Sources of software

Proprietary Software

Is a computer software which is legal property of one party. The terms of use for other parties is defined by contracts or licensing agreements.

Advantages of proprietary software

•         You can get exactly what you need in terms of reports, features etc.

•         Being involved in development offers a further level in control over results.

•         There is more flexibility in making modifications that may be required to counteract a new initiative by a competitor or to meet new supplier or customer requirements. A merger with another firm or an acquisition will also necessitate software changes to meet new business needs.

Disadvantages of proprietary software

•         It can take a long time and significant resources to develop required features.

•         In house system development staff may become hard pressed to provide the required level of ongoing support and maintenance because of pressure to get  soft ware

Off-the-Shelf Software

Off-the-shelf is a term for software or hardware, generally technology or computer products that are ready-made and available for sale, lease or license to the general public. Advantages of off-the-shelf software

-          The initial cost is lower since the software firm is able to spread the development costs over a large number of customers.

-          There is lower risk that the software will fail to meet the basic business needs

-          You can analyze existing features and performance of the package

-          Package is likely to be of high quality since many customer firms have tested the software and helped identify many of its bugs.

Disadvantages of off-the-shelf software

-          An organization may have to pay for features that are not required or never used.

-          The software may lack important features, thus requiring future modifications or customization. This can be very expensive because users must adopt future releases of the software.

-          Software may not match current work processes and data standards. 

Application software is further classified into general-purpose software and applications which include:

-          Word processing – Create, edit and print text documents, e.g. MS Word and Word Perfect.

-          Spreadsheets – Provide a wide range of built-in functions for statistical, logical, financial, database, graphics, data and time calculations, e.g. Lotus 1-2-3, Excel and Quattro Pro.

-          Database management systems (DBMS) – Store, manipulate and retrieve data. e.g. Access, FoxPro and dBase.

-          Online Information Services – Obtain a broad range of information from commercial services. e.g. America Online and CompuServe

-          Communications - Ms Outlook for email

-          Browsers e.g Internet Explorer and Eudora

-          Graphics – Develop graphs, illustrations and drawings. e.g. PaintShop, FreeHand and Corel

-          Project Management – Plan, schedule, allocate and control people and resources needed to complete a project according to schedule. e.g. Project for Windows and Time Line.

-          Financial Management – Provide income and expense tracking and reporting to monitor and plan budgets, e.g. Quicken

-          Desktop publishing - used to create high-quality printed output including text and graphics; various styles of pages can be laid out; art and text from other programs can also be integrated into published pages, e.g. PageMaker and Publisher. - Presentation packages like MS PowerPoint

Note

A software suite, such as Microsoft Office, offers a collection of powerful programs including word processing, spreadsheet, database, graphics among others. The programs in a software suite are designed to be used together. In addition, the commands, t icons and procedures are the same for all programs in the suite.

PROGRAMMING LANGUAGES

Programming languages are collections of commands, statements and words that are combined using a particular syntax, or rules, to write both systems and application software. This results in meaningful instructions to the CPU.

Generations of programming languages

Machine Language (1st Generation Languages)

A machine language consists of binary digit, that is, zeroes (0) and ones (1). Instructions and addresses are written in binary (0,1) code. Binary is the only “language” a CPU can understand. The CPU directly interprets and executes this language, therefore making its execution of instructions fast. Machine language programs directly instructed the computer hardware, so they were not portable. That is, a program written for computer model A could not be run on computer model B without being rewritten. All software in other languages must ultimately be translated down to machine language form. The translation process makes the other languages slower.

Advantage

•       The only advantage is that programs of machine languages run very fast because no translation program is required for the CPU.

Disadvantages

•       It is very difficult to programs in machine language. The programmer has to know details of hardware to write the program.

•       The programmer has to remember a lot of codes to write a program, which sometimes result in errors.

•       It is difficult to debug a program.

Assembly Language (2nd Generation Languages)

Uses symbols and codes instead of binary digits to represent program instructions. It is a symbolic language meaning that instructions and addresses are written using alphanumeric labels that are meaningful to the programmer.

The resulting programs still directly instruct the computer hardware. For example, an assembly language instruction might move a piece of data stored at a particular location in RAM into a particular location on the CPU. Therefore, like their first generation counterparts, second generation programs were not easily portable.

Assembly languages were designed to run in a small amount of RAM. Furthermore, they are low level languages; that is the instructions directly manipulate the hardware. Therefore, programs written in assembly language execute efficiently and quickly. As a result, more systems software is still written using assembly languages.

The language has a one-to-one mapping with machine instructions but has macros added to it. A macro is a group of multiple machine instructions, which are considered as one instruction in assembly language. A macro performs a specific task, for example adding and subtracting. A one-toone mapping means that for every assembly instruction, there is corresponding single or multiple instructions in machine language.

