Minimum set of primitives?
Fri, 20 Mar 1998 02:02:01 +0000
> - some applications require durability -- that is, once they receive and
> acknowledge a piece of data, they're expected not to lose it, even if the
> machine gets unplugged immediately. The need for this is obviously
> strongest in the case of business applications, but it's nice even for
> personal-use applications. This means that applications have to have
> some control over when their data gets written to disk.
> I'm not familiar with how historical Lisp systems or KeyKOS handled
> these problems, but I suspect they are solved problems. Perhaps my elders
> here can point us at some documentation.
> (Well, KeyKOS handles the last one by offering a 'journal page' system call,
> which forces a page to be written to disk immediately. Database servers can
> force a write on the page containing their latest log entry after each time
> they make a log entry. I'm not clear on how a Lisp system could handle this.)
Yes, I can't see how you can get away from the need for a
"commit" function, which says to the system that the current
state is a place that can be recovered from if things crash. Of
course not all applications will care to use it, but some will
definitely need it, maybe even most.