computer_basics:operating_system_fundamentals
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computer_basics:operating_system_fundamentals [2012/09/26 04:02] – mithat | computer_basics:operating_system_fundamentals [2019/12/06 03:53] – 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 part 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 2: Managing applications | + | ===== Booting step 5: Load system utilities |
- | * **Multitasking** operating systems permit more than one application to run at the same time. | + | * Antivirus software |
- | * The foreground application is the active one. | + | * Speaker volume control |
- | * The backgrounds applications appear inactive. | + | * Etc. |
- | ===== OS Function 3: Managing memory | + | ===== 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. | ||
- | * The OS gives each program a portion of RAM memory and keeps them from interfering with each other. | + | ===== OS function 2: Managing applications ===== |
- | * Often involves using a **buffer** | + | * **Multitasking** operating systems permit more than one application to run at the same time. |
- | * An area that holds data and instructions temporarily and makes programs run faster | + | * The **foreground application** is the active one. |
- | * RAM memory functions as the buffer | + | * The **background applications** appear inactive. |
- | ===== OS Function | + | ===== OS function 3: Managing memory ===== |
- | * RAM is organized into **pages**: units of large fixed size containing program instructions and data. | + | * The OS |
- | * Virtual memory uses a portion of the hard disk to extend RAM. | + | * gives each program a portion of RAM memory. |
- | * When RAM is full, copies | + | * keeps them from interfering with each other. |
- | * Transferring files between RAM and the hard disk is called paging. | + | |
+ | ===== OS function | ||
+ | * RAM is organized into **pages**: units of large fixed size. | ||
+ | | ||
+ | * When RAM is full, the contents | ||
+ | * When the page is again needed, it is transferred back into RAM. | ||
+ | | ||
===== Virtual memory ===== | ===== Virtual memory ===== | ||
{{: | {{: | ||
- | ===== 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 computer | + | * Applications access input and output devices via the OS. |
- | * Interrupts, signals created by input and output devices, notify the OS when actions are taken. | + | * Device drivers enable communication between the OS and input and output |
- | ===== 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 | ||
* Safely shut down the computer | * Safely shut down the computer | ||
+ | * Perform other interactions | ||
===== User interfaces ===== | ===== User interfaces ===== | ||
{{: | {{: | ||
- | (a) graphical, | + | a) graphical, b) menu-driven, |
- | + | ||
- | ===== OS Function 5: Providing the user interface ===== | + | |
- | * A **graphical user interface (GUI)** uses **icons** and other visual metaphors. | + | |
- | ===== OS Function | + | ===== OS function |
- | * A **menu-driven** | + | * Types of user interfaces: |
- | * Provides text-based menus | + | * **graphical user interface (GUI)** uses **icons** and other visual metaphors. |
- | * Displays available user options | + | * **menu-driven |
- | * A **command-line** | + | * Provides text-based menus. |
- | * Requires the user to type commands to instruct the OS to perform the desired actions | + | * Displays available user options. |
+ | * **command-line | ||
+ | * 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