The software is a series of instructions or a special program that performs a particular task and is recorded in some form on a computer disk. Simply, the software is an abstract collection of instructions for computers to perform specific tasks. It is called differently a program or software program. Computer software has two major categories. It is typically classified into system software and application software.

Three Kinds of Programs

Systems software consists of three kinds of programs. The system management programs, system support programs, and system development programs are they. These are explained briefly.

System Management Programs

These are programs that manage the application software, computer hardware, and data resources of the computer system. These programs include operating systems, operating environment programs, database management programs, and telecommunications monitor programs. Among these, the most important system management programs are operating systems. The operating systems are needed to study more details. There are two reasons. First, users need to know their functions first. For the second, there are many kinds of operating systems available today.

Telecommunications monitor programs are additions of the operating systems of microcomputers. These programs provide the extra logic for the computer system to control a class of communications devices.

System Support Programs

These are the programs that help the operations and management of a computer system. They provide a variety of support services to let the computer hardware and other system programs run efficiently. The major system support programs are system utility programs, system performance monitor programs, and system security monitor programs (virus checking programs).

System Development Programs

These are programs that help users develop information system programs and prepare user programs for computer processing. These programs may analyze and design systems and program itself. The main system development programs are programming language translators, programming environment programs, computer-aided software engineering packages.

An operating system is a collection of integrated computer programs that provide recurring services to other programs or to the user of a computer. These services consist of disk and file management, memory management, and device management. In other words, it manages CPU operations, input/output activities, storage resources, diverse support services, and controls various devices.
Operating system is the most important program for computer system. Without an operating system, every computer program would have to contain instructions telling the hardware each step the hardware should take to do its job, such as storing a file on a disk. Because the operating system contains these instructions, any program can call on the operating system when a service is needed.

Need to Study Operating System?

There are many different computer systems and several available operating systems. Thus, users must know what each operating system can do and cannot do to meet their necessity. Today, many operating systems are used for general use or sometimes for specific use. Then, which one is best for a specific purpose? The reason that users need to study operating system is here.
The predominant microcomputer operating system for IBM and IBM-compatibles so far was DOS (Disk Operating System). It has different versions including MS-DOS, PC-DOS and others. DOS is very popular and wide spread, but it has some limitations. Users need to learn DOS although it may fade out in a few years and has some weakness, because it will be used for the next several years. The other popular operating system was the Apple Macintosh operating system.
As more powerful microcomputers become commonplace, more advanced operating systems are needed. Microcomputer users are beginning to demand more powerful operating system that can run powerful microcomputers more efficiently. Today's very powerful microcomputers are demanding more complex and refined operating system that can do multifunctions. They also ask an easier user interface than old operating systems did. Now, there are more than six popular operating systems, leading to the lack of a standard. The other reason that operating system should be learned is here.

How the Operating System Uses Memory

Here explains in case of DOS. When a personal computer is turned on, it searches specific locations on the disk drives for operating system files. If the PC finds the files, it loads the first of them into memory. A set of operating system files then takes over, loading the rest of the main files into memory in a specific order. Because the operating system is in a sense, loading itself or lifting itself by its own bootstraps, this operation is called the boot-up.
At the lowest part of memory, the operating system loads a table of interrupt vectors. When the operating system receives special codes called interrupts, it uses the table to detect where in memory it can find matching instructions. DOS also uses a small area just above the interruption table to hold the BIOS data called 'flags' that record the state of various system conditions. The same area also acts as a buffer to store keystrokes that come in faster than the system can process them.
A large expanse of memory just above the BIOS flags and keyboard buffer is used for device drivers, utility programs, and application programs. When DOS reads the CONFIG.SYS and AUTOEXEC.BAT files, it looks for command lines to load drivers or memory-resident programs. Memory- resident programs are those that continue to be active even when application programs are running. When it finds such a command line, DOS normally puts the driver or program at the start of this large memory area. Device drivers usually remain loaded until the PC is turned off. Memory- resident programs can be unloaded if no other programs are loaded after them.

Operating System Functions

An operating system executes many functions to operate computer system efficiently. Among them, four essential functions are the followings.

• Resource Management: An operating system manages a collection of computer hardware resources by using a variety of programs. It manages computer system resources, including its CPU, primary memory, virtual memory, secondary storage devices, input/output peripherals, and other devices.

• Task Management: The function of the operating system that controls the running of many tasks. It manages one program or many programs within a computer system simultaneously. That is, this function of operating system manages the completion of users' tasks. A task management program in an operating system provides each task and interrupts the CPU operations to manage tasks efficiently. Task management may involve a multitasking capability.

• File management: This is a function that manages data files. An operating system contains file management programs that provide the ability to create, delete, enter, change, ask, and access of files of data. They also produce reports on a file.

