Understanding Computer Memory

Written by Stephen Bucaro


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Understanding Computer Memory

By Stephen Bucaro

Understanding computer memory is important because your computer's memory is whererepparttar 107803 action is. Sure your computer's central processing unit (CPU) may berepparttar 107804 computer's brain, but what good is a brain without memory?

Because memory is such an important part ofrepparttar 107805 computer, it has been redesigned and tweaked overrepparttar 107806 years to make it store more data and work faster. That has resulted in all kinds of technical terms and contractions. In this article, I attempt to clear up some of these terms and give you a basic understanding of computer memory.

When you work with an application on your computer, it is loaded into "main memory". There are other kinds of memory besides main memory. For example, there is "flash BIOS" memory and "cache" memory. In fact, I could argue that a computer consists mainly of memory. Evenrepparttar 107807 CPU consists mainly of a type of memory called "registers". In this article, I focus on main memory.

Memory is actually an array of "cells". Each cell holds a binary bit, either 0 or 1. The cells are arranged in rows of 32 cells to store each "word". A word might containrepparttar 107808 bits to code a single number or a single character. Each word can be accessed by it's address. A computer does not have to accessrepparttar 107809 addresses in numerical order. It can store or retrieve a word from any address at random, hencerepparttar 107810 term "random access memory" (RAM).

Because a computer needs millions of memory cells, they have to be cheap. The cheapest memory cell is an extremely tiny capacitor. In reality "0" means no electric charge is stored inrepparttar 107811 cell and "1" means an electric charge is stored inrepparttar 107812 cell.

A tiny capacitor can store an electric charge, but that charge dissipates off within a few milliseconds. To prevent loss ofrepparttar 107813 data,repparttar 107814 computer uses circuitry that repeatedly scans allrepparttar 107815 memory cells and refreshesrepparttar 107816 charge in any cells that contain a "1". This circuitry operates between accesses ofrepparttar 107817 memory byrepparttar 107818 CPU and other components. This continuous recharging is referred to as "dynamic" refresh, hencerepparttar 107819 term "dynamic" RAM (DRAM).

I am always surprised at how many people who work with computers don't understand what a "bus" is. It's very simple. You need a wire to connect to a memory cell. Instead of a wire, a circuit board uses a copper "trace" inside or onrepparttar 107820 surface ofrepparttar 107821 circuit board. To access a word of data, you need 32 parallel traces. You also need a few traces to carryrepparttar 107822 signals that control whether you are reading or writingrepparttar 107823 memory. This describesrepparttar 107824 "data bus".

To access a word of data, you need to providerepparttar 107825 address ofrepparttar 107826 word. It requires 64 parallel traces forrepparttar 107827 "address bus". There are many other parallel groups of traces onrepparttar 107828 circuit board that conduct various communication and control signals, each of them is referred to as a "bus". The most important signal tracing aroundrepparttar 107829 circuit board isrepparttar 107830 system clock.

File Compression

Written by Varuna Sood


Large files can be stored either in their original format or in a compressed format to save space .Different types of file compression are used for different types of files, such as text, graphics, and audio. You usually can reduce a large file by at least 50%, depending onrepparttar type of file andrepparttar 107800 type of compression. In case of audio files, for example,repparttar 107801 MP3(Mpeg audio layer3) format can be used to reduce audio files by as much as 90% to 93%. Bigger is never better when you are trying to move a large file acrossrepparttar 107802 Net. Other ways to fill a 13 Gb hard drive include

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