Computer Fundamentals and System Concepts

The earliest device that qualifies as a digital computer is Abacus

The history of computing hardware covers the developments from early simple devices to aid calculation to modern day computers. Before the 20th century, most calculations were done by humans. Early mechanical tools to help humans with digital calculations, such as the abacus, were called "calculating machines", called by proprietary names, or referred to as calculators. The machine operator was called the computer.

1,00,00,00,000 operations per second can perform by a modern fast mainframe digital computer.

Under ideal circumstances, a high-end desktop x86 processor can execute over 100 billion instructions per second. In real world usage scenarios, however, the CPU is often stuck waiting for other components to answer back, mostly RAM and disk.

Clock Speeds are usually determined in MHz, 1 MHz representing 1 million cycles per second, or in GHz, 1 GHz representing 1 thousand million cycles per second. The higher the CPU speed, the better a computer will perform, in a general sense.

In analog computer Input is never converted to digital form.

An analog computer or analogue computer is a type of computer that uses the continuously changeable aspects of physical phenomena such as electrical, mechanical, or hydraulic quantities to model the problem being solved. ... Analog computers can have a very wide range of complexity.

An analog computers, works by measuring voltages and currents rather than by the process of counting. An analog computers works on supply of continuous electrical signals and display outputs continuously. Side rule is an example analog device in which numbered as expressed as distances.

After being denied Cray supercomputers, India started a program to develop indigenous supercomputers and supercomputing technologies.

The first super Computer in India was Param 8000 . It was an Initiative program of Center for Development of Advanced Computing(C-DAC) in India which was started in 1980’s.

In 1991 Param 8000 became the first super computer of India.

Smaller and less expensive PC-based servers are replacing Mainframe in many businesses.

Mainframe computers (colloquially referred to as "big iron"[1]) are computers used primarily by large organizations for critical applications; bulk data processing, such as census, industry and consumer statistics, enterprise resource planning; and transaction processing. They are larger and have more processing power than some other classes of computers: minicomputers, servers, workstations, and personal computers.

Modern mainframes can run multiple different instances of operating systems at the same time. This technique of virtual machines allows applications to run as if they were on physically distinct computers. In this role, a single mainframe can replace higher-functioning hardware services available to conventional servers. While mainframes pioneered this capability, virtualization is now available on most families of computer systems, though not always to the same degree or level of sophistication.

Mainframes are designed to handle very high volume input and output (I/O) and emphasize throughput computing.

Supercomputers are specially designed computers that perform complex calculations extremely rapidly.

A supercomputer is a computer with a high level of performance compared to a general-purpose computer. Performance of a supercomputer is measured in floating-point operations per second (FLOPS) instead of million instructions per second (MIPS). As of 2017, there are supercomputers which can perform up to nearly a hundred quadrillion FLOPS. As of November 2017, all of the world's fastest 500 supercomputers run Linux-based operating systems. Additional research is being conducted in China, the United States, the European Union, Taiwan and Japan to build even faster, more powerful and more technologically superior exascale supercomputers.

The IBM Blue Gene supercomputer uses the CNK operating system on the compute nodes, but uses a modified Linux-based kernel called I/O Node Kernel (INK) on the I/O nodes. CNK is a lightweight kernel that runs on each node and supports a single application running for a single user on that node.

A network operating system (NOS) is a computer operating system that is designed for network use. ... In particular, UNIX was designed from the beginning to support networking, and all of its descendants (i.e., Unix-like operating systems) including Linux and Mac OSX, feature built-in networking support.

IBM 7000 digital computer Has modular construction.

The IBM 7000 series is a series of large-scale (mainframe) computer systems that were made by IBM through the 1950s and early 1960s. The series includes several different, incompatible processor architectures. The 700s use vacuum tube logic and were made obsolete by the introduction of the transistorized 7000s. The 7000s, in turn, were eventually replaced by System/360, which was announced in 1964. However the 360/65, the first 360 powerful enough to replace 7000s, did not become available until November 1965. Early problems with OS/360 and the high cost of converting software kept many 7000s in service for years afterward.

Modular design, or "modularity in design", is a design approach that subdivides a system into smaller parts called modules or skids, that can be independently created and then used in different systems. A modular system can be characterized by functional partitioning into discrete scalable, reusable modules; rigorous use of well-defined modular interfaces; and making use of industry standards for interfaces.

Mainframe computers are specifically designed to support hundreds or thousands of users concurrently for large-scale transaction processing. While supercomputers are faster, they are typically optimized for complex calculations rather than multi-user support.

Unit of speed used for super computer is GELOPS. GELOPS comes from word gel/ops.

Quantum Computer is the smallest and fastest computer imitating brain working.

Quantum computing is computing using quantum-mechanical phenomena, such as superposition and entanglement. A quantum computer is a device that performs quantum computing. Such a computer is different from binary digital electronic computers based on transistors. Whereas common digital computing requires that the data be encoded into binary digits (bits), each of which is always in one of two definite states (0 or 1), quantum computation uses quantum bits or qubits, which can be in superpositions of states. A quantum Turing machine is a theoretical model of such a computer, and is also known as the universal quantum computer. The field of quantum computing was initiated by the work of Paul Benioff and Yuri Manin in 1980, Richard Feynman in 1982, and David Deutsch in 1985.

Arithmetic and logic unit is responsible for performing all the arithmetic computations such as addition, subtraction, division, multiplication and exponentiation. In addition to this it also performs logical operations involving comparisons among variables and data items.

General controls relate to the environment (access to programs), application controls relate to specific processing (exception reports), and user controls involve manual verification of results.

Utility programs are specialized software designed to perform maintenance and supporting operations for the computer system.

Application software consists of programs developed to help the user perform specific tasks, such as word processing or accounting.

System software, such as the operating system, is responsible for controlling the internal functions and hardware of the computer.