How Your PC Works Part
5:
How Computer
Memory Works
Computer memory is responsible
for a wide variety of tasks in the modern computer system.
Have you ever wondered how
that memory works? Computer memory is a difficult topic to understand -
but it is one of the most important computer concepts.
Your computer gets all sorts of
things done for you. If you're a complex
application, or playing the hottest 3D game, you can bet that the computer's
memory is responsible in some part for making it all work.
1. How Memory is Organized
Let's get started by seeing how computer memory is organized.
Think of memory in a PC as many 'boxes' to store numbers. Each box has a unique address.
Collections of these boxes work together to store meaningful instructions that
can be interpreted by programs.
The numbers stored in individual bytes in memory range from 0 to
255. For those more technically inclined, this is really what can be represented
by 8 bits. Each 'box' stores 1 byte and 1 byte = 8 bits.
2. Parameters Defining A Memory Module
Ok, now that you know how memory is organized, let's understand what defines a
particular memory module. The key parameters defining a
given memory module in a PC are:
Capacity - Each memory module is designed to hold a
specific number of bytes.
The capacity of a
memory module is the number of bytes it can store.
Width - This one is a bit technical. Memory modules are
also assigned a width - which determines the number of bits the memory can
access at one time.
Access time - It takes time for the memory
to read its 'number' and get it ready for the CPU to use. This is known as the
access time. But do remember that a faster access time doesn't mean your PC will
run faster. The speed is still controlled very much by the speed of your CPU.
Cycle time - The cycle time defines the minimum time from
one memory operation to the next. If you add the access time to the time the
module needs to recover and start the next operation, you will get the cycle
time of the memory module.
Now, the bandwidth of the memory - the amount of data it can read and write per second
- depends on its width, access time, and cycle time. Clearly, higher width and faster
access and cycle times result in greater memory bandwidth.
Conclusion
Hopefully, this article has helped you understand
how computer memory works. Frankly, computer memory is a complex topic. If you
really want to understand the details, be sure to pick up a good book on the
topic. Happy computing!
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