A memory cache is also called a cache store, a memory buffer, or a RAM cache. It is a portion of memory made up of high-speed static RAM (SRAM) instead of the slower and cheaper dynamic RAM (DRAM). Memory caching is very useful because most programs access the same instructions over and over. By keeping as much of this information as possible in SRAM, the computer avoids having to access the slower DRAM.
A disk cache is a technology for improving the time it takes to read from or write to a hard disk. Today, the disk cache is usually included as part of the hard disk. A disk cache can also be a specified portion of random access memory (RAM).