Computer Science Unplugged
Computer Science Unplugged
The first thing to consider when buying a new computer is whether you want a desktop, a laptop or a tablet. The Kittridge Street Elementary School, in Los Angeles, killed its music program last year to hire a technology coordinator; in Mansfield, Massachusetts, administrators dropped proposed teaching positions in art, music, and physical education, and then spent $333,000 on computers; in one Virginia school the art room was turned into a computer laboratory.If history really is repeating itself, the schools are in serious trouble. Another advantage is that analog computers can frequently represent and solve a problem in real time”; that is, the computation proceeds at the same rate as the system being modeled by it. Their main disadvantages are that analog representations are limited in precision—typically a few decimal places but fewer in complex mechanisms—and general-purpose devices are expensive and not easily programmed.CS Unplugged is a collection of free learning activities that teach Computer Science through engaging games and puzzles that use cards, string, crayons and lots of running around. Some computers are designed to distribute their work across several CPUs in a multiprocessing configuration, a technique once employed only in large and powerful machines such as supercomputers , mainframe computers and servers Multiprocessor and multi-core (multiple CPUs on a single integrated circuit) personal and laptop computers are now widely available, and are being increasingly used in lower-end markets as a result.JCMST is a highly respected scholarly journal which offers an in-depth forum for the interchange of information in the fields of science, mathematics, and computer science. The ability to store and execute lists of instructions called programs makes computers extremely versatile, distinguishing them from calculators The Church-Turing thesis is a mathematical statement of this versatility: any computer with a minimum capability (being Turing-complete) is, in principle, capable of performing the same tasks that any other computer can perform.SNIP measures contextual citation impact by weighting citations based on the total number of citations in a subject field. The Apple I computer differed from the other hobby computers of the time at the beckoning of Paul Terrell owner of the Byte Shop who gave Steve Jobs his first purchase order for 50 Apple I computers only if the computers were assembled and tested and not a kit computer so he would have computers to sell to everyone, not just people that could assemble a computer kit.
Instead of simply copying the basic input output system (BIOS) of the Apple II as Franklin Computer had done, they reversed engineered the system and sold it for US $479, a much lower price than the comparable Apple II. While Apple sued to remove the Laser 128 from the market, they were unsuccessful and the Laser remained one of the very few Apple clones” for sale.All computers contain a central processing unit that interprets and executes instructions; input devices, such as a keyboard and a mouse, through which data and commands enter the computer; memory that enables the computer to store programs and data; and output devices, such as printers and display screens, that show the results after the computer has processed data.In keeping with these views New Jersey cut state aid to a number of school districts this past year and then spent $10 million on classroom computers. During recent visits to some San Francisco-area schools I could see what it takes for students to use computers properly, and why most don`t. Second, they believe that the human and physical world holds greater learning potential.Computers suffer frequent breakdowns; when they do work, their seductive images often distract students from the lessons at hand — which many teachers say makes it difficult to build meaningful rapport with their students. After all, the private sector, with its constant supply of used computers and the computer industry`s vigorous competition for new customers, seems well equipped to handle the situation. These notions are considerably less glamorous than computers are, but their worth is firmly proved through a long history. Unplugged has been used around the world for over twenty years, in classrooms, science centers, homes, and even for holiday events in a park!Perhaps counterintuitively, when kids take a break from a classroom lesson on the solar system to spend a quiet moment alone watching a three-minute nature video, or participate in a teacher-guided breathing exercise with their class after lunch, they seem to become better overall students. Parts of it specify the operation to be done, and parts specify the data on which it is to operate.
The activities introduce students to Computational Thinking through concepts such as binary numbers , algorithms and data compression , separated from the distractions and technical details of having to use computers. Because so much common knowledge and contextual information is assumed in ordinary human communication, researchers have yet to solve the problem of providing relevant information to general-purpose natural language programs. Analog computers use continuous physical magnitudes to represent quantitative information. Because of their current roles, these computers are now called servers rather than mainframes.Such systems remain important today, though they are no longer the sole, or even primary, central computing resource of an organization, which will typically have hundreds or thousands of personal computers (PCs). Mainframes now provide high-capacity data storage for Internet servers, or, through time-sharing techniques, they allow hundreds or thousands of users to run programs simultaneously. Minicomputers generally had limited computational power, but they had excellent compatibility with various laboratory and industrial devices for collecting and inputting data. In the 1980s it was common to distinguish between microprocessor-based scientific workstations and personal computers.The boundaries shift, however, and CPU chips now also contain some high-speed cache memory where data and instructions are temporarily stored for fast access. Since the early 1980s, CPU design has followed a style originally called reduced-instruction-set computing ( RISC ). This design minimizes the transfer of data between memory and CPU (all ALU operations are done only on data in CPU registers) and calls for simple instructions that can execute very quickly. In addition to main memory, computers generally have special video memory (VRAM) to hold graphical images, called bitmaps , for the computer display.The earliest forms of computer main memory were mercury delay lines, which were tubes of mercury that stored data as ultrasonic waves, and cathode-ray tubes, which stored data as charges on the tubes` screens. This memory is often dual-ported—a new image can be stored in it at the same time that its current data is being read and displayed. Nonetheless, data transfer through the bus”—the set of wires that connect the CPU to memory and peripheral devices—is a bottleneck. A well-designed cache allows up to 85-90 percent of memory references to be done from it in typical programs, giving a several-fold speedup in data access.This vast decline in cost made possible graphical user interfaces (GUIs), the display fonts that word processors use, and the manipulation and visualization of large masses of data by scientific computers. Secondary memory on a computer is storage for data and programs not in use at the moment. In addition to punched cards and paper tape, early computers also used magnetic tape for secondary storage. Computer display devices have been in use almost as long as computers themselves.