Keeping things in your Memory
Recently I received an email from a co-worker mentioning that her laptop was running slow. She also mentioned that Windows told her that the virtual memory on her computer was getting low. Not sure what to do she sent an email asking me what might be the cause for the slowness.
First let’s define virtual memory. Virtual memory is hard drive space that windows uses as additional memory when running applications. Think of this as the swap file for Windows, a buffer area of the hard drive where items are written to while in use between saves to help memory be used more efficiently. Typically this happens when all or most of the memory on a PC is in use, Windows uses disk space to alleviate some of the load from physical memory.
Windows passes items in memory to the virtual memory area of the hard disk before it writes them to the drive for storage. When you save a document, these changes are written to disk. Virtual memory allows physical memory to operate more efficiently by allocating a set portion of disk space for use as a buffer area, allowing items to be stored there and less write operations to take place, thereby increasing performance.
Windows mentioned in an error or alert message box that the Virtual memory was full. More frequent saving should remedy this issue. Usually Windows tries to manage this disk space and will resize and allocate additional space as needed. Clearing this buffer is as simple as restarting your PC, just like things in memory, things in virtual memory are also dumped when a restart occurs.
I know several Windows users who see the amount of memory (Ram) and the amount of Hard disk Space as the same thing. Surely this has to do with the fact that they are both measured in Megabytes and Gigabytes of storage space. While they are similar in function, they are different. I will try to explain how below:
Your computer has a hard drive in it which may have a size from 20 to 100 Gigabytes (GB). About.com has a conversion table, which i placed below, to present file size differences and conversions.
Exact Conversion
1,024 Byte = 1 Kilobyte (KB)
1,024 Kilobyte (KB) = 1 Megabyte (MB)
1,073,741,824 Bytes = 1 Gigabyte (GB)
1 Gigabyte (GB) = 1,024 Megabyte (MB)
This means that a computer with a 20Gb hard disk can store 20 * 1,024 mega bytes of data. When you save files on your PC, they use up the available hard disk space. Windows typically requires 2 – 5 GB of storage for the operating system itself, which allows files needed to operate windows to be kept on your PC.
The items stored on your hard drive are written to the disk so that you can turn off your PC or restart your PC and not lose the data written there.
A note about upkeep: Windows stores things in the best manner it can when it writes to the hard disk, however these allocation tables and databases kept by windows to keep files in the best possible order can become fragmented and decrease performance. When windows writes to disk it writes sections of the file to available space on disk and tries to minimize the need to look elsewhere on the disk for parts of a file, the more times the computer has to read the disk to find pieces of a file, the more fragmented the disk becomes. To combat this and improve performance, running a defragmentation is recommended at least once per month. I will look at defragmenting a hard drive in another article.
If your PC had to get things from the hard disk every time it needed something, performance would suffer quite alot. So computers use Random Access Memory (RAM) to store files on your computer that are in use. Think of this as working storage for files and operating system components that are open.
The web browser you are reading this in is loaded into memory when you double click the icon to launch it and lives there until it is closed by the user (or it crashes for some reason). Other applications, like excel sheets and word documents are also stored there while in use. This allows Windows to spend less time reading from the hard disk while you are working on a document, improving performance.
Memory is volatile.
