Arrigo Triulzi wrote:
> “Digital UNIX has two paging modes, lazy and conservative. Conservative means that paging space is allocated as memory is allocated, guaranteeing that there is always somewhere to page to. This limits VM to the size of the paging partitions, but makes for a very robust system. Lazy is more like what people are used to with Unix - paging space is allocated when needed for paging out, you can run more jobs, but you're in big trouble when everything fills up.
My recall is that 4.2BSD would only give you (writable) memory it
could allocate swap space for.
I think of the penchant for "overcommitting" memory
(and the cold hand of the OOM killer) as Linuxisms
Yes, this is the case for Ultrix, and I can imagine that it survived into Tru64 (I don't have my Alphaserver up right now). You need to have disk space allocated to swap for any memory that you want to map, regardless of how much physical memory you have.
-Henry