The **foreground application** is the active one. | * The **foreground application** is the active one. | ||
* The **background applications** appear inactive. | * The **background applications** appear inactive. | ||
- | ===== OS Function | + | ===== OS function |
- | + | * The OS | |
- | * The OS gives each program a portion of RAM memory | + | * gives each program a portion of RAM memory. |
- | * Often involves using a **buffer** | + | * keeps them from interfering with each other. |
- | * An area that holds data temporarily to make programs run faster | + | |
- | * RAM memory functions as the buffer | + | |
- | ===== OS Function | + | ===== OS function |
- | * RAM is organized into **pages**: units of large fixed size containing program instructions and data. | + | * RAM is organized into **pages**: units of large fixed size. |
* **Virtual memory** uses a portion of the hard disk to extend RAM. | * **Virtual memory** uses a portion of the hard disk to extend RAM. | ||
- | * When RAM is full, copies | + | * When RAM is full, the contents |
+ | * When the page is again needed, it is transferred back into RAM. | ||
* Transferring files between RAM and the hard disk is called **paging**. | * Transferring files between RAM and the hard disk is called **paging**. | ||
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{{: | {{: | ||
- | ===== OS Function | + | ===== OS function |
- | * Adding more RAM is often the best way to improve computer performance because: | + | * Adding more RAM is often a good way to improve computer performance because: |
* Paging slows the computer. | * Paging slows the computer. | ||
* Accessing data from the hard disk is slower than accessing it from RAM. | * Accessing data from the hard disk is slower than accessing it from RAM. | ||
- | ===== OS Function | + | ===== OS function |
- | * **Device drivers** enable communication between the OS and peripheral | + | * Applications access input and output devices via the OS. |
+ | | ||
- | ===== OS Function | + | ===== OS function |
- | * The user interface allows the user to: | + | * The **user interface** allows the user to: |
* Start application programs | * Start application programs | ||
* Manage storage devices | * Manage storage devices | ||
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===== User interfaces ===== | ===== User interfaces ===== | ||
{{: | {{: | ||
- | (a) graphical, | + | a) graphical, b) menu-driven, |
- | ===== OS Function | + | ===== OS function |
- | * Types: | + | * Types of user interfaces: |
* **graphical user interface (GUI)** uses **icons** and other visual metaphors. | * **graphical user interface (GUI)** uses **icons** and other visual metaphors. | ||
- | * **menu-driven** | + | * **menu-driven |
- | * Provides text-based menus | + | * Provides text-based menus. |
- | * Displays available user options | + | * Displays available user options. |
- | * **command-line interface: | + | * **command-line interface**: |
- | * Requires the user to type commands to instruct the OS to perform the desired actions | + | * Requires the user to type commands to instruct the OS to perform the desired actions. |
computer_basics/operating_system_fundamentals.txt · Last modified: 2019/12/06 05:11 by mithat