Tuesday, June 5, 2007
Sunday, June 3, 2007
A device that receives, processes, and presents information. The two basic types of computers are analog and digital. Although generally not regarded as such, the most prevalent computer is the simple mechanical analog computer, in which gears, levers, ratchets, and pawls perform mathematical operations—for example, the speedometer and the watt-hour meter (used to measure accumulated electrical usage). The general public has become much more aware of the digital computer with the rapid proliferation of the hand-held calculator and a large variety of intelligent devices and especially with exposure to the Internet and the World Wide Web. See also Calculators; Internet; World Wide Web.
An analog computer uses inputs that are proportional to the instantaneous value of variable quantities, combines these inputs in a predetermined way, and produces outputs that are a continuously varying function of the inputs and the processing. These outputs are then displayed or connected to another device to cause action, as in the case of a speed governor or other control device. Small electronic analog computers are frequently used as components in control systems. If the analog computer is built solely for one purpose, it is termed a special-purpose electronic analog computer. In any analog computer the key concepts involve special versus general-purpose computer designs, and the technology utilized to construct the computer itself, mechanical or electronic. See also Analog computer.
In contrast, a digital computer uses symbolic representations of its variables. The arithmetic unit is constructed to follow the rules of one (or more) number systems. Further, the digital computer uses individual discrete states to represent the digits of the number system chosen. A digital computer can easily store and manipulate numbers, letters, images, sounds, or graphical information represented by a symbolic code. Through the use of the stored program, the digital computer achieves a degree of flexibility unequaled by any other computing or data-processing device.
The advent of the relatively inexpensive and readily available personal computer, and the combination of the computer and communications, such as by the use of networks, have dramatically expanded computer applications. The most common application now is probably text and word processing, followed by electronic mail. See also Electronic mail; Local-area networks; Microcomputer; Word processing.
Computers have begun to meet the barrier imposed by the speed of light in achieving higher speeds. This has led to research and development in the areas of parallel computers (in order to accomplish more in parallel rather than by serial computation) and distributed computers (taking advantage of network connections to spread the work around, thus achieving more parallelism). Continuing demand for more processing power has led to significant changes in computer hardware and software architectures, both to increase the speed of basic operations and to reduce the overall processing time. See also Computer systems architecture; Concurrent processing; Distributed systems (computers); Multiprocessing; Supercomputer.
A PC is a general purpose tool built around a microprocessor. It has lots of different parts -- memory, a hard disk, a modem, etc. -- that work together. "General purpose" means that you can do many different things with a PC. You can use it to type documents, send e-mail, browse the Internet and play games. In this article, we will talk about PCs in the general sense and all the different parts that go into them. You will learn about the various components and how they work together in a basic operating session. You'll also find out what the future may hold for these machines.
Let's take a look at the main components of a
typical desktop computer.
- Central processing unit (CPU) - The microprocessor "brain" of the computer system is called the central processing unit. Everything that a computer does is overseen by the CPU.
- Memory - This is very fast storage used to hold data. It has to be fast because it connects directly to the microprocessor. There are several specific types of memory in a computer:
- Random-access memory (RAM) - Used to temporarily store information that the computer is currently working with
- Read-only memory (ROM) - A permanent type of memory storage used by the computer for important data that does not change
- Basic input/output system (BIOS) - A type of ROM that is used by the computer to establish basic communication when the computer is first turned on
- Caching - The storing of frequently used data in extremely fast RAM that connects directly to the CPU
- Virtual memory - Space on a hard disk used to temporarily store data and swap it in and out of RAM as needed
Dell Computers
There are tons of different types of computers available at outrageous deals at the Dell Home and Home Office, Small Business and Canada online store. They have notebook and laptop computers (laptops include Inspiron and Latitude), desktop computers (desktops include Dimension, Media Center PCs, Optiplex and Precision Workstations) and servers (server systems include PowerEdge and PowerVault.) But the savings are not exclusively for a Dell computer, we also have deals for software and peripherals such as PDAs, printers, monitors, software, digital cameras, Plasma TV televisions, LCD TVs, juke boxes, handhelds and more.
Stackable Coupons
Sometimes there are stackable dell coupons. This means you can use the discount offer on top of other discounts you already have. The savings can really add up. However, sometimes the best discount deals aren't combinable with other offers. That's OK, because most offers by themself can provide tremendous savings.
Dell Coupon Code
If there is a Dell coupon code with an offer, you will need to enter it on the Dell.com web site in order to get the discount. Once you add an item and view your shopping cart, there is a place to "Enter a coupon number". Enter the coupon code in that box and click the apply button.
More Dell Deals
We generally list all deals from all sources for the various dell online stores. If you see a tv deal, we will likely list the same offer as you saw on tv. If you're looking for outlet store savings on computers, we have computor deals for you. Save for dell4me, dell4me.com, computers.com and other online dell .com deals–we strive to list all available Dell coupons!
A programmable machine. The two principal characteristics of a computer are:
Modern computers are electronic and digital. The actual machinery -- wires, transistors, and circuits -- is called hardware; the instructions and data are called software.
All general-purpose computers require the following hardware components:
In addition to these components, many others make it possible for the basic components to work together efficiently. For example, every computer requires a bus that transmits data from one part of the computer to another.
Computers can be generally classified by size and power as follows, though there is considerable overlap: