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BIOS hard drive detection issues and EDD spec
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jacks
Aug 28, 2012, 2:15:23 AM8/28/12
to
Hi all,
Well, I know that during POST all hard drives attached to disk controllers embedded in the chipset of a PC are probed and detected.
Now I wanna know, is this true for Hard disks attached to disk controllers on pci expansion cards installed on mobo.
AFAIK, this should not be the case, as the info about such hard drives is not showed in bios setup. But for drives attached to controllers embedded in chipset, the bios shows all the drives detected.
I went through bios enhanced disk drive specs, but I couldn't find any clue.
Can anyone clarify the issue?
Well, I know that during POST all hard drives attached to disk controllers embedded in the chipset of a PC are probed and detected.
Now I wanna know, is this true for Hard disks attached to disk controllers on pci expansion cards installed on mobo.
AFAIK, this should not be the case, as the info about such hard drives is not showed in bios setup. But for drives attached to controllers embedded in chipset, the bios shows all the drives detected.
I went through bios enhanced disk drive specs, but I couldn't find any clue.
Can anyone clarify the issue?
James Harris
Aug 28, 2012, 5:48:16 AM8/28/12
to
needed at boot time. That would include keyboard, display and any
device that might be booted from. (If the BIOS is told that there is
not a plug-and-play OS installed it should configure and start any
other devices too.)
From what I remember (which may be wrong) PCI disks have a class
designator so the BIOS can include within itself a generic driver to
start those disks. The BIOS should thus be able to see and start disks
on PCI expansion cards and probably boot from them too.
It sounds like your BIOS is not seeing the PCI disks. Maybe you have a
BIOS setting to enable or disable attached devices. On some BIOSes it
is possible to turn off certain embedded controllers. Then the BIOS
does not see them but an OS which probes the hardware can still detect
them.
James
jacks
Aug 28, 2012, 6:57:18 AM8/28/12
to
On Tuesday, 28 August 2012 15:18:16 UTC+5:30, James Harris wrote:
> On Aug 28, 7:15 am, jacks <jacks.1...@gmail.com> wrote:
>
> > Hi all,
>
> >
>
> > Well, I know that during POST all hard drives attached to disk controllers embedded in the chipset of a PC are probed and detected.
>
> >
>
> > Now I wanna know, is this true for Hard disks attached to disk controllers on pci expansion cards installed on mobo.
>
> >
>
> > AFAIK, this should not be the case, as the info about such hard drives is not showed in bios setup. But for drives attached to controllers embedded in chipset, the bios shows all the drives detected.
>
> >
>
> > I went through bios enhanced disk drive specs, but I couldn't find any clue.
>
> >
>
> > Can anyone clarify the issue?
>
>
>
> AIUI the BIOS should configure and start any device that might be
>
> needed at boot time. That would include keyboard, display and any
>
> device that might be booted from. (If the BIOS is told that there is
>
> not a plug-and-play OS installed it should configure and start any
>
> other devices too.)
>
>
>
> From what I remember (which may be wrong) PCI disks have a class
>
> designator so the BIOS can include within itself a generic driver to
>
> start those disks. The BIOS should thus be able to see and start disks
>
> on PCI expansion cards and probably boot from them too.
>
>
Yes bios should configure devices on pci expansion cards, but as far as disks are concerned, it seems that the rom of pci controller on expansion card configures the controller and hooks into Int 13h interface, so that system bios writers need not worry about controller specs.
> On Aug 28, 7:15 am, jacks <jacks.1...@gmail.com> wrote:
>
> > Hi all,
>
> >
>
> > Well, I know that during POST all hard drives attached to disk controllers embedded in the chipset of a PC are probed and detected.
>
> >
>
> > Now I wanna know, is this true for Hard disks attached to disk controllers on pci expansion cards installed on mobo.
>
> >
>
> > AFAIK, this should not be the case, as the info about such hard drives is not showed in bios setup. But for drives attached to controllers embedded in chipset, the bios shows all the drives detected.
>
> >
>
> > I went through bios enhanced disk drive specs, but I couldn't find any clue.
>
> >
>
> > Can anyone clarify the issue?
>
>
>
> AIUI the BIOS should configure and start any device that might be
>
> needed at boot time. That would include keyboard, display and any
>
> device that might be booted from. (If the BIOS is told that there is
>
> not a plug-and-play OS installed it should configure and start any
>
> other devices too.)
>
>
>
> From what I remember (which may be wrong) PCI disks have a class
>
> designator so the BIOS can include within itself a generic driver to
>
> start those disks. The BIOS should thus be able to see and start disks
>
> on PCI expansion cards and probably boot from them too.
>
>
>
> It sounds like your BIOS is not seeing the PCI disks. Maybe you have a
>
> BIOS setting to enable or disable attached devices. On some BIOSes it
>
> is possible to turn off certain embedded controllers. Then the BIOS
>
> does not see them but an OS which probes the hardware can still detect
>
> them.
>
I have never seen any hard drive in the bios setup menu which is attached to an pci ide controller on expansion card.
Anyone having similar experiences?
Rod Pemberton
Aug 28, 2012, 10:52:59 AM8/28/12
to
"jacks" <jacks...@gmail.com> wrote in message
news:d269944f-5824-45e0...@googlegroups.com...
...
> Yes bios should configure devices on pci expansion cards, but as far
> as disks are concerned, it seems that the rom of pci controller on
> expansion card configures the controller and hooks into Int 13h
> interface, so that system bios writers need not worry about controller
> specs.
From historical experience, that's what should be done.
The PS/2 technical reference defines the use of the 0xAA55 signature
for expansion ROMs.
A number of other specifications add additional support
or changes to Int 13h, 15h, 18h, 19h:
PS/2 Technical Reference (19h)
Phoenix EDD 1.0 (13h for CHS)
Phoenix EDD 3.0 (13h for 28-bit LBA)
PnP BIOS specification (18h, 19h)
BIOS Boot specification (13h, 18h, 19h)
Enhanced BIOS Services for Disk Drives (13h)
ATAPI Removable Media Device BIOS specification (13h)
ACPI 1.0 specification (15h)
APM 1.0 specification (15h)
I listed the version where I know it because some specifications have many
versions, e.g., for ACPI I know of 12 different versions...
You may also want to locate these:
PCI BIOS Specification
ACPI Specification
APM BIOS Specification
BIOS32 Service Directory Specification
Enhanced Parallel Port BIOS Specificatoin
System Management BIOS Reference Specification
Various BIOS generations added extensions. I've not found documentation in
the form of a specification for many of those BIOS improvements. Other
changes are from specifications. This list repeats some specifications
already mentioned:
IBM PC/AT extended BIOS Int 13h for harddisks.
IBM PS/2 extended the BIOS with EBDA.
The Advanced Power Management (APM) extended BIOS Int 15h.
IBM/MS BIOS Int 13h extensions.
Desktop Management Interface (DMI) extends BIOS.
Phoenix EDD 1.0 extended BIOS Int 13h for CHS translation.
Plug 'n' Play extends the BIOS.
USB added to BIOSes circa '95.
System Management BIOS (SMBIOS) extends BIOS.
Advanced Configuration and Power Interface (ACPI) extend BIOS Int 15h.
BIOS Boot Spec. (BBS) extend BIOS Int 18h/19h, PnP BIOS functions 60-64h.
Y2K BIOS fixes.
Phoenix EDD 3.0 extended BIOS Int 13h for 28-bit LBA.
FYI, my most recent machine (5 years old...) will only emulate hardware for
devices that are actually needed to boot. I.e., if I boot from cd-rom, then
harddisk is not emulated, or vice-versa. I still need to assemble another
machine with parts from a few years ago...
> I have never seen any hard drive in the bios setup menu which is
> attached to an pci ide controller on expansion card.
The last time I saw a harddisk connected to an expansion card was a decade
ago. It was an RLL drive just prior to IDE. Sorry.
Also, I think you should've posted some of your other questions on
comp.os.msdos.programmer here or cross-posted to both, e.g., the questions
about Pnp BIOS or USB BIOS emulation. Or, others may go there now...
Anyway, Ben Lunt just completed a book on USB and Mike Gonta posted about a
universal USB boot image... Typically, you should watch or post to
alt.os.development, alt.lang.asm, and comp.lang.asm.x86 too.
Rod Pemberton
news:d269944f-5824-45e0...@googlegroups.com...
...
> Yes bios should configure devices on pci expansion cards, but as far
> as disks are concerned, it seems that the rom of pci controller on
> expansion card configures the controller and hooks into Int 13h
> interface, so that system bios writers need not worry about controller
> specs.
The PS/2 technical reference defines the use of the 0xAA55 signature
for expansion ROMs.
A number of other specifications add additional support
or changes to Int 13h, 15h, 18h, 19h:
PS/2 Technical Reference (19h)
Phoenix EDD 1.0 (13h for CHS)
Phoenix EDD 3.0 (13h for 28-bit LBA)
PnP BIOS specification (18h, 19h)
BIOS Boot specification (13h, 18h, 19h)
Enhanced BIOS Services for Disk Drives (13h)
ATAPI Removable Media Device BIOS specification (13h)
ACPI 1.0 specification (15h)
APM 1.0 specification (15h)
I listed the version where I know it because some specifications have many
versions, e.g., for ACPI I know of 12 different versions...
You may also want to locate these:
PCI BIOS Specification
ACPI Specification
APM BIOS Specification
BIOS32 Service Directory Specification
Enhanced Parallel Port BIOS Specificatoin
System Management BIOS Reference Specification
Various BIOS generations added extensions. I've not found documentation in
the form of a specification for many of those BIOS improvements. Other
changes are from specifications. This list repeats some specifications
already mentioned:
IBM PC/AT extended BIOS Int 13h for harddisks.
IBM PS/2 extended the BIOS with EBDA.
The Advanced Power Management (APM) extended BIOS Int 15h.
IBM/MS BIOS Int 13h extensions.
Desktop Management Interface (DMI) extends BIOS.
Phoenix EDD 1.0 extended BIOS Int 13h for CHS translation.
Plug 'n' Play extends the BIOS.
USB added to BIOSes circa '95.
System Management BIOS (SMBIOS) extends BIOS.
Advanced Configuration and Power Interface (ACPI) extend BIOS Int 15h.
BIOS Boot Spec. (BBS) extend BIOS Int 18h/19h, PnP BIOS functions 60-64h.
Y2K BIOS fixes.
Phoenix EDD 3.0 extended BIOS Int 13h for 28-bit LBA.
FYI, my most recent machine (5 years old...) will only emulate hardware for
devices that are actually needed to boot. I.e., if I boot from cd-rom, then
harddisk is not emulated, or vice-versa. I still need to assemble another
machine with parts from a few years ago...
> I have never seen any hard drive in the bios setup menu which is
> attached to an pci ide controller on expansion card.
ago. It was an RLL drive just prior to IDE. Sorry.
Also, I think you should've posted some of your other questions on
comp.os.msdos.programmer here or cross-posted to both, e.g., the questions
about Pnp BIOS or USB BIOS emulation. Or, others may go there now...
Anyway, Ben Lunt just completed a book on USB and Mike Gonta posted about a
universal USB boot image... Typically, you should watch or post to
alt.os.development, alt.lang.asm, and comp.lang.asm.x86 too.
Rod Pemberton
James Harris
Aug 29, 2012, 6:11:19 AM8/29/12
to
On Aug 28, 11:57 am, jacks <jacks.1...@gmail.com> wrote:
...
> Yes bios should configure devices on pci expansion cards, but as far as disks are concerned, it seems that the rom of pci controller on expansion card configures the controller and hooks into Int 13h interface, so that system bios writers need not worry about controller specs.
There is a standard for expansion devices to insert themselves in the
boot sequence:
http://en.wikipedia.org/wiki/BIOS#BIOS_boot_specification
The spec itself is not that easy to read but is freely available for
download.
> > It sounds like your BIOS is not seeing the PCI disks. Maybe you have a
> > BIOS setting to enable or disable attached devices. On some BIOSes it
> > is possible to turn off certain embedded controllers. Then the BIOS
> > does not see them but an OS which probes the hardware can still detect
> > them.
>
> It seems that bios menu does not have space for displaying more than 4 drives, which must be attached to controller embedded on chipset.
BIOSes often have a basic setup screen which lists just four specific
drives but then later BIOS setup options allow other drives to be
configured. I guess you have looked carefully for those and for
enabling any ROM-based drivers that might allow access the expansion
card.
> I have never seen any hard drive in the bios setup menu which is attached to an pci ide controller on expansion card.
By the way, your Usenet-posting line length seems way too big which
doesn't help the layout of posts or replies.
James
...
> Yes bios should configure devices on pci expansion cards, but as far as disks are concerned, it seems that the rom of pci controller on expansion card configures the controller and hooks into Int 13h interface, so that system bios writers need not worry about controller specs.
boot sequence:
http://en.wikipedia.org/wiki/BIOS#BIOS_boot_specification
The spec itself is not that easy to read but is freely available for
download.
> > It sounds like your BIOS is not seeing the PCI disks. Maybe you have a
> > BIOS setting to enable or disable attached devices. On some BIOSes it
> > is possible to turn off certain embedded controllers. Then the BIOS
> > does not see them but an OS which probes the hardware can still detect
> > them.
>
> It seems that bios menu does not have space for displaying more than 4 drives, which must be attached to controller embedded on chipset.
drives but then later BIOS setup options allow other drives to be
configured. I guess you have looked carefully for those and for
enabling any ROM-based drivers that might allow access the expansion
card.
> I have never seen any hard drive in the bios setup menu which is attached to an pci ide controller on expansion card.
doesn't help the layout of posts or replies.
James
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