晋太元中，武陵人捕鱼为业。缘溪行，忘路之远近。忽逢桃花林，夹岸数百步，中无杂树，芳草鲜美，落英缤纷。渔人甚异之，复前行，欲穷其林。 　　林尽水源，便得一山，山有小口，仿佛若有光。便舍船，从口入。初极狭，才通人。复行数十步，豁然开朗。土地平旷，屋舍俨然，有良田、美池、桑竹之属。阡陌交通，鸡犬相闻。其中往来种作，男女衣着，悉如外人。黄发垂髫，并怡然自乐。 　　见渔人，乃大惊，问所从来。具答之。便要还家，设酒杀鸡作食。村中闻有此人，咸来问讯。自云先世避秦时乱，率妻子邑人来此绝境，不复出焉，遂与外人间隔。问今是何世，乃不知有汉，无论魏晋。此人一一为具言所闻，皆叹惋。余人各复延至其家，皆出酒食。停数日，辞去。此中人语云：“不足为外人道也。”(间隔 一作：隔绝) 　　既出，得其船，便扶向路，处处志之。及郡下，诣太守，说如此。太守即遣人随其往，寻向所志，遂迷，不复得路。 　　南阳刘子骥，高尚士也，闻之，欣然规往。未果，寻病终。后遂无问津者。 .
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Automatic Acoustic Management
=============================

Most modern harddisk drives have the ability to speed down the head movements
to reduce their noise output. The possible values are between 0 and 254. 128
is the most quiet (and therefore slowest) setting and 254 the fastest (and loudest).
Some drives have only two levels (quiet / fast), while others may have different
levels realized between 128 and 254.

To be able to use this with hdparm, you will need a current kernel with the -ac patches
applied. Maybe the kernel of your favorite distribution will already include this (SuSE
has it in their current kernel, for example).
Just try to compile hdparm, type "hdparm" and have a look for "-M" in the output. If it 
doesn't appear, your kernel most likely doesn't support it. 

You can get the acoustic setting by typing

	hdparm -M /dev/hda 

To set the most quiet mode use

	hdparm -M 128 /dev/hda

For the fastest setting use

	hdparm -M 254 /dev/hda

Now test different values and try to hear the difference. :-) 

Not all disk drives support this setting - and the speed impacts may also vary between
different manufacturers and models.  

If you see lines like

	kernel: hdb: task_no_data_intr: status=0x51 { DriveReady SeekComplete Error }
	kernel: hdb: task_no_data_intr: error=0x04 { DriveStatusError }

in your syslog, then your harddisk will most likely not support Acoustic Management.

Perhaps you also wanna have a look on the IBM Feature Tool, available at 
http://www.storage.ibm.com/hdd/support/download.htm.

I would welcome any feedback to <gernot@hillier.de>

Gernot

haha - 2025