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Home > BIOS Systems > BIOS Index Pages > How Operating Systems Work
 
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Overviews
These pages will provide an understanding of what the Basic Input Output System is and how it works in a personal computer.
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On This Page:
How Operating Systems Work
Overview Of System Files
Overview Of CMOS Settings
Components Of An Operating System
Internet and Network Controls
Gaming and Multimedia Control
Hard Disk Device Control
Application and Software Control
Hardware Device Control
File and Folder Management
Introduction To The Basic Input Output System The Power On Self Test (POST Routine) CMOS Settings What's On Board?
How Operating Systems Work BIOS Upgrades Page BIOS Beep Codes
 
Video Demonstration
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How Operating Systems Work

Visual Guide To Operating Systems Controls

Once the POST routine completes testing all devices control is given to the operating system. The operating system further initializes system files and hardware components so that once a graphical or text based user interface loads, the computer and its respective devices can be accessed.

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Overview Of System Files

To understand the boot up process, the first thing to discuss is the location of various start up files. 

After the POST procedure has finished, the BIOS instructs several files to be loaded. These files are listed in the chart below:

FILE LOCATION ON THE HARD DISK PURPOSE
COMMAND.COM Root directory of the hard drive.  The root directory on a hard drive is usually C:\ The basic command interpreter available in most operating systems such as DOS and Windows.  Command.com includes basic commands for copying & renaming files, making directories, and is a neccessary file in any operating system.
AUTOEXEC.BAT Root directory of the hard drive. A batch file containing various device drivers and shortcuts to applications that execute every time the system is booted up.
CONFIG.SYS Root directory of the hard drive. The file that loads various device drivers each time the system boots up.  It is a configuration file system for DOS system and executes any commands found within the system.  Common commands within the config.sys file include BUFFERS=x, FILES=x.
MSDOS.SYS (a hidden file) Hidden file.  You can’t see this file but it is typically stored in the root directory of C:\ Standard MSDOS operating system file used to control various devices within a computer system.
IO.SYS (a hidden file) Hidden file.  You can’t see this file but is typically stored in the root directory of C:\ Standard operating system file that contains various input/output configuration commands.
Table 1.1 Location and purpose of various MSDOS startup files.

Table 1.1 above lists several key files required by an operating system.  If the COMMAND.COM file is missing or corrupted your system will be halted as it contains key commands for interacting with files and data stored with the personal computer.  Additionally, Windows 95 requires that you have the CONFIG.SYS file in the root directory of your hard drive because there are certain required elements needed by Windows 95 to boot efficiently. One further element that should be understood about BIOS is the CMOS (Complimentary Metal Oxide Semiconductor) element.  The CMOS stores valuable information regarding the various elements found within a PC. 

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Overview Of CMOS Settings

The following table shows certain settings and configuration settings stored within the CMOS chip:

  Devices Controlled Through The BIOS
  Date and Time Memory
CMOS Types of floppy drives CPU type and speed
SETTINGS Types of hard drives Voltage levels
  Communication ports  
  IRQ Settings  

Any changes changes to the items listed above will be stored in the CMOS chip when the computer is turned off. You will need to consult your motherboard documentation to get a complete overview of any BIOS functions.  Changing settings in the BIOS may cause your system to behave differently, or not boot up at all, so it's imperative that you know what settings are being changed and what you should do if problems arise.

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Components Of An Operating System

In its most basic terminology, an operating system is a suite of software applications and utilities that perform basic computer tasks such as accepting input from a keyboard or mouse, sending output to a computer display, and organizing files and directories on storage mediums. The operating system during boot time can control and initialize a wide variety of other devices including the keyboard, mouse, game controllers, sound and network cards, and other input/output devices.

There are a wide variety of free and commercial operating systems but most fall into two categories: text based and graphical user interface (GOOEY) based. The most popular single user operating systems include Windows XP and OS/2. Some popular multi-user operating systems include UNIX, Linux, and Windows Server 2003.

