The Operating System ICS3M

 The operating system (OS) provides a consistent environment for other software programs to execute commands.  It gives the user an interface with the computer so they can send commands (input) and receive feedback (output)

The OS  To do this the OS must communicate with the hardware to perform specific tasks:  Disk and file management  Device access  Memory management  Output format  Once the OS has organized these resources users can effectively use the machine

The OS  The OS is the center through which the system hardware, other software, and the user communicate.  The OS coordinates the communication between all components of the system.

Disk and File Management  A hard disk is made up of a series of magnetic platters.  Each of these platters is divided into sectors and tracks when the hard drive is formatted.

File Management  When the drive is initially formatted a file allocation table is stored in track 0 (the outermost track)  When an operating system is installed on the drive, it appends its FAT in track 0 as well

Organizing the Disk  We can use several tricks to organize files on a disk for faster access.  Defragmenting a hard drive is one way to improve access time.

Installing an OS  Most operating systems require you to prepare a disk before you install the OS.  With Windows 9X, that means a format with either a Windows 9x or DOS boot disk.  The format erases all information currently on the drive and prepares the FAT for the new operating system.

After Installation  Installing a Windows OS usually takes between ½ to 1½ hours  After you install the OS, you must install device drivers for hardware attached to the machine  Device drivers the OS how to communicate with the hardware device  Finally you must install software to make the system useful for the user.

Installing Software  Basically, following the directions will get you through software installation easily.  The problem with software installation is licensing and copyrights.  Companies such as Microsoft are beginning to clamp down on illegal copies of their software.  Its estimated that 1 in 10 installs of MS software is illegal.

Your Task  Complete the ‘ICS3M4MOperating Systems Question Sheet’ posted on the course website