• User Interface: It is a function of an operating system that allows users to interact with a computer. A user interface program may include a combination of menus, screen design, keyboard commands. A well-designed user interface is essential for an operating system to be popular. Because of the function, users can load programs, access files, and accomplish other tasks.

Virtual Memory

This is a technique for an operating system to manage memory. An operating system simulates significantly larger memory capability than the real memory capacity of its actual primary storage unit. It allows computers to process larger programs than the physical memory circuit would allow.

Multitasking

This refers the capability of operating systems that runs several computing tasks in one computer at the same time. This is controlled by the task management program in an operating system. It's also called multiprogramming and multithreading.

DOS stands for Disk Operating System. In the early 1980s, Microsoft got the right to QDOS (Quick and Dirty Operating System) developed by a small company, Seattle Computer, and then has been sold it under the name MS-DOS. Microsoft licenses a version called PC-DOS to IBM (International Business Machines) for its IBM personal computers, and its version, MS-DOS, to many other PC manufacturers.

Advantages and Disadvantages

• Advantages: DOS has many advantages. The advantages will be the reasons for learning DOS. DOS is the most popular microcomputer operating system for IBM computers and compatibles ever sold worldwide. It runs thousands of applications, and is easy to use. DOS is easy for novices to use, and many publications and books are available for the operating system. DOS runs on low- priced IBM computers and compatibles. DOS does not require an expensive computer system while some others still do.

• Disadvantages: DOS has some drawbacks, but there is no doubt that we will continue to see DOS used in the 1990s. It will then slowly be replaced as the dominant operating system. The hardware has evolved in significant ways. New microcomputers have more capacity and faster electronics than the old IBM PC and compatibles. This makes DOS an old operating system.
  DOS has direct access to only 640 kilobytes of primary storage, although new microcomputers have much more primary storage. This restriction is an inherent limitation of DOS. Today's new software for word processing, graphics, spreadsheets, and database management requires more primary storage. In addition, DOS is a single tasking operating system. It can support only one user and one program at a time.
  Another disadvantage is that DOS has a character-based interface. A graphical user interface is easier to the users than the character-based interface.

File Access Table(FAT)

DOS creates a FAT for each disk during formatting. Every sector on the disk is represented by an entry in the FAT as part of a cluster. DOS looks for available clusters when a file is enlarged or created. When DOS allocates files on a freshly formatted disk, DOS uses the first cluster and sequences through a connected series of clusters, leaving many never-used clusters at the end of FAT. When a file is erased or shortened, DOS marks the released clusters in the FAT as available again. When a file is allocated more than one cluster, each cluster points to the next cluster that contains more of the files. The pointer is the next cluster number. The result is a chain of clusters that comprise the map of a file's disk storage. Thus, FAT acts as a storage map and tells DOS exactly where to go on the disk to get all parts of a file.

How Application Programs Run in DOS

When the user specifies the application software to work on, the RAM part of memory is filled with that image of that software. For example, if the user wants to use WordPerfect, the command is taken from the command line and the corresponding software is loaded on to the RAM and it works like a word processor.

Files on DOS Disks

The files on DOS disks have specific purposes. A COM file extension identifies a command file. Command files are the names of external DOS commands. Files with CPI extensions operate the display screen. A file with the DAT extension is a data file. Files with BAT extension are batch files. AUTOEXEC.BAT is a special batch file that runs automatically when a computer is started. EXE files are executable program files. SYS files are system files. SYS files are used to add or modify hardware support to the basic PC operation.

This is a graphics-based operating environment from Microsoft. This operating system runs under DOS. Thus, it is usually called "DOS with windows." Windows 3.x allows multiple tasking, allowing users to open several applications simultaneously and shift between them. Windows operating system is very similar to the Macintosh desktop environment.
Windows 3.x is a major upgrade of Microsoft's earlier versions. It provides a DOS extender that allows Windows 3.x applications to run in up to 16MB of memory. In the Windows, users can run DOS applications and change data between them.

Modes

Windows 3.x has three different operating modes.

• Real Mode: This mode is for computers with less than 1MB of memory. It uses expanded memory if available, and does not use extended memory.

• Standard Mode: This is a normal Windows 3.0 operating mode. It works with extended memory (XMS). This mode allows users to use DOS applications in the window environment by allowing users to switch between DOS applications and windows applications. The mode also uses expanded memory (EMS) if available.

• 386 Enhanced Mode: This mode is the extension of Windows/386 version that runs on 386 and higher CPUs. This mode allows multitasking of Windows and standard DOS applications. It converts character-based programs (DOS applications) to bit-mapped graphics (Windows applications). It activates EMM386.SYS memory manager to use EMS memory.

