Re: Almost there, but confused about SATA selection in BIOS

Revolt wrote:
"Paul" <nospam@xxxxxxxxxx> wrote in message news:f8ek40$etq$1@xxxxxxxxxxx
Ihatefishsauce wrote:
For Standard IDE, the "Enhanced Mode" is the one you should use,

Yea, this is what I use. No fuss, no muss. But what does the enhanced option do exactly?

AFAIK, it places the storage interfaces in the PCI address space.
Basically, it means a different driver is used. A driver that is
not present in Win98 or WinME. But the driver is available with
the right service pack of Win2K or WinXP (or Vista I suppose).

The "compatible" mode of operation, places the control blocks in
the I/O space. Only four disks can be handled that way, just like
the old motherboards used to have. Old motherboards had two ribbon
cable, for up to four drives. They used INT 14 and INT 15 for
interrupts. The "compatible" mode looks exactly like an old motherboard,
to any OS you are using. That allows an older OS like Win98 to
install its built-in I/O space driver. But it also means you
can only use four disks.

Enhanced mode supports more disks, because it doesn't have to look
like anything. For example, some Southbridges have room for eight
disks, and as long as they all sat in the PCI address space, the
PCI driver(s) could use them. For interrupts, PCI allows sharing
of interrupts, so all of them could be bound to the same interrupt
number.

You can get more info here, better than I can explain it. Note that
they don't write a specific version for every new chipset, and this
doc was only written once, to explain their idea of putting stuff
in the PCI space (at base address register - BAR, plus offset).

"Serial ATA Controller Programmers Reference Manual"
http://www.intel.com/design/chipsets/manuals/25267102.pdf

Paul
.