Question

what is cache memory ?

Answer 1

In a computer there are a few different types of memory. Main memory (disk) is very cheap (you can get a 1 TB drive now for under $100!) but it is expensive in terms of access time.

Cache memory, on the other hand, is expensive (it's on chip, so you can only have a limited amount) but because it's so close to the CPU, access times are very fast. So when a program is running on your computer, it tries to put important information in cache, for quick access.

See http://en.wikipedia.org/wiki/CPU_cache

Answer 2

Imagine you're taking a test, and you're allowed to bring two things to the test with you: a textbook, and a piece of paper on which you're allowed to do work. The textbook is large and filled with information, but to find the information you need during the test might take a while, since the book's index is not that great. The textbook is like a computer's main memory.

The piece of paper can barely fit any information at all, but it's great for jotting little notes for yourself while you're taking the test, or storing numbers as you're working on a problem. After the test, you're probably just going to throw that piece of paper away and start again with a fresh piece of paper for the next test. This piece of paper is like cache memory.

Answer 3

The cache memory is a very fast memory (usually a SRAM) situated between the main RAM (usually DRAM) and the CPU; in the cache memory the CPU can find the most important data for the current operation.

Answer 4

Many times data that is accessed often will be put into a memory cache in order for instant retrieval of the data. This can improve performance of the software many times over because your computer will already have the information in its memory. Another form of cached memory is a shared memory pool whereby a chunk of memory is reserved in order to load some data table that many people can use (as in a mainframe), like a zip code table or a state code table. So Cache can either refer to on-board hardware or it may refer to a chunk of data that is frequently accessed, like a cached web page for example. (I hope this helps)

Answer 5

shandelman and tread831 explained this very well. Cache is a RAM (Random Memory Access) type that is accessed before the regular cache. Therefore, if you, for example, have been to a website or opened that document recently, your computer doesn't need to search and fetch for the information. It simply looks in cache first and loads that, which is much faster than searching an index of your entire hard drive, or even go to the web and get the data. Occasionally I empty the cache and "start fresh" like tread831 mentions.

In addition, there is also PREFETCH that is not as known to the casual user. It is the information Windows Users have in the system that "Auto-Loads" recent and often used programs and other data each time your computer is turned booted up. I find it helpful to empty its contents occasionally as well. The PREFETCH folder can be located usually at "C:\Windows\Prefetch"

Answer 6

thanks to all.................