The feel of a LispM/List of running machines

Chris Bitmead uid(x22068)
Tue, 06 May 1997 10:52:43 +1000

>If we are going to do an OS that doesn't loose files, we can either
>use a Log-structured filesystem (much work) or we can write all or
>parts synchonously, hurting performance (badly, given today's
>hardware, very badly).

Well, if we're writing an OOFS, then we are basicly writing an OODB,
which means that we basicly just have to take advantage of all the
research that has been done on DB logging.

I suppose log structured file systems use similar principles
anyway. The good thing about OOFS is that there should be less updates
in terms of bytes anyway since an OOFS is more fine grained.

>- tell one single file to be synchronous, without changing all other
>  on the same filesystem

synchronous seems irrelevant for an OOFS.

>- we can tell a directory that is should be open synchronous so that
>  it can't loose file in the same dir. Without constraining the rest
>  of the filesystem's behaviour.

OOFS does not have directories.

>- we can add a function to ask a file where it lives (NFS, NetBIOS,
>  local files, whatever) and then decide how to open it.
>- add a 'append-only' opening mode (what Linux does, because this
>  doesn't require a change to the API, just to the filesystem itself
>  and modifying the single program 'chmod')

append-only is meaningless for an OOFS.