History of computing

   The next major step in the history of computer technology was the invention of the transistor in 1947. They have replaced fragile and energy-intensive lamps. On computers based on transistors commonly referred to as the "second generation", which dominated the 1950's and early 1960's. With transistors and circuit boards, there was a significant decrease in the size and volume of energy consumption and increased reliability. For example, IBM 1620-transistor, which has become the replacement IBM 650 for lamps, was the size of an office desk. However, the second generation computers were still quite expensive and therefore used only by universities, governments, large corporations.

   Computers of the second generation usually consisted of a large number of printed circuit boards, each containing one to four logic gates or flip-flops. In particular, IBM Standard Modular System defines a standard for such hardware and connectors to connect to them. In 1959, on the basis of transistors mainframe IBM released the IBM 7090 machine and mid-range IBM 1401. The latter used the card-entry and become the most popular general-purpose computers of the time: in the period 1960-1964 years. was issued more than 100 thousand copies of this machine. It used memory for 4000 characters (later increased to 16 000 characters). Many aspects of this project were based on a desire to replace the card-machines, which were widely used from 1920 until the beginning of 1970. In 1960 IBM released IBM transistor 1620, initially only perfolentochnuyu, but was soon updated to punch cards. The model has become popular as a scientific computer, was released around 2000 copies. The machine used magnetic core memory of up to 60 000 decimal digits.

   In the same 1960 DEC released its first model - PDP-1, intended for use by technical staff in laboratories and for research.

   In 1961, Burroughs Corporation released the B5000, the first dual-processor computer with virtual memory. Another unique feature was stack architecture, addressing on the basis of descriptors, and the lack of programming directly in assembly language.