Advantages and Disadvantages

• Advantages: Windows allows multitasking capability and more primary memory. Windows provides a memory manager to allow users to access more than 640KB of conventional memory. Another benefit of it is that it has a dynamic data exchange function. Dynamic data exchange allows one program (e.g., a word processing program) to request data or information from other programs (e.g., a spreadsheet program or a database program etc.) currently running and use those information. A graphical user interface (GUI) against character- based approach is another advantage. This allows users to use Windows environment such as mouse, pointer, clicking, icon, or pull-down menu.

• Disadvantages: Windows 3.x can handle multitasking, but it is really switching between tasks. Windows 3.x is not a multithreaded operating system. This works well for many applications, but for some information and data can be lost if Windows does not get back to a task soon enough. There are many application programs for Windows, but users frequently demand more powerful application programs that exceed the capabilities of current Windows programs. The other disadvantage is that Windows 3.x was not originally intended for networks and is not very efficient in that environment although it has a network version, Windows for Workgroup 3.11.

Windows 95 upgrades its earlier versions (Windows 3.x) in many ways. It has a new 3-D interface. It is mostly a 32- bit system although it has 16-bit components included for compatibility with Windows 3.x. Windows 95 does not need to have a separate DOS. It integrates all DOS services. A Windows 95 system runs in protected mode. This means that it speeds up the processors and provides more safety.
Windows 95 serves two purposes: It will move developers to the Win32 API and will ease the transition for users whose hardware is not yet ready to handle the demands of Windows NT.
Windows 95 offers better preemptive multitasking. Although for most things, cooperative multitasking is good. However, if users want to do several things simultaneously, they are going to find that preemptive multitasking provides smoother operation and better speed.
Because Windows 95 is based on Win32 and has borrowed some of NT's features, some people are confused over which Windows to use. Windows 95 is for anyone who has a lower capability computer that does not enable to use Windows NT. Windows 95 is likely to perform better than NT as a desktop system, especially when running older 16-bit Windows applications.

Advantages and Disadvantages

• Advantages: This operating system provides compatibility with existing Windows and DOS programs. It also offers compatibility with existing Windows and DOS device drivers. It works as in standalone computer and in networked environment for both desktop and mobile users. It supports Windows for Workgroups, Novell and UNIX-style networks.
  It is easier to learn and use, gives users better performance, has more capacity, integrates applications better, connects better, and crashes less than its predecessor, Windows 3.x.

• Disadvantages: Windows 95 still has limits from 16-bit components retained for backward compatibility with 16-bit application. It does not give much benefit to the 16-bit applications. To get benefits from Windows 95, users must upgrade their applications to 32-bit versions that support OLE and can interact directly with Windows 95's shell. It will cost users significantly.

Difference of 95 with Windows NT

Windows 95 has a different user interface with Windows NT. The interface of NT is much better. Windows 95 uses a different model for device drivers than NT. Thus, not all Windows 95 applications run on NT without modification, and vice versa. Windows 95 is a mix of 16- and 32-bit application programming interface, but NT is solely a 32-bit interface.

Window NT is a platform for 32-bit Windows applications. This is a powerful and one of the most advanced operating systems available today.
Windows NT was originally designed with big-system features. Beginning with version 3.5, Microsoft began repositioning Windows NT as a workstation and server operating system. It also has a sophisticated multiuser security system, so Windows NT performs excellently as a disk server. NT has support for network services useful to applications like client/server database engines. Still, all the features of Windows NT are suitable for use in demanding applications of desktop users.

Advantages and Disadvantages

• Advantages: Windows NT allows users to run all applications, including Windows applications, from the command line. It has better speed. Windows NT does not have arbitrary resource limits. Computer system reliability is improved by the result of this. It has the familiar Windows 3.x-style user interface, so users do not need to spend much time for learning. NT has a preemptive multitasking capability, and the users can multitask applications within their own memory spaces. It has much more reliable networking capability than that provided by Windows 3.x or Windows 95.

• Disadvantages: Windows NT is a platform for 32-bit Windows applications. 32- bit applications are not widely available yet. Still, 16-bit applications are prevailing in the software market. This operating system requires much resource. Windows NT workstation requires 12MB of memory when run on Intel 486/pentium computers (It runs in 8MB, but Microsoft recommends 12MB for NT to run adequately). Windows NT server requires 16MB. Windows NT system that is run on an RISC workstation also demands 16MB of memory. The NT requires at least 70MB of hard disk space only for the operating system. After all, this operating system requires too much for normal microcomputer users

OS/2 stands for Operating System 2. This is another operating systems for powerful microcomputers and networking. OS/2 was designed to avoid some of the most serious limitations of DOS. OS/2 runs in 4MB of memory, although it runs well in an 8MB system. It requires about 30MB of hard disk space. OS/2 WARP, the window version of OS/2, performs reasonably well in 4MB system and requires less disk space.
Users do not need to abandon DOS and Windows to try out OS/2. OS/2 provides a dual boot feature that allows users to boot up in either DOS or OS/2. OS/2 uses folders much like those on the Macintosh and on some UNIX GUIs.