An assembler is used to translate the assembly language statements into machine language.

Advantages:

-          The symbolic programming of Assembly Language is easier to understand and saves a lot of time and effort of the programmer.

-          It is easier to correct errors and modify program instructions.

-          Assembly Language has the same efficiency of execution as the machine level language This is because this is a one-to-one translator between assembly language program and its corresponding machine language program.

Disadvantages:

-          One of the major disadvantages is that assembly language is machine dependent. A program written for one computer might not run in other computers with a different hardware configuration.

High-level languages (3rd Generation Languages)

Third generation languages are easier to learn and use than were earlier generations. Thus programmers are more productive when using third generation languages. For most applications, this increased productivity and compensates for the decrease in speed and efficiency of the resulting programs. Furthermore, programs written in third generation languages are portable, that is, a program written to run on a particular type of computer can be run with little or no modification on another type of computer. Portability is possible because third generation languages are “high-level languages”; that is, instructions do not directly manipulate the computer hardware.

Third generation languages are sometimes referred to as “procedural” languages since program  instructions, must give the computer detailed instructions of how to reach the desired result. High-level languages incorporated greater use of symbolic code. Its statements are more English– like, for example print, get and while. They are easier to learn but the resulting program  is slower in execution. Examples include Basic, Cobol, C and Fortran. They have first to be compiled (translated into corresponding machine language statements) through the use of compilers

Advantages of High Level Languages

-          Higher level languages have a major advantage over machine and assembly languages since they  are easy to learn and use.

-          Are portable

Fourth Generation Languages (4GLs)

Fourth generation languages are even easier to use, and more English-like, than are third generation languages. Fourth generation languages are sometimes referred to as “nonprocedural”, since programmes tell the computer what it needs to accomplish, but do not provide detailed instructions as to how it should accomplish it. Since fourth generation languages concentrate on the output, not procedural details, they are more easily used by people who are not computer specialists, that is, by end users.

Many of the first fourth generation languages were connected with particular database management systems. These languages were called Query Languages since they allow people to retrieve information from databases. Structured query language, SQL, is a current fourth generation language used to access many databases. There are also some statistical fourth generation languages, such as SAS and SPSS.

Some fourth generation languages, such as Visual C++, Visual Basic, or PowerBuilder are targeted to more knowledgeable users, since they are more complex to use. Visual programming languages, such as visual basic, use windows, icons, and pull down menus to make programming easier and more intuitive.

Object Oriented Programming

First, second, third and fourth generation programming languages were used to construct programs that contained procedures to perform operations, such as draw or display, on data elements defined in a file.

Object oriented programs consist of objects, such as a time card, that include descriptions of the data relevant to the object, as well as the operations that can be done on that data. For example, included in the time card object, would be descriptions of such data such as employee name, hourly rate, start time and. The time card object would also contain descriptions of such operations as calculating total hours worked or calculating total pay.

Language translators

Although machine language is the only language the CPU understands, it is rarely used anymore since it is so difficult to use. Every program that is not written in machine language must be translated into machine language before it can be executed. This is done by a category of system software called language translation software. These are programs that convert the code originally written by the programmer, called source code, into its equivalent machine language program, called object code.

There are two main types of language translators: interpreters and compilers.

Interpreters

While a program is running, interpreters read, translate, and execute one statement of the program at a time. The interpreter displays any errors immediately on the monitor. Interpreter are very useful for people learning how to program or debugging a program. However, the line-by-line translation adds significant overhead to the program execution time leading to slow execution.

Compilers

A compiler uses a language translation program that converts the entire source program into object code, known as an object module, at one time. The object module is stored and it is the module that executes when the program runs. The program does not have to be compiled again until changes are made in the source code.

Software trends and issues

Open source software coming to the scene: This is software that is freely available to anyone and can be easily modified. The use of open source software has increased dramatically due to the World Wide Web. Users can download the source code from web sites. Open source software is often more reliable than commercial software because there are many users collaborating to fix problems. The biggest problem with open source software is the lack of formal technical support. However, some companies that package open source software with various add-ons and sell it with support are addressing this. An example of this is Red Hat Linux operating system.

ICT PERSONNEL AND INFORMATION COMMUNICATION TECHNOLOGY HIERARCHY.

The organisation of ICT department

ICT Department functions

a)    Development, ongoing operation and maintenance of information systems

b)    Advisor to ICT users throughout the organisation

c)    Catalyst for improving operations through system enhancements/ new systems development

d)    Co-ordinating systems integration in the organisation.

e)    Establishing standards, policy, and procedures relating to ICT.

f)     Evaluating and selecting hardware and software.

g)    Co-ordinating end-user education.

Officers in ICT department

•       IT Manager/Director

•       Systems analysts

•       Programmers - system and applications

•       Database administrator

•       Network administrator

•       Librarian