Re: Explaining single level store to non i people

[Lukas Beeler <lukas.beeler@xxxxxxxxxxxxxxxx>]

On Tue, Aug 18, 2009 at 17:03, Nathan Andelin<nandelin@xxxxxxxxx> wrote:
> Take the idea of multiple users running the same application, but each instance of the application in a separate process. ÂThere may be many jobs running, but never more than one instance of application code and data in memory under SLS, which IIRC greatly reduces the conventional overhead of each process allocating its own space for code and data, and the conventional overhead of switching between jobs.

Any modern operating system shares it's dynamic libraries and
application images in memory on a Copy-On-Write basis. Of course it's
not as neat to implement as in an SLS system, because there's some
overhead associated with it.

All these optimizations might've been a big advantage back in the days
where NT4.0 was in use. But these days are long gone - even if you get
a 5% memory usage improvement compared to a System x machine running
Windows or Linux, it'll still be loads cheaper to just double the
memory in the System x machine, as System x memory is roughly a
quarter of the price (while, of course, being technologically
identical).