cvs commit: src/sys/kern subr_param.c

Nate Lawson nate at
Mon Nov 8 12:05:56 PST 2004

Kevin Oberman wrote:
>>Date: Mon, 8 Nov 2004 18:50:33 +0000
>>From: Paul Richards <paul at>
>>Sender: owner-cvs-all at
>>On Sat, Nov 06, 2004 at 04:03:12PM -0800, Kris Kennaway wrote:
>>>On Sat, Nov 06, 2004 at 03:50:06PM -0800, Nate Lawson wrote:
>>>>I was traveling out of the country so I didn't get a chance to comment. 
>>>> The two caveats I'm aware of is a slight loss in processes that are 
>>>>CPU bound and an audio hum from ACPI CPU idling.  The latter is rather 
>>>>interesting actually.  At hz=100, it's just a quiet low buzz but at 
>>>>1000, it is readily audible on many laptops and annoying.  Windows uses 
>>>>hz=1000 too and has the same problem.  I believe it's related to the 
>>>>capacitors and other devices charging/discharging when clocks are stopped.
>>>Can we play music by modulating the value of hz? :)
>>I remember some code for the Commodore Pets that you could use to play
>>notes on a nearby radio by tweaking some spinning loops. Quite a neat
>>trick at the time since there wasn't any sound hardware.
> Actually, this technique predates the PET by any years. I know that we
> could play music on the PDP-1 and that goes back to the late '05s or
> early 60's. I did it on my PDP-11 in the early '70s. I also heard a CDC
> MASStore tape system played as an organ by adjusting the tape movement
> in the vacuum columns.

Ok, this is way off-topic but here's what you can do with a printer 
flash mod to play print head, carriage return, and error beeper:


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