This character-mode Linux device-driver lets an application program read from (or write to) the computer system s video display memory -- bypassing any software windowing systems. -This character-mode Linux device-driver lets an application program

Linux设备驱动程序，用途是虚拟一段内存空间为设备驱动程序空间，在此段空间实现读写设备驱动程序。-Linux device driver, uses a memory space for the virtual device driver space, space to achieve during this read-write device drivers.

通过mmap实现进程间共享内存的读与写，linux下运行-use mmap to read and write share memory of thread，in linux

Memcached 是一个高性能的分布式内存对象缓存系统，用于动态Web应用以减轻数据库负载。它通过在内存中缓存数据和对象来减少读取数据库的次数，从而提高动态、数据库驱动网站的速度。Memcached基于一个存储键/值对的hashmap。其守护进程（daemon ）是用C写的，但是客户端可以用任何语言来编写，并通过memcached协议与守护进程通信。(Memcached is a high-performance distributed memory object caching system