Main » TERM » C »


Pronounced cash, a special high-speed storage mechanism. Cache can be either a reserved section of main memory or an independent high-speed storage device. Two types of caching are commonly used in personal computers: memory caching and disk caching.

Memory Caching

A memory cache, sometimes called a cache store or RAM cache, is a portion of memory made of high-speed static RAM (SRAM) instead of the slower and cheaper dynamic RAM (DRAM) used for main memory. Memory caching is effective because most programs access the same data or instructions over and over. By keeping as much of this information as possible in SRAM, the computer avoids accessing the slower DRAM.


L1 and L2 Caches

Some memory caches are built into the architecture of microprocessors. The Intel 80486 microprocessor, for example, contains an 8K memory cache, and the Pentium has a 16K cache. Such internal caches are often called Level 1 (L1) caches. Most modern PCs also come with external cache memory, called Level 2 (L2) caches. These caches sit between the CPU and the DRAM. Like L1 caches, L2 caches are composed of SRAM but they are much larger.

Disk Caching

Disk caching works under the same principle as memory caching, but instead of using high-speed SRAM, a disk cache uses conventional main memory. The most recently accessed data from the disk (as well as adjacent sectors) is stored in a memory buffer. When a program needs to access data from the disk, it first checks the disk cache to see if the data is there. Disk caching can dramatically improve the performance of applications, because accessing a byte of data in RAM can be thousands of times faster than accessing a byte on a hard disk.

Smart Caching

When data is found in the cache, it is called a cache hit, and the effectiveness of a cache is judged by its hit rate. Many cache systems use a technique known as smart caching, in which the system can recognize certain types of frequently used data. The strategies for determining which information should be kept in the cache constitute some of the more interesting problems in computer science.

Facts about Cloud Computing in 2017

The following facts and statistics capture the changing landscape of cloud computing and how service providers and customers are keeping up with... Read More »

Facts about Computer Science: Education and Jobs

The following computer science facts and statistics provide a quick introduction to the changing trends in education and related careers. Read More »

Texting & Chat Abbreviations

From A3 to ZZZ this guide lists 1,500 text message and online chat abbreviations to help you translate and understand today's texting lingo. Read More »

The Five Generations of Computers

Learn about each of the five generations of computers and major technology developments that have led to the computing devices that we use... Read More »

Computer Architecture Study Guide

Computer architecture provides an introduction to system design basics for most computer science students. Read More »

Network Fundamentals Study Guide

Networking fundamentals teaches the building blocks of modern network design. Learn different types of networks, concepts, architecture and... Read More »