+#define SATA_LBA_COMPONENT(lba, offset) ((((lba) >> (offset)) & 0xff))
+
+#define ATA_IDENTIFY_DEVICE 0xec
+#define ATA_IDENTIFY_PAKCET_DEVICE 0xa1
+#define ATA_PACKET 0xa0
+#define ATA_READ_DMA_EXT 0x25
+#define ATA_READ_DMA 0xc8
+#define ATA_WRITE_DMA_EXT 0x35
+#define ATA_WRITE_DMA 0xca
+
+#define MAX_RETRY 2