[Info-vax] Byte range locking - was Re: Oracle on VMS

[David Froble]

BillPedersen wrote:

> Well we do not yet have Postgres on VMS.  There are a couple stumbling points
> that have gotten in the way.  Shared Stream IO to files to allow multiple
> writers and byte-range locking in the same context as the SSIO.  There are
> two features  which several "data" sharing applications running on Linux/Unix
> quite often have in common and they are the biggest stumbling points of
> getting these sorts of software to run on VMS effectively.

I guess my first question is, how does *ix do byte range locking?  There is 
nothing special about locking between cooperating tasks.  Just needs a good 
design, and then implementation.  With the initial help of John Santos I've 
implemented a locking system.

The reason I've asked how *ix does the job is that it's my impression that to do 
other than agreed upon fixed length data locks, it seems that otherwise would 
have to know a bit more about the data.  That's a bit different from what I've 
done in the past, and how the VMS DLM works.

Got any specifications?