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computer_basics:operating_system_fundamentals [2013/02/19 23:08] mithatcomputer_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\\
-Feb192012+Dec42019
  
 ===== The Operating System ===== ===== The Operating System =====
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     * Providing a user interface for communication     * Providing a user interface for communication
  
-===== Function 1: Starting the computer =====+===== OS function 1: Starting the computer =====
   * OS's first job is to load itself into RAM   * OS's first job is to load itself into RAM
-    * Called **booting**+    * Called **booting**.
  
-===== Function 1: Starting the computer =====+===== OS function 1: Starting the computer =====
  
 {{:computer_basics:ch04-booting.jpg?direct&300|}}\\ {{:computer_basics:ch04-booting.jpg?direct&300|}}\\
 Booting: six steps Booting: six steps
  
-===== Function 1: Starting the computer =====+===== Booting step 1: BIOS and EFI =====
  
-  * //**Booting Step 1**//: Load **BIOS (Basic Input/Output System)** instructions into memory +  * Many computers use a **BIOS (Basic Input/Output System)** to begin the booting process. 
-  * BIOS allows computer to +  * The first thing that is loaded into memory and starts running when you turn on. 
-    Accept keyboard input +  * Manages some core hardware settings. 
-    * Show information on the monitor +  Handles the very first stages of the booting process. 
-  * BIOS is usually stored on a ROM chip.+  * Usually stored in flash memory or CMOS memory chip.
  
-===== Function 1: Starting the computer ===== +===== 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.+
  
-===== Function 1: Starting the computer ===== +  Most newer desktops and laptops use **EFI (Extensible Firmware Interface)** instead of a BIOS. 
-  //**Booting Step 3**//: Load the operating system +    * ** UEFI (Unified Extensible Firmware Interface)** is one example
-    * BIOS loads the **kernel** into memory+  Like a mini OS. 
-      kernel: the central part of the OS +  Does everything BIOS does. 
-    The kernel is usually stored on the hard drive+  * Lets user run small utility applications that run on the Extensible Firmware Interface
-    The OS then loads remainder of what's needed.+  Considered more secure than traditional BIOS.
  
-===== Function 1Starting the computer ===== +===== Booting step 2Test 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 the system configuration for **device drivers** +  Confirms that both the computer and its peripheral devices are working properly.
-      * device driver: utility program that enables communication between the OS and peripheral device. +
-    * The OS installs and loads the needed drivers.+
  
-===== Function 1Starting the computer ===== +===== Booting step 3Load the operating system ===== 
-  * //**Booting Step 5**//: Load system utilities +  * BIOS or EFI loads an OS'**kernel** into memory. 
-    * 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.
  
-===== Function 1Starting the computer ===== +===== Booting step 4Check the system configuration ===== 
-  * //**Booting Step 6**//: Authenticate users +  * The OS checks the system configuration for **device drivers**. 
-    * If necessary, facilitate authentication/login, user name and password+    * device driver: utility program that enables communication between the OS and peripheral device. 
 +  * The OS installs and loads the needed drivers.
  
-===== Function 2: Managing applications =====+===== 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 2: Managing applications =====
   * **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.
  
-===== Function 3: Managing memory =====+===== OS function 3: Managing memory =====
   * The OS   * The OS
     * gives each program a portion of RAM memory.     * gives each program a portion of RAM memory.
     * keeps them from interfering with each other.     * keeps them from interfering with each other.
-  * OS processes often involve using a **buffer** 
-    * An area that holds data temporarily to make programs run faster 
-    * RAM memory functions as the buffer. 
  
-===== Function 3: Managing memory ===== +===== OS function 3: Managing memory ===== 
-  * 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 of pages are temporarily stored in a swap file, a special hard disk file.+    * When RAM is full, the contents of the most inactive page or pages are temporarily moved to **swap file**, a special hard disk file
 +    * 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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 {{:computer_basics:ch04-virtualmemory.jpg?direct&600|}} {{:computer_basics:ch04-virtualmemory.jpg?direct&600|}}
  
-===== Function 3: Managing memory =====+===== OS function 3: Managing memory =====
   * Adding more RAM is often a good 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.
  
-===== Function 4: Handling input and output =====+===== OS function 4: Handling input and output =====
   * Applications access input and output devices via the OS.   * Applications access input and output devices via the OS.
   * Device drivers enable communication between the OS and input and output (and other) devices.   * Device drivers enable communication between the OS and input and output (and other) devices.
  
-===== Function 5: Providing the user interface =====+===== OS function 5: Provide a user interface =====
   * The **user interface** allows the user to:   * The **user interface** allows the user to:
     * Start application programs     * Start application programs
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 a) graphical, b) menu-driven, and c) command-line user interfaces a) graphical, b) menu-driven, and c) command-line user interfaces
  
-===== Function 5: Providing a user interface =====+===== OS function 5: Provide a user interface =====
   * Types of user interfaces:   * 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 interface**:     * **menu-driven interface**:
-      * 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.1361315315.txt.gz · Last modified: 2013/02/19 23:08 by mithat

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