Advantages and Disadvantages

• Advantages: It is not affected by requirements of DOS and Windows that certain device drivers live in the first 640KB of memory. Instead, OS/2 can load network adapter drivers, multimedia interfaces, CD-ROM software or video drivers into memory as required. While OS/2 works very nicely with the same FAT file system used by DOS, its HPFS has a number of benefits. It is significantly faster, it allows a long file name, and it supports disk drivers as large as 256 gigabytes.
  This operating system allows multitasking and dynamic data interchange. It also provides common graphical user interface with mainframes, minicomputers, and microcomputers by OS/2 WARP. OS/2 was developed to assist in the sharing of data and programs among several microcomputers. OS/2 solidly supports Novell Netware and TCP/IP. Most network interface cards are supported.

• Disadvantages: OS/2 Shell or WARP is similar to Windows, but is not identical. It may take users a while to adjust to some of the differences. The application programs developed specifically for OS/2 are not as many as those for Windows, although more and more application developers are going to converting and developing programs for OS/2 thesedays.

UNIX was originally developed in 1969 by K. Thompson, R. Canaday and D. Ritchie for minicomputers in the Bell Laboratories in the USA owned and run by AT& T. By the mid-1970s, UNIX had been introduced to University of California at Berkeley by Thompson, then widespread into an academic world. Most computer science departments of universities have been used UNIX. UNIX initially became popular in industry because for many years AT& T licensed the system to universities for a nominal fee. The effect of this was that UNIX was carried by recent computer science and engineering graduates to their new places of employment. Rapid commercialization of UNIX followed on from this. This rapid commercialization caused the lack of standards. Many hardware and software vendors developed their own versions.
After UNIX was widespread, it had been used by scientists and engineers. It is because of its scientific and technical orientation. It is less well known with business people. All that, however, is probably about to change. The reason is that with the arrival of very powerful microcomputers using the newer chips such as pentium and pentium-pro chips, UNIX has become a major player in the microcomputer world. The difficulty of learning is also about to change because of the graphical user interface.

This is a multiuser, multitasking operating system that runs on many different computer systems from microcomputer to mainframe, because UNIX is written in C programming language, which is a language designed for system-level programming. UNIX is consisted of a kernel, the file system, the user interface. The kernel is the heart of the operating system. The file system has a hierarchical directory method for organizing files on the disk and the shell.

Advantages and Disadvantages

• Advantages: UNIX is the portable operating system that can be used with many different computers from mainframe to microcomputer. The other operating systems such as DOS, Windows, Mac operating system, and OS/2 cannot be used for other systems. One of many strong features of UNIX is multitasking. UNIX allows users to run multiple programs simultaneously.
  UNIX also shares it among multiple users. UNIX is not restrained by the computer systems such as conventional memory as the DOS and OS/2 systems are. It can accomplish many operations that were formerly performed on minicomputers or mainframes. It is important, because industry can achieve the performance and benefits of large computers from microcomputers by using UNIX.
  Networking is another strong feature of a UNIX operating system. UNIX can be connected through several different kinds of equipment. It can share files among them.

• Disadvantages: Although UNIX can do many things, it can be difficult for novice microcomputer users to understand. This is a reason it has had a limited impact to date. UNIX was a minicomputer operating system used by programmers and computer science professionals some time before the rise of the microcomputer. This means that it has certain qualities making it useful to programmers - many supporting utility programs and documentation, for instance. Some of its features make it difficult for end users. However, it is about to change, because a set of standards for a UNIX GUI have come into use and most of the UNIX operating system incorporates graphical user interface.
  Limited application programs are another disadvantage for UNIX. UNIX off-the-shelf programs for microcomputers are limited. However, this situation is going to change, because many software vendors are rewriting DOS and Windows applications for UNIX.
  As stated earlier, there is not a standard for UNIX. This may be the biggest problem for the popularity of UNIX. The principal microcomputer versions are the AT& T UNIX System V, the UC Berkeley UNIX, and Xenix developed by Microsoft for a microcomputer version. AIX from IBM, Solaris, and Linux are other variants of UNIX. An application program written for one version of UNIX may not run on other versions.
  There is also not a standard GUI for many UNIXs. There were several attempts to combine the Sun, AT& T, and U.C. Berkeley versions of UNIX to produce a standard graphical user interface. The one was Open Look (Sun/Open Windows) by Sun, AT& T and Berkeley. Another graphical user interface was an OSF/Motif by the Open Software Foundation (OSF). OSF/Motif is now in severe disarray.

