Re: What is a disk arm?

[Buck Calabro <kc2hiz@xxxxxxxxx>]

On 6/14/2013 10:18 AM, Charles Wilt wrote:
> > From the page...
>
> "The following formula shows a worst case scenario.."

Understand and agree.  I need to plan for the worst case, don't I?  I
can't control how dirty the main store pages will be when the next
tornado blows through. :-(

> Also
> "The amount of time required to shut down a system typically is a small
> percentage of this value."

Yes, quite true, and borne out by actual PWRDWNSYS commands on this very
machine.

> Lastly it's important to realize you aren't doing a "suspend" as is the
> case with a Windows PC.  With a suspend in the PC world, all you are doing
> is writing out a copy of the memory to a reserved section of the disk.
>  With the i, you are updating all the objects on disk that have dirty pages
> in memory and doing additional house keeping as required.  Not to mention
> you are ending all jobs...

I'm not trying to do an IBM vs Windows comparison.  It would be nice to
have the machine write that 32GB to a reserved area on disk and have the
next IPL update the dirty objects during startup when (typically) the
power situation has stabilised rather than take the time to do it during
a power-induced shutdown.  Maybe the Power 8 machines will do that, who
knows?  The platform keeps getting better and better.  I've left reader
feedback so that the documentation can get better too.
  --buck