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computer_basics:operating_system_fundamentals [2012/09/26 04:26] 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\\
-Sept252012+Dec42019
  
 ===== The Operating System ===== ===== The Operating System =====
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   * Five basic OS functions:   * Five basic OS functions:
-    Starting the computer +    Starting the computer 
-    Managing applications +    Managing applications 
-    Managing memory +    Managing memory 
-    Handling input and output device messages +    Handling input and output device messages 
-    Providing a user interface for communication+    Providing a user interface for communication
  
-===== OS Function 1: Starting the computer ===== +===== OS function 1: Starting the computer ===== 
-  * The OS's first job is to 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 ===== 
 {{:computer_basics:ch04-booting.jpg?direct&300|}}\\ {{:computer_basics:ch04-booting.jpg?direct&300|}}\\
-Six steps in starting the computer+Booting: six steps 
 + 
 +===== Booting step 1: BIOS and EFI ===== 
 + 
 +  * Many computers use a **BIOS (Basic Input/Output System)** to begin the booting process. 
 +  * The first thing that is loaded into memory and starts running when you turn on. 
 +  * Manages some core hardware settings. 
 +  * Handles the very first stages of the booting process. 
 +  * Usually stored in flash memory or CMOS memory chip.
  
-===== OS Function 1: Starting the computer =====+===== Booting step 1: BIOS and EFI =====
  
-  * //**Booting Step 1**//: Load **BIOS (Basic Input/Output System)** instructions into memory +  * Most newer desktops and laptops use **EFI (Extensible Firmware Interface)** instead of a BIOS. 
-  * Allows computer to +    * ** UEFI (Unified Extensible Firmware Interface)** is one example. 
-    Accept keyboard input +  * Like a mini OS. 
-    Show information on the monitor+  Does everything BIOS does. 
 +  Lets user run small utility applications that run on the Extensible Firmware Interface. 
 +  * Considered more secure than traditional BIOS.
  
-===== OS Function 1Starting the computer ===== +===== Booting step 2Test the hardware ===== 
-  * //**Booting Step 2**//: Conduct the **power-on self-test (POST)** +  * Many BIOS/EFIs initiate a **power-on self-test (POST)** or similar test. 
-    * Confirms that both the computer and its peripheral devices are working properly.+  * Confirms that both the computer and its peripheral devices are working properly.
  
-===== OS Function 1Starting the computer ===== +===== Booting step 3Load the operating system ===== 
-  * //**Booting Step 3**//: Load the operating system +  * BIOS or EFI loads an OS'**kernel** into memory. 
-    * BIOS loads into memory the **kernel**, the central part of the OS +    * kernelthe central part of the OS. 
-    * The OS then loads remainder of what's needed+    * Usually stored on main storage device. 
 +  * The OS then loads remainder of what's needed.
  
-===== OS Function 1Starting the computer ===== +===== Booting step 4Check the system configuration ===== 
-  * //**Booting Step 4**//: Check the system configuration +  * The OS checks the system configuration for **device drivers**
-    * The OS checks the system configuration for **device drivers**---utility programs that enable communication between the OS and peripheral devices +    * device driver: utility program that enables communication between the OS and peripheral device. 
-    * The OS installs and loads the needed drivers+  * The OS installs and loads the needed drivers.
  
-===== OS Function 1Starting the computer ===== +===== Booting step 5Load system utilities ===== 
-  * //**Booting Step 5**//: Load system utilities +  * Antivirus software 
-    * Antivirus software +  * Speaker volume control 
-    * Speaker volume control +  * Etc.
-    * Etc.+
  
-===== OS Function 1Starting the computer ===== +===== Booting step 6Authenticate user ===== 
-  * //**Booting Step 6**//: Authenticate users +    * Final part of booting is to facilitate user authentication or login
-    * If necessary, facilitate authentication/logina user name and password+     * Typically a user name and password or fingerprint scan or special code.
  
-===== OS Function 2: Managing applications =====+===== 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.
  
-===== OS Function 3: Managing memory ===== +===== OS function 3: Managing memory ===== 
-  * The OS gives each program a portion of RAM memory and keeps them from interfering with each other. +  * The OS 
-  * OS processes often involve using a **buffer** +    * gives each program a portion of RAM memory
-    * An area that holds data temporarily to make programs run faster +    * keeps them from interfering with each other.
-    * RAM memory functions as the buffer+
  
-===== OS 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|}}
  
-===== OS Function 3: Managing memory ===== +===== OS function 3: Managing memory ===== 
-  * 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 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.
  
-===== OS 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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 ===== User interfaces ===== ===== User interfaces =====
 {{:computer_basics:ch04-userinterfaces.jpg?direct&600|}}\\ {{:computer_basics:ch04-userinterfaces.jpg?direct&600|}}\\
-(a) graphical, (b) menu-driven, and (c) command-line user interfaces+a) graphical, b) menu-driven, and c) command-line user interfaces
  
-===== OS Function 5: Providing a user interface ===== +===== OS function 5: Provide a user interface ===== 
-  * 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** 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.1348633593.txt.gz · Last modified: 2012/09/26 04:26 by mithat

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