Simple description of the difference between buffer and cache

1. What is buffer

Buffer (that is, buffers), the simple is to write to the disk IO first written to memory, when reached a certain time or a certain size, and then write to the disk once, this is a process to take!
Data flow: CPU = = "Memory = =" Disk

2. What is the cache

Cache (buffer), simply to avoid a large number of programs to read and write to the disk, we first write the data in the disk into memory, and then the program directly in memory to read the data, is a take the process!
Data flow: Disk = = "Memory = =" CPU

Simple description of the difference between buffer and cache