Text b generations of computers

The subsequent development of computers is usually described as occurring in generations. The first generation, which began with Eckert and Mauchly's ENIAC, is considered to span the period 1946-1959. This generation of computers is characterized by the use of vacuum tubes in the CPU and internal memory units, the first commercial computers, and many fundamental advances in computing. The first commercial computer was the UNIVAC 1 (UNIVersal Automatic Computer), which was sold to the Census Bureau in 1951.

In the second generation of computers, 1959-1964, the vacuum tube was replaced by the transistor. The transistor, a solid-state device, was the major breakthrough that allowed computers to have reasonable size and power. A solid-state device is made of minerals so that it can be instructed to allow or not allow a flow of current. Because solid-state devices did not use the hot filament that was in vacuum tubes, the use of transistors reduced the computer's heat output and power requirement. Transistors also increased the reliability of the computer, because they did not burn out the way vacuum tubes did. This breakthrough in turn reduced the cost of owning and operating a computer. This period saw tremendous growth in the use of computers by government, business, and industry.

The introduction of the integrated circuit in 1965 was the beginning of the third generation of computers. With this technological advance, an entire circuit board containing transistors and connecting wires could be placed on a single chip. This development meant greater reliability and compactness combined with low cost and power requirements. During this period, IBM controlled the mainframe market with its 360 (later to be 370) series of computers. This series was so well designed and built that its successors are still in heavy use today.

The fourth and current generation of computers began in 1971 with the introduction of the microprocessor—a central processing unit on a chip. This generation includes the introduction of supercomputers. These "monster computers" are in heavy demand for military and meteorological applications that require a high speed of operation. Another important advance of this generation has been the introduction of the personal computer, because the power of the computer has been made available to anybody who wishes to use one.

A possible "fifth generation" of computers has recently been discussed in the media. The Japanese government has a broad-ranging plan to leapfrog American superiority in hardware with a fifth-generation computer that will include parallel processors—several CPUs working in parallel to speed up execution time. No one knows how successful this particular plan will be, but we probably won't have to wait long to find out.

Text c monitoring weather at portland general electric

At Portland General Electric (PGE), an electric power utility company in Portland, Oregon, monitoring the weather and smokestack emissions is not just a sidelight, it's a requirement of doing business. Because PGE operates a nuclear power plant, the Nuclear Regulatory Commission (NRC) requires that weather conditions, which might affect the dispersal of routine low levels of radiation released from the plant, be monitored daily. This includes measuring wind speeds and directions and other atmospheric conditions. Similarly, to meet air quality and stack emission requirements of the Oregon state environmental office, PGE must monitor the emissions from its coal plant and two combustion turbine plants.

While keeping accurate environmental records can be expensive, PGE's failure to do so could result in regulatory fines. In 1986, when a PC system was installed, PGE used a monitoring system that involved collecting magnetic tapes from weather and emissions data loggers, mounting the tape on PGE's mainframe, and executing a program to produce the needed reports. This system involved a lag of several days between the collection of data and the meteorologist's being able to check it for possible malfunctions in the data recording device. Thus, any malfunctions would not be discovered for several days. The data logger was backed up by strip charts, but significant additional labor was required to convert the data to a usable form.

To speed up the processing of weather data, in 1989 PGE installed a local area network (LAN) composed of PCs that accept the data from an improved data logger/cassette recorder system. These PCs are used to check the data for reasonableness using a series of BASIC programs written by meteorologist Terry Worrell. After being processed by PCs on the LAN, the data are transferred to PGE's mainframe, where more accuracy checks are run before the data are included in reports that are sent to the NRC. The data are also transferred to a PC-based data base management program that generates reports for the state environmental office