On Mon, Jul 04 2005, Jens Axboe wrote: > On Mon, Jul 04 2005, Lenz Grimmer wrote: > > -----BEGIN PGP SIGNED MESSAGE----- > > Hash: SHA1 > > > > Hi, > > > > Jens Axboe wrote: > > > > > It isn't too pretty to rely on such unreliable timing anyways. I'm > > > not too crazy about spinning the disk down either, it's useless wear > > > compared to just parking the head. > > > > Fully agreed, and that's the approach the IBM Windows driver seems to > > take - you just hear the disk park its head when the sensor kicks in > > (you can hear it) - the disk does not spin down when this happens. > > > > Could this be some reserved ATA command that only works with certain# > > drives? > > Perhaps the IDLE or IDLEIMMEDIATE commands imply a head parking, that > would make sense. As you say, you can hear a drive parking its head. > Here's a test case, it doesn't sound like it's parking the hard here. ATA7 defines a park maneuvre, I don't know how well supported it is yet though. You can test with this little app, if it says 'head parked' it works. If not, it has just idled the drive. #include <stdio.h> #include <unistd.h> #include <fcntl.h> #include <string.h> #include <sys/ioctl.h> #include <linux/hdreg.h> int main(int argc, char *argv[]) { unsigned char buf[8]; int fd; if (argc < 2) { printf("%s <dev>\n", argv[0]); return 1; } fd = open(argv[1], O_RDONLY); if (fd == -1) { perror("open"); return 1; } memset(buf, 0, sizeof(buf)); buf[0] = 0xe1; buf[1] = 0x44; buf[3] = 0x4c; buf[4] = 0x4e; buf[5] = 0x55; if (ioctl(fd, HDIO_DRIVE_TASK, buf)) { perror("ioctl"); return 1; } if (buf[3] == 0xc4) printf("head parked\n"); else printf("head not parked %x\n", buf[3]); close(fd); return 0; } -- Jens Axboe - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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