On Tue, May 18, 2010 at 7:13 PM, Glynn Clements <glynn@xxxxxxxxxxxxxxxxxx> wrote: Thanks for the clarification . Need some further clarification... > > query wrote: > >> I want to know enable 32-bit IO-support on my SATA hard drive >> using hdparm . But before I enable 32-bit support , I want to know >> whether my hard drive supports 32-bit IO or not. > > The term "32-bit I/O" relates to communication between the CPU and a > PCI IDE controller. "The hdpam man page say "32-bit" refers to data transfers across a PCI or VLB bus to the interface card only ". So , here does the interface card is referring to the CPU. > The concept isn't meaningful for an on-board controller. By On-board controller do you mean to say hardware RAID device or SCSI devices and we don't have to set IO parameter in such devices. > > As for communication between the controller and the drive, a parallel > ATA interface is 16-bit, while SATA is serial. > >> * 48-bit Address feature set >> (is it telling that the disk supports 48-bit IO) > > No, it's stating that the drive supports 48-bit LBA addresses. The > original IDE standard used 28-bit addresses which limit the size of > the drive to 137GB (2^28 512-byte sectors). With 48-bit addressing the limit is 144 petabytes . So , does that mean we can install hard drive of capacity 144 petabytes if disks of such size are available and the BIOS supports it. Can BIOS put a restriction on the maximum capacity of hard drive we can install . Thanks again . Bz > > -- > Glynn Clements <glynn@xxxxxxxxxxxxxxxxxx> > -- To unsubscribe from this list: send the line "unsubscribe linux-admin" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