Internet and Network Controls

The operating system facilitates the processes of connecting to the Internet and sharing resources across local area networks.

How to Access the Network Setup Wizard in Windows XP
1. Left click Start.
2. Left click Control Panel.
3. In the control panel left click the Network Setup wizard shortcut.

The network setup wizard in Windws XP makes connecting to local area network resources and the Internet a simple task.

The Network Setup Wizard provides an easy method for setting up multiple PC's through one Internet connection. It also prepares a network for file and printer sharing automatically installing the neccessary protocols and software so that all computers on the network can share files, folders, and printers.
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Gaming and Multimedia Control

Windows simplifies the entire multimedia process through DirectX a proprietary set of software and utilities that extend the multimedia experience in Windows.

How to Run Multimedia Diagnostics in Windows XP
1. Left click Start.
2. Left click Run.
3. In the open box type the command: dxdiag and press enter.
4. The DirectX Diagnostic tool willl load information about the multimedia platform currently in use by Windows.

 

The Windows XP Device Manager simplifies the process of installing, configuring, and troubleshooting hardware device drivers.

The DirectX diagnostic tool provides a simple way to troubleshoot and identify potential multimedia related problems in Windows.

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Hard Disk Drive Control

Windows controls how files and folders are organized, and how the hard disk interacts with other components of the computer.

How To Determine What's Working and What's Not
A red X shown within a device indicates the device might be disabled and re-enabling it might help during troubleshooting.
A yellow exclamation point shown within a device indicates that the device might not have the correct drivers loaded.

 

The Windows XP Device Manager simplifies the process of installing, configuring, and troubleshooting hardware device drivers.

To determine if there are problems with any hard drive or storage medium inside Windows, use the Device Manager to isolate where the problem is coming from. Once you have the device manager loaded, double click the disk drives shortcut.

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Application and Software Control

The operating system facilitates the processes of installing and uninstalling software. Windows has an Add or Remove Programs feature which permits for the easy addition and removal of software applications.

How To Access Add Or Remove Programs
1. Left click Start.
2. Left click Control Panel.
3. In the control panel left click the Add or Remove Programs shortcut.

 

 

The Windows XP Device Manager simplifies the process of installing, configuring, and troubleshooting hardware device drivers.

The Add Or Remove Programs function included in all versions of Windows lists any software installed in the computer. To easily remove software locate the title of the program, left click once, and left click the remove button. This will start the uninstall program for the particular application.

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Hardware Device Control
The operating system facilitates how devices such as mice, keyboards, and printers function. One of the main duties of the OS is to direct how device drivers should be installed or uninstalled when hardware is added to or removed from a system. It's also responsible for controlling how the hardware functions. In case problems arise a good rule of thumb is to isolate the problem through the Windows Device Manager. Problematic devices are usually emphasized as not working by an exclamation point or red X symbol.

How To Determine What's Working and What's Not
A red X shown within a device indicates the device might be disabled and re-enabling it might help during troubleshooting.
A yellow exclamation point shown within a device indicates that the device might not have the correct drivers loaded.

The Windows XP Device Manager simplifies the process of installing, configuring, and troubleshooting hardware device drivers.

The Device Manager included in all versions of Windows provides an "at-a-glance" look referencing each hardware component and associated device driver installed in a computer. The OS facilitates the processes of installing and uninstalling components using the device manager.

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File and Folder Management

Windows also provides a very easy method to manage files and folders on local and network hard drives.

How to Access Windows Explorer To Manage Files and Folders
1. Left click Start.
2. Left click run.
3. In the open box, type the command explorer and press enter or left click the OK button.
4. This will load Windows explorer, the primary file management utility loaded into all versions of Windows. From this program you can delete, rename, add, and modify existing files and folders.

 

The Windows XP Device Manager simplifies the process of installing, configuring, and troubleshooting hardware device drivers.

Windows Explorer is the primary application included with all versions of Windows that allows for easy manipulation of files and folders on local and shared network drives.

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