Memory
What is memory ?
People in the computer industry commonly use the term "memory" to refer to RAM (Random Access Memory). As your processor cranks on your game, it uses RAM to store some of the data needed to make your game work. While all forms of memory work together, RAM is considered the main memory since most data, regardless of its source, is stored in RAM before it is registered in any other storage device. Consequently, RAM is used millions of times every second. A computer uses Ram to hold temporary instructions and data needed to complete tasks. This enables the computer's CPU (Central Processing Unit), to access instructions and data stored in memory very quickly.
Memory. At the word we think of human memory, and of machine memory(i.e)Computer memory.
Memory is a vital part of both machine and animal. Without it we as humans would not have any consciousness and the ability to create. Animals would not be able to survive.
In machines, and especially in computers, memory allows the machine to function in various ways, for example software to be run and data to be saved and processed.
Memory. Something just about everyone could use more of, including your computer. Memory is the ability to retain data for a period of time, short or long. This data can be of a complexity including imagery, sounds, sensations, smells and other sensations like human memory, or it can be predetermined data as in computer memory.
One of the differences between human and machine memory is that we can program and access machine memory through the use of software, but we cannot access human memory in the same straightforward manner.
Lets now talk about computer memory.
To start with there are basically two types of memory for a computer: storage space (hard drive) and active memory (RAM).
We will focus on active memory or RAM.
Computer Memory - RAMPeople in the computer industry commonly use the term "memory" to refer to RAM (Random Access Memory). As your processor cranks on your game, it uses RAM to store some of the data needed to make your game work. While all forms of memory work together, RAM is considered the main memory since most data, regardless of its source, is stored in RAM before it is registered in any other storage device. Consequently, RAM is used millions of times every second. A computer uses Ram to hold temporary instructions and data needed to complete tasks. This enables the computer's CPU (Central Processing Unit), to access instructions and data stored in memory very quickly. Computer memory is extremely important to computer operation. Files and programs are loaded into memory from external media like fixed disks (hard drives) and removable disks (floppies tapes). Memory can be built right into a system board, but it is more typically attached to the system board in the form of a chip or module. Inside these chips are microscopic digital switches which are used to represent binary data.
A good example of this is when the CPU loads an application program - such as a word processing or page layout program - into memory, thereby allowing the application program to work as quickly and efficiently as possible. In practical terms, having the program loaded into memory means that you can get work done more quickly with less time spent waiting for the computer to perform tasks.  |
The process begins when you enter a command from your keyboard. The CPU interprets the command and instructs the hard drive to load the command or program into memory. Once the data is loaded into memory, the CPU is able to access it much more quickly than if it had to retrieve it from the hard drive.
This process of putting things the CPU needs in a place where it can get at them more quickly is similar to placing various electronic files and documents you're using on the computer into a single file folder or directory. By doing so, you keep all the files you need handy and avoid searching in several places every time you need them.
In general the more RAM a computer has the faster the computer operates. Why? RAM is where all the information is kept just before the computer needs to use it.
Think of it this way. During a conversation a person can speak without interruption if everything being talked about is in his or her memory. However, if a person does not have enough memory and has to look something up during the course of the conversation, in a book or newspaper, then the conversation stops until the needed information is found.
Computers are very similar; they can continue processing without interruption as long as all needed information is in memory (RAM). When that is not the case, the computer stops, retrieves the needed information from storage (i.e. Hard drive, CD, disk) and places it into memory and then continues processing. The more interruptions the computer receives to retrieve information the slower the computer. The more memory a computer has, the fewer interruptions and the faster the computer operates. More memory equates to more speed.
These days, no matter how much memory your computer has, it never seems to be quite enough. Not long ago, it was unheard of for a PC (Personal Computer), to have more than 1 or 2 MB (Megabytes) of memory. Today, most systems require 64MB to run basic applications. And up to 256MB or more is needed for optimal performance when using graphical and multimedia programs.
As an indication of how much things have changed over the past two decades, consider this: in 1981, referring to computer memory, Bill Gates said, "640K (roughly 1/2 of a megabyte) ought to be enough for anybody."
For some, the memory equation is simple: more is good; less is bad. However, for those who want to know more, this reference guide contains answers to the most common questions, plus much, much more.
note:A computer's system RAM alone is not fast enough to match the speed of the CPU. That is why you need a cache memory.
Different Types Of RAM'S
This refresh operation is where dynamic RAM gets its name. Dynamic RAM has to be dynamically refreshed all of the time or it forgets what it is holding. The downside of all of this refreshing is that it takes time and slows down the memory.
2)Static RAM:Static RAM uses a completely different technology. In static RAM, a form of flip-flop holds each bit of memory . A flip-flop for a memory cell takes 4 or 6 transistors along with some wiring, but never has to be refreshed. This makes static RAM significantly faster than dynamic RAM. However, because it has more parts, a static memory cell takes a lot more space on a chip than a dynamic memory cell. Therefore you get less memory per chip, and that makes static RAM a lot more expensive.
note:static RAM is fast and expensive, and dynamic RAM is less expensive and slower. Therefore static RAM is used to create the CPU's speed-sensitive cache, while dynamic RAM forms the larger system RAM space.
note:A computer's system RAM alone is not fast enough to match the speed of the CPU. That is why you need a cache memory.
Different Types Of RAM'S
1)Dynamic RAM:Dynamic RAM is the most common type of memory in use today. Inside a dynamic RAM chip, each memory cell holds one bit of information and is made up of two parts: a transistor and a capacitor. These are, of course, extremely small transistors and capacitors so that millions of them can fit on a single memory chip. The capacitor holds the bit of information -- a 0 or a 1 (see How Bits and Bytes Work for information on bits). The transistor acts as a switch that lets the control circuitry on the memory chip read the capacitor or change its state.
A capacitor is like a small bucket that is able to store electrons. To store a 1 in the memory cell, the bucket is filled with electrons. To store a 0, it is emptied. The problem with the capacitor's bucket is that it has a leak. In a matter of a few milliseconds a full bucket becomes empty. Therefore, for dynamic memory to work, either the CPU or the memory controller has to come along and recharge all of the capacitors holding a 1 before they discharge. To do this, the memory controller reads the memory and then writes it right back. This refresh operation happens automatically thousands of times per second. This refresh operation is where dynamic RAM gets its name. Dynamic RAM has to be dynamically refreshed all of the time or it forgets what it is holding. The downside of all of this refreshing is that it takes time and slows down the memory.
2)Static RAM:Static RAM uses a completely different technology. In static RAM, a form of flip-flop holds each bit of memory . A flip-flop for a memory cell takes 4 or 6 transistors along with some wiring, but never has to be refreshed. This makes static RAM significantly faster than dynamic RAM. However, because it has more parts, a static memory cell takes a lot more space on a chip than a dynamic memory cell. Therefore you get less memory per chip, and that makes static RAM a lot more expensive.
note:static RAM is fast and expensive, and dynamic RAM is less expensive and slower. Therefore static RAM is used to create the CPU's speed-sensitive cache, while dynamic RAM forms the larger system RAM space.
