Basics of Computers: Classification, Applications, Advantages and Limitations


By: Site Engineer, Staff

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Classification of Computers

With the advent of computers, many office and home appliances now have in-built computerized components that enable them to function autonomously or semi-autonomously. Such systems are said to be computerized.

Although, we generally do not call them computers they have in-built computers which are programmed to perform some specific and specialized tasks. Such computerized systems are to be found these days in refineries and other industrial installations and equipment can be (e.g., the brain box), camera, airplanes, wristwatches, video and television sets, compact disc players and mobile phones. However, we are concerned here with computers that are intended to serve a wide range of purposes including word processing, data analysis graphic designs and playing games and music. They are also called general-purpose computers or simply, computers.

General-purpose computers may be classified based on their:

  1. Capacities
  2. Prices
  3. Sizes
  4. Speed
  5. Uses

The different classes are:

  1. Microcomputers: The miniaturization of processors, thus making it possible to build small-sized processors, which gave birth to the microprocessor. Thus, it is now common to have personal computers which given the size, capacity, cost, and functions are suitable for individual home and office uses.

In this category are desktops (which are suitable for use on office tables), laptops (which are small and light enough to be placed and used on the user’s lap while in transit by air rail or road) and the so-called palmtop. This palmtop is suitable for managers and business persons who are constantly on the move. We should not underrate these computers because of their small sizes. Some palmtops have more main memory, disk space, and speed than some desktops. In any case, microcomputers are generally powerful enough to deal with the complexities of the operations of a typical office.

  1. Minicomputers: This lies between microcomputers and mainframes in terms of size and capacity. Since the advent of microcomputers, they have become much less popular and are generally now restricted to large businesses that handle a large volume of very complex activities.
  2. Mainframe Computers: These are large-scale machines designed to handle more demanding and complex computations. They are more expensive than microcomputers and computers.
  3. Supercomputers: They are the fastest computers. They are used for computations which involve massive data, millions of instructions, a lot of storage space and complex calculations. They are the most expensive type. They are commonly used for scientific calculations, weather forecasts, oil explorations and special effects in scientific films.

Advantages of the Computer

The growing and awesome popularity of the computer is largely attributable to the immense benefits that it offers. The most outstanding of the benefits is its speed; cost-effectiveness, accuracy, versatility and its ability to handle complex jobs. It is also quite flexible.

A computer works several hundred times as fast as a genius doing the same computations manually. For instance, using a spreadsheet or a database application package a computer can compute the payroll of all company employees within seconds once the data have been fed in and the command given.

Similarly, an electronic mail can be sent from say Nigeria and delivered to its destination in, say Japan or China within a few seconds. Such is the mega speed of the computer.

Computers have features to handle computation with a high degree of accuracy and error-free services. As a general rule, a computer will not make a computational error. It will give you the level of precision and accuracy that you request.

Therefore, it is quite useful for making sensitive calculations such as those relating to space travel, military operations, and medical operations. The reason the computer can achieve this level of accuracy is that the instructions are carefully written and well tested before they are commercialized.

General-purpose computers are versatile and flexible. They are said to be versatile because they can handle a variety of tasks. Flexibility relates to their ability to handle “what if” questions or the ability to provide answers to questions based on different scenarios or sets of assumptions.

To illustrate this, a computer may be requested to determine the total earnings of a group of employees based on one set of assumptions about overtime rates, other allowances, several days worked and bonus earned.

If, however, a different set of assumptions is now made, the computer will have no difficulty whatsoever to re-computing the desired set of answers without any form of boredom.

A computer can easily handle complex computations involving a large volume of data. Neither the volume nor the complexity will enhance the likelihood of errors except those relating to data entry which is human.

Finally owning and using computers are good for the image of the small firm. Especially in a developing country where everything including owning a mobile phone is a status symbol, owning computers signifies to both employees and external people that the company is viable, innovative, progressive and good to do business with.

Limitations Associated with Computers

The cliché, “garbage in garbage out” refers to “the quality of the output is governed by the input”. In other words, it is referred to as the fact that a computer works with whatever set of instructions and data the user submits to it. If they are garbage, the computer will obey the instructions to the letter, using the data provided by the user. It will go ahead and report the results dispassionately, even if they are garbage.

If we submit the wrong bonus rates to the computer, it will apply chose rates. Unless the package had been informed earlier that the rate must lie within a certain range, the computer would have no means of verifying the entries. It is for this reason that we say that the computer is a zombie who will do whatever it is instructed to do provided the instructions and data can be fed into it, using a language it understands. It is in this sense that the computer is sometimes referred to as an “idiot”.

It is generally believed in Nigeria that computers are expensive to acquire, install and use, especially from small business. In at least two respects, this is not exactly correct.

As of the year 2003, one could acquire a complete system with a printer for N100,000 (one hundred thousand naira) only. Given the immense benefits, this is a relatively small amount. The second way to evaluate this cost is to compare it with the other options available. Handling some business operations manually rather than computerizing them can be quite expensive and inefficient in terms of the associated delays, inconvenience, poor quality output, customer dissatisfaction, and image.

Computer fraud is a fact of life. Whereas the computer cannot itself commit fraud, fraudsters can take advantage of its facility and the computer-illiteracy of the entrepreneur and other employees to perpetrate fraud.

We sometimes hear of computer-aid bank frauds running into millions of naira. Although manual (uncomputerized) operations are also vulnerable to fraud, computer-aided frauds are usually easier to perpetuate and often run into much larger amounts.

However, it is heartening to know that security checks and balances can be built into computer programs or computer systems to prevent unauthorized persons from having access to sensitive data. It is also possible to make fraud difficult for those who have legitimate or authorize access to the system.

Another problem related to computer fraud is the or insecurity of data stored or transmitted via the computer. Hackers, crackers, and viruses can attack computer contents and tamper with or corrupt the data and the programmes. Again, it is easy to protect against these threats to data and programmes.

Two additional problems that are peculiar to developing countries are the unreliability of electric power supply and widespread computer illiteracy even among otherwise well-educated business owners, entrepreneurs, managers, workers, suppliers, and customers.

In spite of the several limitations just discussed above, we do not doubt that the computer will become an inevitable ally of every business person. Even in Nigeria and other developing countries, it will be difficult if not impossible to operate any serious business without computers in the future.


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