This is the 12th day of my participation in the August Text Challenge.More challenges in August

  1. Development of computer
  2. The hierarchy of computer systems
  3. Performance indicators of a computer

The knowledge structure

01 The history of the computer

Development of computer hardware

  • The first generation of computer: valve computer

The first generation of computers (from the mid-1940s to the late 1950s) were electron tube computers, whose logic elements were electronic tubes and whose memory devices were acoustic delay lines or magnetic drums. The word “software” did not yet exist, and the tools used for programming were low-level languages. Vacuum tube computers are large in size, slow in speed (thousand or ten thousand times per second), and small in memory capacity.

  • Second generation computer: transistor computer

The second generation of computers (from the mid-late 1950s to the mid-1960s) were transistorized computers (the transistor was invented by Bell Laboratories in the United States in 1947). This generation of computer in addition to the logic components using transistors, its memory using magnetic core memory, external memory using magnetic drum and tape memory, floating point operation, and put forward new concepts such as switching, interrupt, I/O processor. At this time, computer software appeared a variety of high-level languages and their compiler.

  • The third generation computer: integrated circuit computer

The third generation of computers (from the mid-1960s to the mid-late 1970s) is the integrated circuit computer (the integrated circuit was invented in 1958 so that the logic elements and memory of the computer can be realized by the integrated circuit). At this time, a series of new computer technologies appeared, including microprogram control, cache, virtual memory and pipeline technology. In terms of software, the operating system is realized first, with resource scheduling, man-machine communication and input and output control functions.

  • The fourth generation computer: vlSI computer

The fourth generation of computers (beginning in the late 1970s) are vlSI computers. Large scale (LSI) and very large scale (VLSI) integrated circuits become the main components of computers, and the integration degree is getting higher and higher, the emergence of microprocessor. Another important characteristic of the fourth generation computer period is the development and wide application of computer networks.

Moore’s law

Moore’s Law was developed by Gordon Moore, one of the founders of Intel. At constant prices, the number of components that can be accommodated on an integrated circuit doubles roughly every 18-24 months, and so does its performance. In other words, the amount of computer power a dollar buys will more than double every 18-24 months. This law reveals the speed of progress in information technology. Although this trend has been going on for more than half a century, Moore’s Law should still be considered observation or speculation, not a physical or natural law. The law is expected to continue until at least 2015 or 2020. However, the 2010 update to the international semiconductor technology Roadmap has slowed growth by the end of 2013, and transistor density is only expected to double every three years after that.

Development of computer software

The development of software is promoted and restricted by computer hardware and computer application, and its development process can be roughly divided into three stages.

  • The first stage (1946-1956) was from the appearance of the first machine code programs on the first computers to the appearance of practical high-level languages. In this period, machine language programming was used directly, and the word software had not yet appeared.
  • The second stage (1956-1968) is the period between the emergence of practical high-level programming languages and the emergence of software engineering concepts. In order to improve the efficiency of programming, advanced language appeared during this period. In order to make full use of processor, memory and input and output computer resources, the emergence of operating system; In order to adapt to a large number of data processing, the emergence of database and its management system.
  • Since the emergence of software engineering has been in the third stage. For some complex large-scale software, the traditional development mode based on individual and simple team division of labor is not only inefficient, poor reliability, and difficult to complete, so it must be realized by engineering method.

Classification and development of computer

  • Single instruction stream & Single data Stream (SISD) : the von Neumann architecture
  • Single instruction stream & Multiple Data Stream (SIMD) : array processor, vector processor
  • Multiple instruction streams & Single data streams (MISD) : virtually non-existent
  • Multi instruction stream & Multi data Stream (MIMD) : multi processor, multi computer