It uses a graphics screen that places familiar office objects on a display screen. Files, folders, programs, and disks are represented by icons. It has a hierarchical file system that lets users drag document icons into and out of folder icons. Folders can also contain other folders and so on.
In IBM computers and IBM compatible computers, software developers usually decide how they make a user interface. In contrast, Macintosh application developers usually conform to the Macintosh user interface. This consistent user interface makes users easy to learn new programs from the start. This also makes Macintosh operating system and its application programs indistinguishable.
The Macintosh user interface style has been adapted to many other operating systems. For example, OS/2 Presentation Manager and WARP, New Wave, most UNIX systems, and Windows look very similar to the Macintosh graphics user interface.
The Macintosh operating system has two major files. They are the System file and the Finder. The system file manages the user interface. Both files work together to achieve the operating system procedures such as formatting disks, copying files, erasing files, and running application programs.

Advantages and Disadvantages

• Advantages: The ease of use is the primary charm of the Macintosh. The graphics interface such as menus, screen display, and dialog boxes are quite more consistent across applications than they are in Windows. It also offers easy plug and play. When install a board in a Mac, users need to plug it into a slot, drag its driver icon into the System Folder, and reboot the computer.
  It provides long filenames, integrated program and file management, desktop icons, and shortcuts. It provides a high quality graphics processing that makes Macintosh popular for desktop publishing (Mac is the standard computer in the publishing industry). It has a great video architecture that allows users to add multiple monitors to a computer by adding another video board and hook up another monitor.
  The later versions of Macintosh operating system (System 7.x series) enable users to do multitasking. That is, multiple programs can run simultaneously, each sharing the CPU (cooperative multitasking like Windows 3.x). System 7.x allows applications programs to exchange and share data and commands with other application programs.
  It even provides built-in sound, SCSI, and Ethernet that allow users to work easily with multimedia. It has much better multimedia toolkit than Windows has. The IBM and compatible computers, PC, cannot match the Macintosh's toolkits for multimedia, and Windows multimedia applications do not work together as smoothly as their Macintosh counterparts.

• Disadvantages: The first disadvantage of the Macintosh platform is the incompatibility with DOS and Windows (PC) applications. This has been made Macintoshes less attractive to corporate users that want to have compatibility and connectivity within company and between companies. However, software (e.g., Insignia's SoftWindows) are now available for the Mac to allow it to run Windows on PowerMac although it runs slowly. This is a great utility for a Mac user who needs to run DOS or Windows applications occasionally. Another solution for this is the fact that networks connecting Macintoshes to PCs are available these days.

Window

A window was originally a general name of viewing area on a display screen provided by software. Many operating systems can provide multiple windows on a display screen. Under this environment, users usually can work several tasks with several application programs on a screen at the same time. Microsoft makes Windows the brand name of its operating system. They are Windows/286, Windows/386, Windows 3.x, Windows 95 and Windows NT. Users need to be careful not to think of only Microsoft's Windows has windows. Many operating systems such as OS/2 Presentation Manager, OS/2 WARP, many UNIX systems, and Macintosh operating system have windows.

XMS

It is an abbreviation of eXtended Memory Specification. This is an interface that allows DOS applications to use extended memory. This allows DOS applications to only allocate extended memory, but does not allow them to run in extended memory.

EMS

Expanded Memory Specification is a technique for expanding memory beyond one megabyte under DOS. EMS and XMS are different techniques to enlarge memory running under DOS. XMS is a normal memory beyond one megabyte on 286 and higher computers, but EMS is separate memory that can be installed in any computer system.

Win32 API

It is a 32-bit Windows Application Programming Interface. This enables applications to be more responsive, has larger document capacities, and handles CPU- intensive tasks more quickly than Win16 API. When a program marked with Windows 95 ready on the software package, it is designed using Win32 API.

Preemptive/Cooperative Multitasking

Preemptive multitasking means that one Windows application can get control of CPU without the knowledge of another Windows application. In contrast, Cooperative multitasking means that an application can assume it has full control until it yields to other applications. Many operating systems such as Windows NT, Windows 95, or OS/2 have preemptive multitasking function.

Resource Limit

Windows 3.x has three 64KB resource heaps that must be shared by all applications in the system. When those three heaps are exhausted by many applications, errors like "out of system resource" occur. Windows NT does not have that kind of limit.

HPFS

This refers a High Performance File System introduced with OS/2. The system handles larger disks, long file names, and can launch the program by referencing the data. It coexist with the existing FAT system.

FAT

FAT is an abbreviation of File Allocation Table that is the part of DOS and OS/2 file system. It keeps tracks of where the data is stored on a disk. It is a table with an entry for each cluster. The directory contains file ID that points to the FAT entries where the files start.

