ITGS Notes #9

Vertical Market and Custom Software

• Tends to cost far more than mass-market applications
• Job Specific Software
• medical billings
• library cataloging
• legal reference software
• restaurant management
• single client software needs

System Software:

• a class of software that includes the operating system and utility programs handles these details and hundreds of other tasks behind the scenes

"Originally Operating systems were envisioned as a way to handle one of the most complex input/output drives. But, the operating system quickly evolved into an all-encompassing bridge between your PC and the software you run on it." Ron White in How computers Work

Operating System Functions:
-supports multi-tasking
-manages virtual memory
-maintains file system
-responsible for authentication and authorization

What is the difference between authentication and authorization?
Authentication:
Authentication is a process of identifying a user based on their credentials(means user id and password).

Authorization:
Authorization is process of determining whether an authenticated user is allowed to access a specific resource or not.
What does the operating system do?

Utility Programs

• -Serve as told for doing system maintenance and repairs that aren't automatically handled by the operating system
• -Make it easier for users to
• -copy files between storage devices
• -repair damaged data files
• -translate files so that different programs can read them
• Guard against viruses and other potentially harmful programs
• compress files so they can take up less disk space
• perform other important tasks
• Symantec Norton Utilities is a popular utility package that includes software tools for recovering damaged files repairing damaged disks and improving disk performance

Device Drivers

• Small programs that enable I/O devise-keyboard, mouse, printer, and others-t communicate with the computer

Where the Operating System Lives:

• some computers store their operating system in TOM
• Others include only part of it in ROM
• The remainder of the operating system is loaded into memory in  process called booting which occurs when you turn on the computer

Most of the time the operating system works behind the scenes
interacting with the operating system like interacting with an application can be intuitive or challenging and it depends on something called the use interface
The interface defines the look and feel of the computing experience from a human point of view
Desktop Operating Systems
-MS-DOS is a disk operating system in which the user interacts user characters such as letters, numbers, and symbols
Feature include:
-command line interface                          
-menu driven interface
Graphical User Interface:
-Mac OS was developed by Macintosh in 1984
-Microsoft Windows is now the most popular operating system
Multiple User Operating: UNIX and Linux
-UNIX was developed at Bell Labs before personal computers were available
-Linus was created by Linus Torvalds and continues to be a work in progress
UNIX allows a time sharing computer to communicate with several other computers or terminals at once
-Linux is free for anyone to use or improve
-UNIX remains the dominant operating system for Internet services
Some form of UNIX is available for personal computers work stations servers main frames and super computers.
Cross-platform applications such as Microsoft Office and Adobe Photoshop are programs that are availabe in similar vrsion for multiple platforms.
Mac Users can buy software emulation programs that:
-Create a simulated Windows