All spectrum of modern computing systems can be divided(shared) into three big classes: the mini computer (including personal computers), mainframes, Supercomputers. Now these classes it is not so much on appearance, how many on functionalities.
Modern personal computers have practically the same characteristics, as the mini computer of the eightieth years: 32-and 64-digit architecture and øèííóþ the organization of system. Now the class of the mini computer is extremely various: from íîóòáóêîâ and ïàëìòîïîâ (see. Classification of portable computers) up to powerful servers for systems of scale of the enterprise. Genetic attributes of this class of machines is the organization of system at which all devices "are strung" on the general(common) highway, and standardization of equipment rooms and software. Consumers focused on the broad audience minicomputer systems are unconditional leaders of sales in computer branch.
Inside a class of the mini computer it is accepted to allocate minicomputers and microcomputers. The term "minicomputers" was assigned by the senior models of servers using architecture RISC and UNIX. The basic manufacturers in the market of minicomputers are firms AT*T, Intel, Hewlett-Packard, DEC, Pyramid.
To microcomputers carry numerous models of personal computers, including not compatible with IBM PC, and also
Mainframes — universal general purpose computers. With blossoming minicomputer systems mainframes have lost the positions. However company IBM, the basic world manufacturer of mainframes, has managed to carry out a quantum leap — transition to new conceptual architecture ESA/390 which offers a wide spectrum of the functionalities, allowing to use mainframes as the center of integration of the non-uniform computer complex. Cost of mainframes is rather high — one computer with a package of applied programs is estimated approximately in one million dollars. { IBM}
Mainframes are actively used in financial sphere, a defensive complex and borrow(occupy) from 20 up to 30 % of the computer market. The greatest quantity(amount) makes IBM. Considerably smaller sales volumes at firms Unisys and Amdahl.
Supercomputers are necessary for work with the appendices demanding of productivity at least in hundred billions of operations with the floating point in second. They are applied to complex(difficult) calculations in aerodynamics, meteorology, physics high Supercomputers have found and in financial sphere. They are distinguished with high cost — from fifteen millions dollars, therefore the decision on their purchase quite often is accepted at the state level, the system of trade is advanced by second-hand supercomputers. The basic manufacturer of such computers — firm Cray Research based
