[ILUG] When servers grow up ....

[Kenn Humborg]

> But there is a lot to be said for a system that retains enough power to
> shutdown gracefully.  It's a common feature of critical systems that you
> retain power, in a rechargeable battery  or so, just enough that
> everything is left in a safe state.

VAXen took this pretty seriously.  The big (i.e. non-workstation,
non-MicroVAX class) VAXen had a battery that would preserve 
the contents of RAM for a while (don't know how long, but at 
least minutes anyway).

Then, when booting, VMS would check if it was previously shutdown
properly or because or a power failure and, if so, was RAM still
valid.

If RAM was OK, it would pretty much continue where it left off.
Any device drivers with in-progress I/O requests would be 
notified and they would do whatever was necessary to make sure
their device is back on line and re-do the request.  If an 
app wanted to know if a power recovery occurred, they could 
register with the OS to get a notification during the later
stages or powerfail recovery.

Basically, the hardware, the OS and the drivers all co-operated
to make sure that enough state was preserved to recover
properly.

_That's_ what happens when servers grow up.  

<RANT>
Of course, this was over 20 years ago, so I'm sure the 
Intel-based world will consider it such ancient history
that there's no way they'd add features like these to their 
servers and OSes.  Like, VMS is _so_ passe...
</RANT>

Later,
Kenn