RE: locks and trust (Re: Rejected Requirements)

>I have a feeling we're talking past eachother here. In fact, I'm not at
>all sure who I agree with and who I disagree with because I'm not clear on
>who is using what terminology. It seems to me that locks can vary along
>at least four orthogonal axes:
>
>mandatory/advisory
>exclusive/shared
>read/write/both
>privilege

I've been representing the language in the current lock draft.  In this
draft, the terms "mandatory and advisory" are not used as modifier of lock
semantics.  From past discussions on this list, and past personal use of
the term, and advisory lock is extremely similar in meaning to the current
shared lock.  I'm not sure what is meant by mandatory.  I'm also not sure
what is meant by privilege.

The axes of variation for locking in the current lock draft are:

exclusive/shared
write/(potential expansion to other access control verbs)

Thus there is an exclusive write lock, and a shared write lock.

Since a lock mediates access to a resource among principals with equal
access permissions, a lock is constrained by access control.  A super user
administrator could have sufficient *access* permissions to be able to
remove any given lock.  But this is a special access permission, not a
special lock type.

- Jim

Received on Monday, 2 June 1997 14:11:47 UTC