NEW INTERVIEW QUESTIONS.COM HARDWARE INTERVIEW QUESTIONS COMPUTER ARCHITECTURE AND DESIGN INTERVIEW QUESTIONS DETAILS

Add to My Questions | Forward | Print

Question

What is a cache?

Answer

It turns out that caching is an important computer-science process that appears on every computer in a variety of forms. There are memory caches, hardware and software disk caches, page caches and more. Virtual memory is even a form of caching. Caching is a technology based on the memory subsystem of your computer. The main purpose of a cache is to accelerate your computer while keeping the price of the computer low. Caching allows you to do your computer tasks more rapidly. Cache technology is the use of a faster but smaller memory type to accelerate a slower but larger memory type. A cache has some maximum size that is much smaller than the larger storage area. It is possible to have multiple layers of cache. A computer is a machine in which we measure time in very small increments. When the microprocessor accesses the main memory (RAM), it does it in about 60 nanoseconds (60 billionths of a second). That's pretty fast, but it is much slower than the typical microprocessor. Microprocessors can have cycle times as short as 2 nanoseconds, so to a microprocessor 60 nanoseconds seems like an eternity. A computer is a machine in which we measure time in very small increments. When the microprocessor accesses the main memory (RAM), it does it in about 60 nanoseconds (60 billionths of a second). That's pretty fast, but it is much slower than the typical microprocessor. Microprocessors can have cycle times as short as 2 nanoseconds, so to a microprocessor 60 nanoseconds seems like an eternity. What if we build a special memory bank in the motherboard, small but very fast (around 30 nanoseconds)? That's already two times faster than the main memory access. That's called a level 2 cache or an L2 cache. What if we build an even smaller but faster memory system directly into the microprocessor's chip? That way, this memory will be accessed at the speed of the microprocessor and not the speed of the memory bus. That's an L1 cache, which on a 233-megahertz (MHz) Pentium is 3.5 times faster than the L2 cache, which is two times faster than the access to main memory. Some microprocessors have two levels of cache built right into the chip. In this case, the motherboard cache -- the cache that exists between the microprocessor and main system memory -- becomes level 3, or L3 cache. Submitted by Gargee Deshmukh (gargee_vdeshmukh@yahoo.co.in) © NewInterviewQuestions.com

Answer:*
Name:*
Email Address:*
Verification Code	Not readable? Load New Code
Enter the above shown code:*

Category	Computer Architecture and Design Interview Questions
Rating	(3.0) By 1 users
Added	7/6/2005
Views	154650
Rate it!	* * * * * * * * * * * * * * *
Free Offers:	300 Free Magazines for you. No credit card required. No Shipping Charges. Absolutely Free for 1 Year.

Please Note: We keep on updating better answers to this site. Subscribe to our newsletter to get notified when better answer is posted.

Notify me when better answer is posted!
Email: