On 10 Jul 98 at 0:49, Chuck Hassenplug wrote:

>   I am running an AMD K6-233 with 64mb SDRAM (two 32mb dimms, bank
> 0-1??) and an AGP graphics card(velocity 128). I have an Award
> Bios, and there are several aspects of it that I need clarification
> on. I would like to know what they are and what they do, and if I
> should enable them or not:
>
> 1)  PCI-VGA palette Snoop

  The palette is a memory table (<1K) on the VGA card, which is used
to translate 256-colour values to RGB.  I believe this option makes
it possible for software to address this table directly as RAM,
rather than go through the register-level interface.  I've never yet
encountered a program that needed to do that, however, so I've always
left it tuned OFF.

> 2)  C-800-CBFFF Shadow, etc.

  These are regions where some peripheral cards may provide code in
ROM.  The idea of shadowing is that the CPU can fetch that code from
motherboard RAM (at 66 or even 100 MHz) much faster than over the PCI
(33 MHz) or ISA (8-10 MHz) buses.  [See #5 below.]

> 3)  Floppy 3 Mode Support

  This is intended to support LS-120 drives, which can operate as
1.44 MB floppy drives, or as 120 MB removables -- and typically
connect as IDE/EIDE devices.

> 4)  Aperture Size - Currently 64m, can go up to 256m????

  In "Real Mode", the CPU can only get at 64K of the VGA frame buffer
at one time, and so many drawing operations include overhead to
obtain access to the 64K containing the pixels of interest.  A lot of
this overhead can be eliminated in "protected mode" by mapping the
entire frame buffer into the CPU's address space, somewhere high in
memory.
  Since video cards with more than 8 MB are still pretty rare, 64 MB
should be adequate for a long time yet.

> 5)  System Bios Cacheable

  This is the same as #2, except that it refers to the system BIOS
ROMs rather than device ROMs.
  There is a claim circulating on the net that it is best to turn
this OFF for NT, that because NT installs its own hardware drivers,
this memory is better left available as needed than dedicated to
shadowing code that is never executed.
  I'm not certain I totally believe that.  For one thing, the amount
of memory involved is small enough that if it makes a difference, you
should install more memory.  And our experience here is that NT
Terminal Server avoids BIOS bugs that show up in NT Server,
indicating that NTS has done a less thorough job of bypassing the
BIOS code than is claimed for it.

> 6)  Onchip USB

  USB is the Universal Serial Bus, a new standard for connecting
low-speed desktop devices -- mice, keyboards, modems, etc.
  Motherboards have been shipping with USB ports for at least two
years, and Microsoft shipped a USB driver for Win95 a while back.
But it's only in recent months that USB devices have begun to show
up, and it turns out that many BIOSes perform their check for an
attached keyboard BEFORE initializing USB support -- i.e., on all but
the latest boards, you may need a regular keyboard in order to boot,
even if you have a USB keyboard.

> 7)  SDRAM Cycle Length
> 8)  SDRAM Bank Interleave

  You may be able to slightly improve performance by experimenting
with these settings.  It's going to depend on the quality of your
SDRAM and your processor's pattern of memory access.
  The key to optimization is measurement.  Get yourself a suite of
benchmarks you like, and collect actual performance numbers.  In
general, smaller cycle lengths should be faster [but watch system
stability], and interleaved should do better than non-interleaved.

> 9)  Memory Hole at 15mb address

  The 80286, 386SX, and 486SLC had an address space limited to 16 MB,
so if one was going to do something like map the video frame buffer
(see #4), the range from 15 MB to 16 MB was the place to do it.
  You should never need to do this on a 386DX, 486 (other than SLC),
or Pentium-class system.

> 10)  Reset Configuration Data

  This will clear the ESCD (Extended System Configuration Data)
memory, so that PnP will re-detect everything from scratch when the
machine is rebooted.  Note that this setting will revert to NO, so
you don't have to go back in and turn it off again.

> 11)  ACPI I/O Device Node

  This is the new generation power-management standard.  See

http://www.award.com.tw/DOCS/Internet/PRESS/97_4_8.htm

for more details.

> 12)  PCI #2 Access #1 Retry

  Well, I don't know everything.

> 13)  AGP Master 1 WS Read

  In theory, the frame buffer for an AGP card is accessible from the
CPU as if it were system RAM.  In practice, it may be necessary to
add a wait state to reads, especially if the CPU is using a 100 MHz
bus setting.

> 14)  UART 2 Mode - Standard, HPSIR, ASKIR

  Many modern motherboards allow the second UART (COM2) to be
re-routed, from the 9-pin or 25-pin electrical connector, to a
connector for an infrared transceiver.  Yours apparently supports two
different infrared standards.
  Some HP printers can receive data via infrared, and some laptops
can exchange data this way.

> Also, the graphics card needs a dedicated IRQ, and I don't know how
> to make sure that it has one.

  I think Award detects and handles this automatically; it's a manual
option on AMI BIOSes.

David G