Re: [Syllable-kernel] more on EROS and KeyKOS..

[Daniel G. <da...@fp...>]

On Fri, 2005-01-28 at 08:31 -0800, Jake Hamby wrote:
> Since I have read a lot of the EROS documentation and found it pretty 
> cool, I thought I'd write a quick summary.  As a working open-source OS, 
> it is still basically limited to "Hello, world", but the concepts behind 
> EROS are very cool and were in fact proven by KeyKOS which was a real 
> commercial OS for S/370 mainframes sold by a company called Key Logic 
> during the 1980s.  You can read more on EROS concepts here:
> 

<snip concepts>

On the whole, an interesting idea.  Unfortunately, I believe it dates
itself.  Memory is way to large to be written to disk every 30 seconds.
On my laptop, for example, it takes almost 30 seconds just to write the
1 GB of RAM to disk during suspend!  Granted, it could probably be
faster than that, but a fast application can already dirty memory faster
than it can be written to disk with full-time streaming writes (think
video capture).  I think our secondary storage is just too slow at the
moment, asside from even the problems of it being way to large.

Still, it's an interesting concept.

The "never reboot the OS" can be done now, with suspend-to-disk, both on
Linux and on Windows.  It's not a problem at all.  In fact, I use
suspend-to-ram on Linux on my laptop, and never reboot, except to change
kernels (which you would have to do, even with that design, I believe,
or never change in in-memory representations of data... which would be
very restricting).

Once Syllable has suspend-to-disk, we could just checkpoint (ie,
suspend-to-disk with immediate resume) every so often, and gain most of
the capabilities of this model, I believe.  Especially if
suspend-to-disk is fast.

Daniel