Cache By: Thanh Nguyen

What is cache? Cache is a high speed storage mechanism that speed up your data processing speed.

Cache - example A librarian without cache

Cache - example A librarian with some cache 5

Cache - example Even more cache.. 5

Terms Hit/ miss L1 L2

Idea Overall, the idea of cache technology is the use of a faster but smaller memory type to accelerate a slower but larger memory type

Normal caching system L1 cache – Memory accesses at full microprocessor speed (10 nanoseconds, 4 kilobytes to 16 kilobytes in size) L2 cache – Memory access of type SRAM (around 20 to 30 nanoseconds, 128 kilobytes to 512 kilobytes in size) Main memory – Memory access of type RAM (around 60 seconds, 32 megabytes to 128 megabytes in size) Hard disk – Mechanical, slow (around 12 milliseconds, 1 gigabyte to 10 gigabytes in size) Internet – Incredibly slow (between 1 second and 3 days, unlimited size)

Common question “If L1 is so fast, why not make all of the computer’s memory run at the same speed as L1 cache, so no caching would be required?”

Answer Yes, we could but the general idea is: Build something small but fast Build something large but slow Build something large but fast

Cache in everything.. Types of cache Browser cache Memory cache Disk cache Processor cache

Source http://goo.gl/JoOf14 Librarian image http://goo.gl/NKjcg3 Shopping cart image http://goo.gl/hIEUUY Backpack image http://computer.howstuffworks.com/cache.htm http://www.techterms.com/definition/cache