Linux

Linux is a great variant of UNIX. It has most of the features and, in some cases, better features of UNIX. Furthermore, it runs on lower end machines - 386- class system or higher with 8MB of memory. It requires only as small as 20MB of hard disk space to install it. It requires a CD-ROM drive. Users can get all these features at only $30 to $50 (Information: http://www.cdrom.com or http://www.morse.net). Users who are not decided to buy can even download Linux free from several ftp sites (e.g., sunsite.unc.edu, tsx-11.mit.edu, ftp.uu.net, and wuarchive.wustl.edu).

Application software consists of Programs that direct computers to perform specific information processing activities for end users. These programs are called application packages because they direct the processing required for a particular use, or application, which users want to accomplish. Thousands of application packages are available because there are thousands of different jobs end users want computers to do.

Kinds of Application Software

Application software includes a variety of programs that can be subdivided into general-purpose and application-specific categories.

General-Purpose Application Programs

General-purpose applications packages are programs that perform common information processing hobs for end users. For example, word processing programs, electronic spreadsheet programs, database management programs, graphics programs, communications programs, and integrated packages are popular with microcomputer users for home, education, business, scientific, and many other general purposes.
They are also known as productivity packages, because they significantly increase the productivity of end users. This packaged software is also called off-the-shelf software packages, because these products are packaged and available for sale. Many features are common to most packaged programs.

Application-Specific Software

Many application programs are available to support specific applications of end users. Business Application Programs: Programs that accomplish the information processing tasks of important business functions or industry requirements.
Scientific Application Programs: Programs that perform information processing tasks for the natural, physical, social, and behavioral sciences, engineering and all other areas involved in scientific research, experimentation, and development. There are so many other application areas such as education, music, art, medicine, etc.

The trend in computer application software is toward multipurpose, expert-assisted packages with natural language and graphical user interfaces. There are two major trends:

Off-The-Shelf Software Packages

There is a trend away from custom-designed one-of- a-kind programs developed by the professional programmers or end users of an organization.
Instead, the trend is toward the use of the "off-the-self" software package acquired by end users from software vendors. This trend accelerated with the development of inexpensive and easy-to-use productivity software packages for microcomputers, and it continues to grow.

Nonprocedural, Natural Languages

There is a major trend away from technical, machine-specific programming languages using binary-based or symbolic codes and from procedural languages, which use English-like statements and mathematical expressions to specify the sequence of instructions a computer must perform.
Instead, the trend is toward nonprocedural, natural languages that are closer to human conversation. This trend has accelerated with the creation of easy-to-use, nonprocedural fourth- generation languages (4GL). It continues to grow as developments in graphics and artificial intelligence produce natural language and graphical interfaces that make software packages easier to use.

Word Processing Packages

Word processing software is used to create, manipulate, and print documents. Documents can be any kind of text material. Some examples of documents are letters, memos, term papers, reports, and contracts.
The beauty of the computer word processor is that users can make any changes or corrections before printing out the document. Even after usersr document is printed out, users can easily go back and make changes. Users can then print it out again. Popular word processing packages include WordPerfect, MS-Word, and MacWrite. These word processing packages allow users to do the following interesting features:

• Word Wrap/Enter Key: One outstanding word processing feature is a word wrap. A word processor decides for Users and automatically moves the cursor to the next line. As users keep typing, the words "wrap around" to the next line. To begin a new paragraph or leave a blank line, users press the Enter key.

• Search/Replace: A search command allows users to find any wcircleord or number that users know exists in usersr document. When users search, the cursor will move to the first place where the item appears. The replace command automatically replaces the word users search for with another word. The search and replace commands are useful for finding and fixing errors.

• Block/Move: The portion of text users wish to move is a block. Users mark the block by giving commands that produce highlighting, a band of light over the area. The task of moving the block is called a block move. The block command may also be used to delete text or to copy chunks of text into another document.

• Margins: Margins may be justified to right, left or full (right and left at the same time) in the most word processing packages. That is, they may be evened up to the right, left or both side simultaneously.

• Centering/Emphasizing: Headings of a document may be centered. Words or phrases may be typed underlined or boldface (extra dark lettering) for emphasis.

• Spelling Checker: A spelling- checker program can check spelling errors in a document automatically.

• Thesaurus: This programs enable users to quickly find the right word or an alternative word by presenting users with an on-screen thesaurus.

• Mail Merge: This feature allows users to merge different names and addresses so that users can mail out the same form letter to different people.

• Desktop Publishing: Today's advanced word processing programs can perform desktop publishing capabilities. This feature enables users to mix text and graphics to produce newsletters and other publications of nearly professional quality.

• Outliner: Sometimes called idea processors. It helps users organize and outline usersr thoughts before users prepare a document or develop a presentation.

