Date: Sun, 21 Aug 2005 03:12:08 -0400 (EDT) From: "Matthew N. Dodd" <mdodd@FreeBSD.ORG> To: m.ehinger@ltur.de Cc: freebsd-hackers@FreeBSD.ORG Subject: Re: Parking disk drive heads Message-ID: <20050821025614.O84830@sasami.jurai.net> In-Reply-To: <OFCD8781EA.64EF3A3A-ONC1257060.00238B03-C1257060.0023F45F@gateway-inter.net> References: <OFCD8781EA.64EF3A3A-ONC1257060.00238B03-C1257060.0023F45F@gateway-inter.net>
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On Wed, 17 Aug 2005 m.ehinger@ltur.de wrote:
> which is the correct way to park the hd head?
The documentation will refer to this operation as "Unload".
Standby (0xE2) or Standby Immediate (0xE0) would be the only way I can see
to do this. (Sleep performs an unload as well, but is not useful for your
purposes.)
Some of the low power idle modes supported by the Hitachi 5k100 mention
head retraction to the ramp position, which might be of use provided the
feature is widely supported on new hardware.
Many drives support an "Emergency Unload" but it only appears to be
activated by power failure.
Anyhow, here is a snippet that should get you going (on 6.x/CURRENT):
%%%
#include <sys/ata.h>
...
struct ata_ioc_request req;
int fd;
fd = open("/dev/ad0", O_RDONLY);
memset(&req, 0, sizeof(struct ata_ioc_request));
req.u.ata.command = ATA_STANDBY_IMMEDIATE;
req.flags = ATA_CMD_CONTROL;
req.timeout = 5;
ioctl(fd, IOCATAREQUEST, &req);
close(fd);
--
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