Dave McGuire wrote:
I've heard little tidbits about it, but nothing
very detailed...can
you describe it when you have a moment?
-Dave
Single Level Store:
- The operating system and all user processes share a single large
address space.
- There is no filesystem: every database table, user profile, etc. is
addressed by a pointer in this very large address space.
This seems insane, but it works. There are a few things that make it
work better:
- database tables, user profiles, etc. are all well defined data
structures. They are referred to 'objects', although I don't really
think it is object oriented.
- There is a lot of pointer checking going on to prevent overruns and
accessing data that isn't yours.
- Pointers are 'tagged' by the operating system to indicate if they are
legitimate (ie: blessed by the OS and secure). If a user somehow
manages to change a pointer in a non-blessed way, the 'tag' is lost.
The old 48 bit CISC architecture (IMPI) was quite a weirdy compared to
modern architectures. The current 64 bit PowerPC based processors are
much more 'normal' looking.
The 'Advanced/36' was the first use of a 64 bit PowerPC based AS/400.
Kind of funny to think about. :-)
Mike