• Grammar/Style Checker: These programs can be used to identify and correct grammar and punctuation errors.

• Importing: Most of the programs have an importing feature. Files may be retrieved from nontext programs such as spreadsheets and graphics and added to the word processing program.

A spreadsheet is an electronic worksheet used to organize and manipulate numbers and display options for what-if analysis. The electronic spreadsheet has rows and columns stored in the computer's memory and displayed on its video screen.
Electronic spreadsheets allow users to try out various what-if kinds of possibilities. That is a powerful feature. Users can manipulate numbers by using stored formulas and calculate different outcomes.
A spreadsheet has several parts. The worksheet area of the spreadsheet has column headings across the top and row headings down the left-hand side. The intersection of a column and row is called a cell. The cell holds a unit of information. The position of a cell is called the cell address. A cell pointer (sprepdsheet cursor) indicates where data is to be entered or changed in the spreadsheet.
Popular electronic spreadsheet packages include Lotus 1-2-3, Quattro Pro, and Excel. Some common features of spreadsheet programs are as follows:

• Format: Column and row headings are known as labels. Usually a label is a word or symbol. A number in a cell is called a value. A label can be centered in the cell or positioned to the left or right. A value can be displayed to show decimal places, dollars, or percent (%). The number of decimal positions (if any) can be altered, and the width of columns can be changed.

• Formulas: The major benefit of spreadsheets is that users can manipulate data by using formulas. They make connections between numbers in particular cells.
• Recalculation: Recalculation is the most important feature of spreadsheets. If users change one or more numbers in usersr spreadsheet, all related formulas will recalculate automatically. By manipulating the values, users can use spreadsheet formulas to explore usersr options.

• Windows: The screen-sized area of a spreadsheet that users can view is called a window or a page. Only about 20 rows and 8 columns of a spreadsheet are visible on the video display screen at one time. The total size of the spreadsheet can be much larger.

• Graphic Data Display: Most spreadsheets allow users to present their data in graphic form. That is, users can display numerical information as pie charts or bar charts.

• 3-D Graphics: Most spreadsheet programs even permit users to display data in graphs and charts that have a three-dimensional look.

• Graphics on Worksheet: A new feature gives users the ability to place graphical elements such as lines, arrows, and boxes directly onto the worksheet. Users can create charts and graphs directly on the worksheet.

• Consolidation Feature: Data may be consolidated from several small worksheets into one large worksheet. Thus, users can work with small worksheets, which are more manageable, and summarize the data on a large worksheet.

• Dynamic File Links: Some software offers dynamic file links, which allow users to link cells in one worksheet file to cells in other worksheet files. Whenever a change occurs in one file, the linked cells in the other files are automatically updated.

A database is a large collection of data entered a computer system and stored for future use. The computerized information in the database is organized so that the parts that have something in common can be retrieved easily. Most DBMS packages can perform four primary tasks:

• Database Development: Define and organize the content, relationships, and structure of the data needed to build a database.

• Database Interrogation: Access the data in a database for information retrieval and report generation. A user can selectively retrieve and display information and produce printed reports and documents.

• Database Maintenance: Add, delete, update, correct, and protect the data in a database.

• Application Development: Develop prototypes of data entry screens, queries, forms, reports, and labels for a proposed application.

A database management package or database management system (DBMS) is a software package used to set up, or structure, a database. It is also used to retrieve information from a database. The top part of the figure is a menu. The entire list of member names and addresses is called a file. Each line of information about one member is called a record. Each column of information within a record is called a field.
Popular database management programs include dBASE, Paradox, and FoxPro. Database management packages have different features, depending on their sophistication. A principal feature of database management software for microcomputers are as follows:

• Retrieve/Display: A basic feature of all database programs is the capability to locate records in the file quickly. The program can search each record for a match in a particular field to whatever data users specify. The records can then be displayed on the screen for viewing, updating, or editing.
  
• Sort: Database management packages make it easy to change the order of records in a file. Normally, records are entered the database in the order they occur. There are many ways users can quickly rearrange the records in the file, such as by employees' last name or by their social security number.

• Calculate/Format: Many database programs contain built-in math formulas. In the office, for example, users can use this feature to find the highest or lowest commissions earned. Users can calculate the average of the commissions earned by the sales force in one part of the country. This information can be organized as a table and printed out in a report format.

• Customized Data-Entry Forms: A person new to the database program may find some descriptions for fields confusing. For example, a field name may appear as "CUSTNUM" for "customer number." However, the form on the screen may be customized so that the expression "Enter the customer number" appears for "CUSTOM." Fields may also be rearranged on the screen, and boxes and lines may be added.

• Professional-Looking Reports: A custom-report option enables users to design the elements users want in a report. Examples are the descriptions appearing above columns and the fields users wish to include. Users can even add graphic elements, such as a box or line, so that the printed report has a professional appearance.

