Business Information SystemsChapter 5

IntroductionSoftware fills the communication gap between

humans with problems to solve and computers that can only understand zeros and ones.

The three major categories of software are: Compilers and other translator programs, which

allow programmers to create other software. Software applications, which serve as

productivity tools to help computer users solve problems.

System software, which coordinates hardware operations and does behind-the-scenes work the computer user seldom sees.

5.1 PROCESSING WITH PROGRAMSAlthough computers are commonly called “smart

machines” or “intelligent machines,” a typical computer is capable of doing only the most basic arithmetic operations and a few simple logical comparisons. Computers seem smart because they can perform these operations and comparisons quickly and accurately.

An algorithm is a set of step-by-step procedures for accomplishing a task. A computer program generally starts as an algorithm written in English or some other human language. A programmer’s job is to turn the algorithm into a program by adding details, hammering out rough spots, testing procedures, and correcting errors.

5.1.2 The Language of Computers Every computer processes instructions in a native

machine language. Machine language uses numeric codes to represent the most basic computer operations—adding numbers, subtracting numbers, comparing numbers, moving numbers, repeating instructions, and so on.

Today most programmers use programming languages like BASIC and C that fall somewhere between natural human languages and precise machine languages. For a computer to understand a program written in one of these languages, it must use a compiler or other translator program to convert the English-like instructions to the zeros and ones of machine language.

The Language of Computers- continuedAs translators become more sophisticated,

programmers can communicate in computer languages that more closely resemble natural languages—the languages people speak and write every day.

Most tasks that required programming two decades ago can now be accomplished with easy-to-use software applications—tools like word processors, spreadsheets, and graphics programs.

5.2.1 Consumer ApplicationsThe differences between buying computer software and

music software (CDs or cassettes) are: A computer software package generally includes printed

documentation—tutorial manuals and reference manuals that explain how to use the software. Most modern software packages have some kind of on-line documentation.

Most software companies continually work to improve their products by removing bugs and adding new features.

A computer software buyer must be concerned with compatibility.

According to the warranties printed on many software packages, the applications might be worthless even if you have compatible hardware and software.

When you buy a typical computer software package, you’re not actually buying the software. Instead you’re buying a software license to use the program on a single machine. Virtually all commercially marketed software is copyrighted, so it can’t be legally duplicated for distribution to others; some disks (mostly games) are physically copy-protected, so they can’t be copied at all.

In general, most successful software products share two important characteristics.

Most successful software applications are built around visual metaphors of real-world tools.

Most popular computer applications are successful because they extend human capabilities in some way, allowing users to do things that can’t be done easily, or at all, with traditional tools.

5.2.2 Integrated Applications and Suites: Software BundlesWhile most software packages specialize in a

particular application—word processing, graphics, or whatever—integrated software packages include several applications designed to work well together and they generally include at least these six application types:

word processing database spreadsheet graphics telecommunications personal information management (PIM) modules

The parts of an integrated package may not have all the features of their separately packaged counterparts, but integrated packages still offer several advantages:

They cost considerably less than the total cost of purchasing individual programs that perform all of the separate functions.

They apply a similar look and feel to all of their applications, so users don’t need to memorize different commands and techniques for doing different tasks.

They allow quick and easy transfer of data between applications. Many include interapplication communication features, so changes created in one application are automatically reflected in other applications.

5.2.3 Vertical-Market and Custom SoftwareApplications designed specifically for a

particular business or industry are sometimes called vertical-market applications. Vertical-market applications tend to cost far more than mass-market applications, because companies that develop the software have very few potential customers through which to recover their development costs. In fact, some custom applications are programmed specifically for single clients.

5.3 SYSTEM SOFTWARE: THE HARDWARE-SOFTWARE CONNECTION5.3.1 What the Operating System Does Virtually all general-purpose computers today

depend on an operating system (OS) to keep hardware running efficiently and to make the process of communication with that hardware easier. The operating system, as the name implies, is a system of programs that perform a variety of functions, including:

Communicating with peripherals. Coordinating concurrent processing of jobs. Large, multi-user computers often work on several

jobs at the same time - a technique known as concurrent processing. State-of-the-art parallel processing machines use multiple CPUs to process jobs simultaneously.

If a PC has multitasking capabilities, the user can issue a command that initiates a process and continue working with other applications while the computer follows through on the command.

Memory management. Resource monitoring, accounting, and

security. Program and data management. Co-ordinating network communications.

5.3.2 Utility Programs Utility programs serve as tools for doing system

maintenance and some repairs that aren’t automatically handled by the operating system.

Where the Operating System Lives Some computers—mostly game machines and

special-purpose computers—store their operating systems permanently in ROM (read-only memory) so they are ready to go to work as soon as they are turned on. But because ROM is unchangeable, these machines can’t have their operating systems modified or upgraded without hardware transplants.

5.4 THE USER INTERFACE: THE HUMAN-MACHINE CONNECTION As software evolves, so does the user interface—the

look and feel of the computing experience from a human point of view.

Some popular user interfaces are: MS-DOS, the operating system that’s standard

equipment in millions of IBM-compatible computers (computers that are functionally identical to an IBM personal computer and therefore capable of running IBM-compatible software).

Apple’s Macintosh, the most popular alternative to IBM-compatible computers.

Microsoft Windows, software that provides a Macintosh-like user interface for IBM-compatible computers.

5.4 THE USER INTERFACE: THE HUMAN-MACHINE CONNECTION As software evolves, so does the user interface—the

look and feel of the computing experience from a human point of view.

Some popular user interfaces are: MS-DOS, the operating system that’s standard

equipment in millions of IBM-compatible computers (computers that are functionally identical to an IBM personal computer and therefore capable of running IBM-compatible software).

Apple’s Macintosh, the most popular alternative to IBM-compatible computers.

Microsoft Windows, software that provides a Macintosh-like user interface for IBM-compatible computers.

5.4.3 Why WIMP Won Graphical user interfaces with windows,

icons, menus, and pointing devices (sometimes called WIMP) offer several clear advantages from the user’s point of view:

They’re intuitive They’re consistent They’re forgiving They’re protective They’re flexible

Example of WIMP Interface

In the picture above notice that all the menus contain icons and everything can be selected by a mouse pointer think about your first cell phone, the Nokia 3310 was it as user friendly as current phones!

5.4.4 Multiple User Operating Systems: UNIX and Linux UNIX, developed at Bell Labs in the time

before PCs, allows a timesharing computer to communicate with several other computers or terminals at once. UNIX is a command-line, character-based operating system at heart, although several versions have shells with graphical interfaces.

Example of Linux Interfacenotice the picture below looks like windows but is actually a Linux operating system!

End of Chapter FIVE