Programmability-CPUs can be programmed either by the chip manufacturer, distributor, or the computer manufacturer. Today, DEC's 64-bit Alpha microprocessor is more than 550 times as powerful as the 4004, with speeds comparable to yesterday's mainframes. The first microprocessor, the Intel 4004 4-bit (1971), measured just 1/8" by 1/16" yet was as powerful as the first electronic computer 25 years earlier (1946), which weighted 30 tons, used 18,000 vacuum tubes, and required so much electricity that the lights of West Philadelphia are said to have dimmed each time it was turned on. The results are temporarily stored in memory cells and released in a timed sequence through the bus system to output devices such as CRT Screens, networks, or printers. It receives and decodes instructions from input devices like keyboards, disks, or cassettes, then sends them over a bus system consisting of microscopic etched conductive "wiring" to be processed by its arithmetic calculator and logic unit. It thinks for the computer and, like a traffic cop, coordinates its operations. Microprocessor-A microprocessor, also called a CPU, is a tiny, enormously powerful high speed electronic brain etched on a single silicon semiconductor chip which contains the basic logic, storage and arithmetic functions of a computer. By the turn of the century, when high volume chips are capable of executing more than a billion instructions per second, doors will open to brave new worlds we can only begin to imagine such as holographic videoconferencing and personal digital assistants that beep your cardiologist when your stock portfolio slides. Today, Pentium processors and clones are driving the PC into untapped, new frontiers of mass-market communications and interactive multimedia home computing. At the same time, microprocessors have transformed the ubiquitous PC from a stand-alone office workhorse doing word-processing and spreadsheets to a widely connected, information machine that can send faxes and e-mail, access on-line services, or provide a video link for meetings. Over the last decade, these advances in pricing and processing power have made the personal computer the largest consumer of microprocessors. Consequently, microprocessors have taken over functions that used to require warehouses of discrete components, whetting a seemingly limitless appetite for increasingly affordable, higher performing chips. As chips get smaller, more of them can be etched onto the same diameter silicon wafer by improved fabrication equipment that today handles multiple-layer eight-inch wafers as easily as it did two- and three-inch, single-layer wafers ten years ago. More compact circuitry makes microprocessors faster because electrons have less distance to travel. Due to techniques that squeeze roughly twice as many circuits onto silicon every 18 months or so by decreasing line widths, increasing wafer diameters, and adding layers, each new generation eventually comes to market at around the same price as the last, but with twice the power. The microprocessor owes its phenomenal success to a paradox created by the combination of technology and economics.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |