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Processing: CPUThe CPU, or Central Processing Unit, is the part of the computer where work gets done. Many computers today have more than one processing chip, resulting in more complex but faster processing. Main Memory stores the commands that the CPU executes and the results.
Explanation: Processing: Machine Cycle The computer can only do one thing at a time. Each action must be broken down into the most basic steps. One round of steps from getting an instruction back to getting the next instruction is called the Machine Cycle.
For example, to add the numbers 5 and 6 and show the answer on the screen requires the following steps:
Speed The immense speed of the computer enables it to do millions of such steps in a second. Processing: Memory Addresses We need a method of naming the places where Main Memory stores data.
Rather than a street name and house number, memory addresses are just numbers. A memory address holds 1 byte of data where
You might wonder why 1024 instead of 1000 bytes per kilobyte. That is because computers don't count by tens like people. Computers count by twos and powers of 2. 1024 is 2 x 2 x 2 x 2 x 2 x 2 x 2 x 2 x 2 x 2, that is 2 times itself ten times. It's a rather convenient size number (for computers!). Update: Things are changing faster than I can type! The explanation above is no longer entirely true (July 2000). Different scientific and technical areas are using the words differently. For data storage devices and telecommunications a megabyte is 1 000 000 bytes. For data transmission in LANs a megabyte is 1 048 576 bytes as described above. But for data storage on a floppy disk a megabyte is 1 024 000 bytes! A new set of words has been created to make it clear what size is really being used. See http://physics.nist.gov/cuu/Units/binary.html È We all are impatient and want our computer to work as fast as possible, and certainly faster than the guy's at the next desk! Many different factors determine how fast your computer gets things done. Processor speed is one factor. But what determines the processor's speed? Processor Speed affected by:
You want a nice match between the word size and the bus size and the clock. It wouldn't do any good to have a bus that can deliver data 128 bits at a time, if the CPU can only use 8 bits at a time and has a slow clock speed. A huge line of data would form, waiting to get off the bus! When computers gets clogged like that, bad things can happen to your data. It's like people waiting to get into the theater. After a while, some of them may leave!! Processing: Physical Components There are several physical components of a computer that are directly involved in processing. The processor chip itself, the memory devices, and the motherboard are the main ones.
Memory Devices:
Memory Speed RAM (Random Access Memory) is what the computer uses as Main Memory. Memory speed measures the time it takes to move data in or out of memory. It is measured differently for different kinds of memory chips:
The capacity of a memory chip is measured in megabytes or gigabytes. For example, 256 MB of RAM is required to run WindowsXP and 512MB is much better. For Windows 7 the requirements are 1 gigabyte (GB) RAM (32-bit) or 2 GB RAM (64-bit). Several such memory boards can be installed in the computer to increase the amount of RAM available. Motherboards have only so many slots for memory so there are limits. Some motherboards require that all slots be filled and that all slots contain the same size memory board. It can get frustrating as there are no warning labels about this! Date: 2015-01-11; view: 2009
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