IBM Mainframe Computer Reaches 50 Years

On April 7, 1964 officially IBM announced the launch of System/360, which is natural considered to be the founder of modern mainframes, supercomputers for the execution of large amounts of data. The launch of System/360, the idea underlying the IBM mainframe modern, redesigned the industry and the market for computing – right 50 years ago. We talked about the Mainframe Computers and the evolution of the computing within the period of 1950-2010.

Though there were already classified mainframe machines before he launch of System/360, with this model IBM actually introduced the idea of creating the standards for the structure of hardware and software of computers. Before System/360 computer was designed starting from scratch with hardware and software specifically designed to work exclusively on this single device.

IBM Mainframe Computer Was a Successful Idea

Tom Watson of IBM immediately decided to cut off the production of all the others and focus only on the System/360.  The decision was well paid – between 1965 and 1971 the income of the company raised from 3.6 billion to 8.3 billion, and in the course in the 70s, almost 60% of the mainframe computers sold were of IBM.

Contrasting with at-the-time of industrial practice, IBM created an entire series of computers from small to large, low to high performance. The design made a clear distinction between architecture and implementation, allowing IBM to release a suite of compatible designs at different prices. All but the incompatible model 44 and the most expensive systems used microcode to implement the instruction set, which featured 8-bit byte addressing and binary, decimal and floating-point calculations. IBM stopped marketing all System/360 models by the end of 1977. System/360 introduced a number of industry standards :

1. Byte-addressable memory
2. Standardized bus and I/O channel
3. Nine track magnetic tape
4. 64-bit Program status word (PSW)

Peripherals interfaced to the system via channels. A channel was a specialized processor with the instruction set optimized for transferring data between a peripheral and main memory. In modern terms, this could be compared to direct memory access (DMA).