An analog machine measures a continuous flow (1, 2, 3, 4, etc.) using analog signals. Analog signals are commonly used in phones, radios, television transmissions Gasoline stations of motor vehicles, and a vehicle speedometer. Analog computers are also called special-purpose computers. A special computer is designed to serve a function or some related tasks. On the other hand, digital computers (general use) can be loaded from making many different tasks. In digital computers, the user tells the computer what to do with a program.
Computer classes
Computers are also classified according to size. The large computers are subdivided into three groups (classes): Supercomputers, central computers, and minicomputers. Nowadays, smaller computers(Personal Computer) have taken the characteristics and capabilities of larger computers. The division line between classes is no longer well defined. Also, these Classes of Computers can be also termed as Types of computers.
Types of Computers
Supercomputers
Supercomputers are the most powerful, fastest, and Expensive Computer. Can process information at 1.2 billion per second and can make a contribution of more than 10,000 individual workstations. They have many processors and they cost millions of dollars.
A Supercomputer is Applied in nuclear weapons research, atomic bombs, finding oil, earthquake prediction, and sciences field where a lot of calculations must be done.
Mainframe computer
A mainframe computer is usually slower, less powerful, and less expensive than a super-computer, but they cost hundreds of thousands of US dollars. It can also have many processors.
Minicomputers
Minicomputers are smaller than the mainframe and usually work at 16-bit and 32-bit words. A minicostay can process data to several hundred thousand dollars to more than one million instructions per second. They are mainly used for time-sharing and are strongly used in companies, universities, scientific laboratories, research groups, engineering companies, industrial and manufacturing factories.
Microcomputer
Desktop
Computer Tower case ComputerA microcomputer is very small and cheaper than the mini-computer and the mainframe computers. The essential differences between micro-computers and the mainframe or minicomputers are that the microcomputers have a smaller and less power memory, are also physically smaller, and make it possible to reach fewer devices.
Microcomputers occur from different shapes such as desktop computers, turn case computers, laptops, and handheld palm computers. The laptop and the pocket palm are usually smaller, light,er and use the battery so they are portable. Palm computers are usually called Personal Digital Assistants (PDAs).
Personal computer
The personal computer (PC) is for personal use, as opposed to the server, which is used by more people simultaneously, from different locations, often through terminals. The laptop or tablet PC is used by people who need to travel or get around with a computer. Data entry into laptops is done via the attached keyboard and mouse pad while data entry on the tablet PC is done via the touch screen. A laptop or tablet can be used without a power connection, so it is necessary to recharge the batteries regularly.
Server and client computers
The term server refers to the function of a computer rather than a specific type of computer. A server manages a network of computers. It manages the sharing of equipment such as printers and communication between computers on the network. For such tasks, a computer should perform a little better in terms of power, memory, storage, and communication speed. A client computer is a computer that accesses the computing resources of the server. Normally, client computers have lower compute capacity specifications than the server.
Computer Capacities and Limitations
Computer capabilities
There are three important aspects to computer capabilities: speed, storage, and accuracy. These characteristics distinguish the computer from other computing devices. Since the computer is an electronic device, it performs its calculations by electrical means. A consequence of this characteristic is speed. So a computer does its calculations at electronic speed. A job that human beings can do in a year or two, the computer can do the same in seconds. The processing speed of a computer instruction is measured in terms of a billionth of a second. A unit of measurement for the speed of a computer is called Hertz (Hz). The second capacity of the computer is stored. Computers can store and retrieve data using a measure of memory called a byte.
What is a byte?
A byte is a combination of 8 bits, but a bit is either 0 or 1. In computer memory, each character typed is stored using a single byte.
A bit is a binary number equal to 0 or 1. Other measurement storage units include kilobytes (KB), megabytes (MB), gigabytes (GB), terabytes (TB), petabytes (PB), Exabytes (EB), Zettabyte (ZB), Yottabyte (YB), etc.
The last characteristic is precision. The computer can perform thousands of complicated mathematical operations per second(s) without human intervention. They are more reliable and accurate than humans and rarely make mistakes. The last characteristic that sets a computer apart from other machines is its ability to store and follow a set of instructions without human intervention. However, the accuracy of the computer depends on the algorithms developed and the programs stored. The algorithm is a step-by-step procedure to accomplish or solve a specific task or problem. When an algorithm is written in a computer language, it is called a program. A program is also defined as a set of instructions written in a computer language. The program tells the computer what to do with the data. When the computer is improperly programmed, users will encounter Garbage in Garbage out (GIGO). The greatest strength of today's computers is that computers get the job done more accurately and much faster.