SAN JOSE ( ChipWire) -- In advance of the Developer Forum to be held over the nextweek, Intel Corp. has released the greatest amount of detailed technical
information to date on its IA-64 architecture. Perhaps most interesting is new
firmware Intel has included that will enable OEMs to differentiate their IA-64
servers from one another.
The architecture will see its first realization in the Itanium -- formerly Merced --
and McKinley microprocessors.
The Intel documents provide some interesting hints at new tacks that Intel is
taking as it embraces the 64-bit world. One of the seldom-discussed, but most
interesting, technical areas is the interface between the processor and the
Traditionally, firmware has been called BIOS, which stands for Basic Input/Output
System. It's a term taken from the early days of the PC, and it's currently used to
refer to the low-level software used to get a system started and to interface the
basic hardware with the chip's control software.
Firmware in the IA-64 architecture has grown greatly in complexity. From
relatively well-contained modules in Intel's 32-bit architectures, IA-64 firmware has
become a three-tentacled technical beast that connects the basic Itanium or
McKinley microprocessor to Windows or Unix-like operating systems.
The three IA-64 firmware layers comprise the processor abstraction layer (PAL),
system abstraction layer (SAL) and extensible firmware interface (EFI).
Intel's lone PAL
The PAL has been developed by Intel and will be delivered along with the Itanium
to IA-64 OEMs who plan to build systems around that chip. However, those
OEMs are expected to provide the SAL and EFI firmware themselves.
According to an Intel technical document, "The PAL layer is developed by Intel
and delivered with the processor." The SAL and EFI firmware are developed by
the platform manufacturer and provide a means of supporting value-added platform
features from different vendors.
That's a double-edged sword, at least one expert familiar with the situation said.
On the one hand, OEMs building IA-64-based systems must grapple with writing
two of three layers of new boot code. On the plus side, that gives them the
opportunity to differentiate their systems -- something they're going to have to do
if they're going to stand out in a field crowded with Itanium- and McKinley-based
servers. It's known that Hewlett-Packard Co. and IBM Corp., among others, are
working hard to differentiate their IA-64 offerings. HP has already alluded to work
that would encompass proprietary boot code.
In general, IA-64 processors such as the Itanium boot at a different location than
IA-32 Pentium-family chips. That necessitates some mild gymnastics in those
cases in which the Itanium runs legacy IA-32 code. All the IA-64 chips are
supposed to run 32-bit Pentium software without the need for advance
recompilation or porting of any sort.
According to Intel's technical documents, IA-64 chips execute PAL firmware to
test and initialize the system and then continue execution in the IA-64 instruction
set to boot the system -- something that obviously can't be done on a Pentium.
However, the next layer of firmware, SAL, can switch to the IA-32 instruction set if
needed to run IA-32 BIOS code.