On 4 Feb 2001, at 1:50, Steve wrote:
> >"Alexander Kruppa" wrote:
> >
> >The screen-saver idea is important for another reason.
> >I asked several coworkers and secretaries to let Prime95 (NTprime,
> >actually) run on their PCs and they agreed, but they were less than
> >happy when I asked them to change the pretty 3-d screen savers for
> >something that lets NTprime have more cpu power. With the selection
> >Microsoft offers right now, that means "Blank Screen" or "Marquee" -
> >neither is extremely exciting to watch. Before long, most of them went
> >back to the old screen savers and NTprime slowed down to a halt.
>
>
> "...slowed down to a halt" is no exaggeration. I've seen screensavers slow
> it down to more than 7 seconds per iteration at 800+ MHz. I have it running
> on some PCs where the user has the screensaver set to start after 5 minutes
> then sets the power management so the monitor turns off after 10 or 15
> minutes... and what really bothers me is that the screensaver continues to
> run even with the monitor off. (Is there some way to prevent that which I
> don't know about?)
Not that I'm aware of, either. You're supposed to use ACPI to make
the processor sleep rather than worry about details such as whether
the screensaver is still running with no visible display.
> One idiot even had her settings such that the screensaver
> didn't start until _after_ the monitor went off.
No accounting for stupidity! I wonder if you could get away with
tricking users like this into staring at the "blank screen" saver for
hours on end by fooling them that, very occasionally, something
"interesting" happens? ;->
>
> There are so many screensavers available now that one can be found to match
> any personality, and I have found it impossible to get people to let go of
> one they really like. So I don't believe Brian's idea will do very much
> good; but then every little bit helps.
Could I respectfully point out that the windoze screensavers run at
priority 4. If you raise Prime95/NTPrime's priority to 4, you will
split CPU time more or less evenly between the screensaver and the
Mersenne client. In fact there should be a bit more going our way
than the screensaver does; the screensaver does voluntarily
relinquish the CPU occasionally - otherwise a client running at
priority 1 would get nothing.
On the principle that half a system is better than nothing, this
trick is probably worth publicising, if it will let users keep their
favourite screensaver running.
I'd warn strongly against raising the priority of Prime95/NTPrime any
higher than 4, as there could be serious consequences to the
performance of foreground tasks.
BTW, and getting way off topic, on windoze I use a freeware gadget
called Sleeper which I downloaded from the net ages ago. Still works
on Win2K though. This has "hot spots" in two corners of the screen
(configurable in size and which two corners are used); if you park
the mouse pointer in one of the "hot spots", the screensaver
activates "immediately" (actually there is a 2 sec delay) whilst
parking the mouse pointer in the other "hot spot" prevents the
screensaver from ever activating. If the mouse pointer is elsewhere,
the screensaver activation is normal (as if Sleeper were not
present).
I use this (in conjunction with the screensaver password feature, and
the standard "blank" screen saver) as a security tool, to lock access
to my system through the console when I'm temporarily absent e.g.
gone for a leg stretch. Obviously you need to set the BIOS boot &
setup passwords as well, to prevent people from breaking in by simply
resetting the system. And, no, it isn't perfect, but then no security
system is.
The "never activate" feature is also useful, as it prevents
screensaver activation from interfering with tasks like scandisk and
defrag which don't take kindly to anything happening which causes the
volume being processed to be accessed.
Sleeper is tiny and has no detectable processing time overhead.
Obviously it does need to steal a few cycles, but it really isn't
significant, even on a slow system.
Regards
Brian Beesley
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