• Program Control Languages: Most people using a database management program can accomplish everything they need to do by making choices from the menus. Many database management programs include a programming control language so that advanced users can create sophisticated applications.

A graphics program can display numeric data in a visual format for analytical or presentation purposes. Any other types of presentation graphics displays are possible. Draw and Input graphics packages support freehand drawing, while desktop publishing programs provide predrawn clip art graphics for insertion into documents. Popular business graphics packages are Harvard Graphics, Freelance, Corel Draw, and etc.
There are two types of graphics programs. Analytical graphics programs are used to analyze data. Presentation graphics programs are used to create attractive finished graphs for presentations or reports.

• Analytical Graphics: Analytical graphics make numerical data much easier to grasp than when it is as rows and columns of numbers. Graphics may take the form of bar charts, line graphs, and pie charts. The bar chart gives an instant visual profile of the some figures. The line graph shows a visual profile in another way. The pie chart shows the proportion of some figures as slices of pie. High-low graph shows a range, such as house prices.
  Most analytical graphics programs come as part of spreadsheet programs, such as Lotus 1-2-3 and Quattro-Pro. They are helpful in displaying economic trends, sales figures, and the like for easy analysis. Analytical graphics may be viewed on a monitor or printed out.

• Presentation Graphics: Users can use presentation graphics to communicate a message or to persuade other people, such as supervisors or clients. Thus, presentation graphics are used by marketing or sales people, for example.
  Presentation graphics look more sophisticated than analytical graphics, using color, titles, a three- dimensional look, and other features a graphic artist might use. High-end presentation graphics packages even include animation capabilities. These packages allow users to create and edit animated graphics on usersr microcomputer.

Communications software packages for microcomputers are also viewed as general-purpose application packages. These packages can connect a microcomputer equipped with a modem to a public and private network. Communications software enables a microcomputer to send and receive data over a telephone or other communications line.
Communications programs are used by all kinds of people inside and outside business. Examples are students doing research papers, travelers making plane reservations, consumers buying products, investors getting stock quotations, and economists getting government statistical data.
Communications programs give microcomputers a powerful feature, which is connectivity. Connections with microcomputers open a world of services. Popular communications software includes ProComm, Smartcom, and Crosstalk. Some common features of microcomputer communications programs are as follows:

• Data Banks: With a communications program, users can access enormous computerized databases - data banks of information. Some of these, such as Dialog, resemble huge electronic encyclopedias.

• Message Exchanges: Communications programs enable users to leave and receive messages on electronic bulletin boards or to use electronic-mail services. Electronic bulletin boards exist for people interested in swapping all kinds of software or information.
  Many organizations now have electronic mailboxes. For instance, users can transmit a report users have created on usersr word processor to a faraway company executive or to a college instructor.

• Financial Services: With communications programs, users can look up airline reservations and stock quotations. Users can order discount merchandise and even do home banking and bill paying.

Integrated packages combine the abilities of several general-purpose applications in one program. Integrated software is an all-in-one application package that includes word processing, spreadsheet, database manager, graphics, and communications. An integrated package works together and shares information from one program with another.
Integrated packages were developed to solve the problems caused by the inability of individual programs to communicate and work with common files of data.

Some integrated packages require significant amounts of memory and may compromise on the speed, power, and flexibility of some of their functions to achieve integration. Powerful microcomputers available these days, however, allow users to accomplish all their works without sacrificing computers' speed and flexibility.
What happens if users want to take the data in one program and use it in another? Suppose users want to take information stored in the database manager and use it in a spreadsheet. This is not always possible with separate application packages, but it is with integrated software.
With an integrated package, users can use the database manager to pull together relevant facts. An example of such facts might be the annual membership fees for a sports club for different years. Users can then use the spreadsheet to compare these membership fees. Users can use the word processing program to write a memo about these membership fees for different categories of members. Users can use this program to merge into the memo totals from the spreadsheet. Finally, users can use the communications program to send the memo to another computer.
Some popular integrated packages are Works, First Choice, Symphony, Enable, Framework, SmartWare 11, Microsoft Office, and Perfect Office. End users who are just beginning to learn about application software find integrated packages quite helpful. These packages can easily exchange data between programs, and they share a common structure. These factors make them easy to learn and convenient to use.

What-If Analysis Example

A bookstore manager can figure out whether the business will make a profit or loss by projecting the cost of books and computer software, clothes, stationery, and other sales over a six-month period. The manager can then subtract expenses from sales. Expenses might include such things as payroll for employees, lease of bookstore space, and purchases of books and other supplies. If the expenses are too high to produce a profit, the manager can experiment on the screen with reducing some expenses. For example, the number of employees and therefore payroll costs might be reduced.