Re: ramdisk/tmpfs/ramfs/memfs ?

[Christoph Rohland <cr@sap.com>]

Hi Padraig,

On Fri, 27 Apr 2001, Padraig Brady wrote:
> I don't have swap so don't need tmpfs, but could probably
> use it anyway without a backing store? 

Yes, it does not need backing store.

> Anyway why was ramfs created if tmpfs existed, unless tmpfs requires
> backing store?  They both seem to have been written around the same
> time?

- shm fs was written as a specialized fs to implement POSIX shared
  memory based on SYSV shm.
- ramfs was introduced shortly after shm fs and was meant as a
  programming example for a minimal virtual filesystem. 
- Later shm fs was redone to use the same methods like ramfs but still
  was only useable for shared memory.
- After the release of 2.4.0, I extended shm fs to support read/write
  and thus be tmpfs and since then it can replace ramfs.

Greetings
		Christoph