# ATA or SCSI CDB



## trutlze (Jan 20, 2013)

Hi,

can anyone point me to a page or somewhat where "ATA or SCSI CDB" commands are listed or explained?

A HDD in a laptop makes strange noises from time to time and I thought it might be some kind of power-saving setting that causes it. So I searched a little and found some pages where they pass "camcontrol() cmd" commands to the device.

For example the following command should output the power state of ada0

```
camcontrol cmd ada0 -a "E5 00 00 00 00 00 00 00 00 00 00 00" -r -
```

These commands seem to be hex-codes, but I don't know what they mean, so I won't pass them to the device. I searched for some explainations of these codes, but I didn't find any page. One guy wrote that these commands are device-specific, so you need to read the device's specifications. Is this true or are there any standards? Could you help me?



Thanks


----------



## wblock@ (Jan 20, 2013)

sysutils/ataidle can enable or disable some annoying drive behavior.  Since it works on many drives, I'd say those particular commands are standard.


----------

