To be read after the Unit 15

Text 1. Types of Computers

The types of computers range from the Hybrid to the Analog types. The computers you come across in the daily course of your day range from laptops, palmtops and towers, to desktop computers, to name a few. But the very word «computers» reminds one of the desktop computers used in offices or homes. Different categories of computers have been devised in keeping with our varied needs.

According to the classification based on operational principle the types of computers: analog and hybrid.

Analog Computers: The Analog computer is almost an extinct type of computer these days. It is different from a digital computer in respect that it can perform numerous mathematical operations simultaneously. It is also unique in terms of operation as it utilizes continuous variables for the purpose of mathematical computation. It utilizes mechanical, hydraulic, or electrical energy or operation.

Hybrid computers: These types of computers are, as the name suggests, a combination of both Analog and Digital computers. The Digital computers which work on the principle of binary digit system of «0» and «1» can give very precise results. But the problem is that they are too slow and incapable of large scale mathematical operation. In the hybrid types of computers the Digital counterparts convert the analog signals to perform Robotics and Process control.

Apart from this, computers are also categorized on the basis of physical structures and the purpose of their use. Based on capacity, speed and reliability they can be divided into three categories of computers:

1. The Mainframe Computer – These are computers used by large organizations like meteorological surveys and statistical institutes for performing bulk mathematical computations. They are core computers which are used for desktop functions of over one hundred people simultaneously.

2. The Microcomputer – These are the most frequently used computers better known by the name of «Personal computers». This is the type of computer meant for public use. Other than Desktop Computer the choice ranges as follows: Hand-held (HPC), PDA, Tablet PC, Laptop, Desktop, Tower, Workstation.

A desktop is a PC that is not designed for portability. The expectation with desktop systems is that you will set the computer up in a permanent location. Most desktops offer more power, storage and versatility for less cost than their portable brethren.

Laptops, also called notebooks, are portable computers that integrate the display, keyboard, a pointing device or trackball, processor, memory and hard drive all in a battery-operated package slightly larger than an
average hardcover book.

Palmtops, more commonly known as Personal Digital Assistants (PDAs), are tightly integrated computers that often use flash memory instead of a hard drive for storage. These computers usually do not have keyboards but rely on touchscreen technology fox user input. Palmtops are typically smaller than a paperback novel, very lightweight with a reaso-nable battery life. A slightly larger and heavier version of the palmtop is the handheld computer.

A tablet PC is a notebook or slate-shaped mobile computer, first introduced by Pen Computing in the early 90s with their PenGo Tablet Computer and popularized by Microsoft. Its touchscreen or graphics
tablet/screen hybrid technology allows the user to operate the computer with a stylus or digital pen, or a fingertip, instead of a keyboard or mouse. The form factor offers a more mobile way to interact with a computer. Tablet PCs are of notebooks are impractical or unwieldy, or do not provide the needed functionality.

A workstation is a desktop computer that has a more powerful processor, additional memory and enhanced capabilities for performing a special group of task, such as 3D Graphics or game development.

3. The Mini computer – Mini computers like the mainframe computers are used by business organization. The difference being that it can support the simultaneous working of up to 100 users and is usually maintained in business organizations for the maintenance of accounts and finances.

Yet another category of computer is the Super Computers. It is somewhat similar to mainframe computers and is used in economic forecasts and engineering designs. Today life without computers is inconceivable. Usage of different types of computers has made life both smooth and fast paced.