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Chapter 6Computer Software

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Manager’s View

Manager’s need to understand various kinds of computer software - makes the hardware work for you.

Understand the three broad categories of software and their uses:– Systems Software.– Application Software.– Development Software.

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Management Concerns

Concern with site licensing versus installation on single workstations or servers.

Cost of upgrading hardware when new software is acquired.

Decision to build in-house versus buying a commercial package.

Developing company software standards.

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Systems Software Interfaces between computer system and

application programs--written by systems programmers.– Operating Systems.– Communications Software.– Database Management Systems Software.– Other System Software.

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Operating Systems

Manages/controls computer resources and peripherals, allocates memory, communicates to the computer operator.

Supervisory Programs: manages resources. Job Management Programs: schedule jobs. I/O Management Programs: handle input

and output resources.

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Resource Management Multiprogramming: more than one program in

memory at a time. Timesharing: system moves from one program to

another rapidly - like multiprogramming. Multiprocessing: two or more CPUs working

together sharing memory and peripherals. Parallel Processing: two or more CPUs

completing a single program. Virtual Storage: moving data to hard disk

temporarily.

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Communications Software

An extension of the operating system. Relieves operating system of the task of

controlling peripherals.– Communicates with remote terminals.– Monitors lines and equipment.– Manages communications traffic.

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Application Software

Performs specific functions, such as payroll; developed by application programmer.

Custom vs. Commercial: built in-house versus purchased as canned programs.

Shareware and Freeware: inexpensive sources of off-the-shelf application/systems utility programs.

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Application Software (Cont.)

Application Program Library: the library of application programs available for a specific operating system.

Portability: version for many different operating systems; can be converted easily.

Single-User/Multiuser Programs: e.g., a word processing document that can be updated by several users simultaneously.

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Application Software (Cont.)

Categorizing Application Software by Use:– General purpose software: used by people in

different industries.– Functionally-specific software: designed for

major functions such as financial analysis.– Industry-specific software: e.g., job estimating

software for the construction industry.

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Application Software (Cont.)

Desktop Suites: a family of packages such as Microsoft Office 97.– Word Processing Software: includes samples.– Spreadsheet Software: includes templates.– Database Management Software: sample

databases.– Presentation Graphics: includes sample slides.– Add-On Software: e.g., ichat for the net.

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Development Software

Allows programs and IS personnel to create custom software for specific types of jobs.

Programming Languages: used by application programmers.

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Programming Languages

Machine Languages: lowest level language. Assembly Languages: fast, but difficult to

learn. Third-Generation Languages: procedural--

tell computer exactly how to do tasks. Fourth-Generation Languages: non-

procedural--tell computer what to do, not how to do it.

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Selecting Microcomputer Software

Step 1: Identifying Your Application Needs. Step 2: Seeking the Right Software: check with

trade associations; contact software companies; consult software databases; use the Internet; examine computer magazines; contact consultants.

Step 3: Choosing the Right Software: compare with your application requirements.

Step 4: Selecting the Right Hardware. Step 5: Choosing a Software Vendor: look for

established vendors with technical support.