Chapter 4 Continued

Web Applications

• Web applications fall into several categories
• Some simple Web applications perform simple data-processing tasks that could also be performed by traditional programs running on stand-alone PCs. Ex: Blogs
• Most Web applications take advantage of the Web’s connectivity.
• Many Web applications leverage the Web’s strength as a huge repository of information.
• Some Web applications support online business transactions.
• News-oriented Web applications provide up-to-the-minute reports on a myriad of subjects.
• Other Web applications support a more traditional form of information broadcasting.
• Web applications take advantage of web connectivity

Integrated Applications and Suites: Software Bundles
Vertical -Market and Custom Software
• Very expensive compared to mass market applications
mass-market applications
• Job-specific software: Medical billings, Library cataloging, Legal reference software, Restaurant management, Single-client software needs

The Hardware-Software Connection
• 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.
System Software:
The Hardware-Software Connection
• Operating system functions:
• Supports multitasking
• Manages virtual memory
• Maintains file system
• Responsible for authentication and authorization

Utility Programs and Device Driver
• Utility programs: Serve as tools 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 (as described in the chapter on computer security and risks)
• Compress files so they take up less disk space
• Perform other important, if unexciting, 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 devices—keyboard, mouse, printer, and others—to communicate with the computer.

• Included with the operating system or bundled with peripherals

Where the Operating System Lives
• Some computers store their operating system in ROM.
• Others include only part of it in ROM.
• The remainder of the operating system is loaded into memory in a 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 user interface.


The User Interface
The Human–Machine Connection

• User Interface: The interface defines the look and feel of the computing experience from a human point of view.
• Desktop Operating Systems
• MS-DOS ( Microsoft Disk Opening System)is a disk operating system in which the user interacts using characters:
• Letters
• Numbers
• Symbols

• Features include:

• Command-line interface (commands are typed)

• Menu-driven interface (commands are chosen from on-screen lists)

• Graphical User Interfaces (GUI)

• Mac OS was developed by Macintosh in 1984 using GUI.

• Microsoft Windows is now the most popular operating system.
Multiple User Operating Systems: UNIX and Linux
• UNIX was developed at Bell Labs before personal computers were available.
• Linux was created by Linus Torvalds and continues to be a work-in-progress.
• UNIX allows a timesharing 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 servers.
• Some form of UNIX is available for personal computers, workstations, servers, mainframes, and supercomputers.
Hardware and Software Platforms
• Windows Vista
• Windows Server 2003
• Windows XP
• Windows ME
• Microsoft Windows CE
• Mac OS X (10)
• Mac OS 9
• Linux, Sun Solaris, and other UNIX variations

• Cross-platform applications, such as Microsoft Office and Adobe Photoshop, are programs that are available in similar versions for multiple platforms.

• Mac users can buy software emulation programs that:

• Create a simulated Windows machine in the Mac .

• Translate all Windows-related instructions Mac equivalents.



• Future applications may be more tied to networks than to desktop computer platforms.

• Microsoft .NET strategy

• Java, a platform-neutral computer language developed by Sun Microsystems for use on multiplatform networks.