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- Some of questions !? (scsi)
- Majki Majk
October 1, 2008, 8:24 am
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Sometimes when booting scsi controller with disks on it, boot loads the
disk ID but the speed next to it is 40(i presume mhz), but it would need
to be 160mhz, because the disks are U160, and the controller the same.
Some of my disks are willing to show U160 speed.
I have another issue, have an old controller for 50pin devices, and the
SCSI CDRom on it. I wanted to boot some Cds from it but couldn't do
it...it always said no "Scsi bios loaded" when loading controller or
something like that. Controller showed installed and with XP drivers
loaded so it works, but won't boot from it. Do You maybe know how to
adjust it to boot cds. Don't know maybe something with the jumpers but
doubt it. In computer bios, i had adjusted it for Boot from :SCSI device
first, CDROM, HDD...or somthing like that, SCSI was first surely.
Thanks for advices.
Re: Some of questions !? (scsi)
Majki Majk wrote:
For the first question, you would need to describe the SCSI chain fully,
for someone to help you. Every component counts, when it comes to making
a fully functional chain. It is possible to mix narrow and wide devices,
put the wrong type of termination on the chain, and so on.
Add-in cards have a BIOS chip soldered to them. An INT 0x13 routine is
loaded from that chip, to support booting from the controller card.
There is a limited defined area in low memory (128KB of RAM) for
the add-in card BIOSes to load. If you run out of that memory,
then a ROM may refuse to load. And in the case of your SCSI card,
the ROM may unload if the code thinks no devices are present.
If the ROM won't load, you cannot boot from the card.
Here is a reference on the topic of Expansion ROMs on RAID cards and the
Formatted for clarity:
Q: Why doesn't the BIOS (Option ROM) for my PCI device show
during boot up?
A: The cause of the problem is that in order to be PC Compatible,
the Option Rom space is limited to 128K. This is true for any
motherboard with PC compatible BIOS'.
In the common configurations, a newer AGP card (such as any
GeForce4) will require 64K of Option Rom space, so you have only
64K of Option Rom space left to work with for other devices.
Many SCSI, NIC (w/ PXE), IDE Raid and etc., can easily use
another 40 to 64K of Option Rom space for their needs.
By design the Option Rom should shrink down to a smaller run time
code after the initialization code has run. For example, some Adaptec
cards will require 32K to initialize. Then they shrink down to
12K at run time; whereas some GeForce4 cards require 64K to initialize
and never release to a smaller amount. Please check with the device
manufacturer for the latest firmware upgrade or ask if they have a
smaller Option Rom available. Again this is a limitation of the
PC compatible specification and not a failure of the motherboard
Re: Some of questions !? (scsi)
In checking some Adaptec U2W info, see if any of the following points help:
1. The SCSI card typically is set to an ID of " 7 " ( your card may
(SCSI ID 7 has the highest priorty on the SCSI bus)
2. The device to be booted from should have an ID of " 0 ";
Check to see if the CDROM is set to " 0 ".
3. The Boot Target ID setting for the SCSI card should be set to " 0 ".
During the boot process, the SCSI cards' BIOS can be modified by
using a one or two key sequence ( for Adaptec, it's CTRL-A ).
4. Once in the SCSI cards' BIOS, there should be setting for setting
the Maximum Transfer Rate ( or something similiar ). This setting should
be the equal to the CDROM's transfer speed specification.
5. There should be a setting to enable the SCSI cards BIOS at boot up.
(Adaptec : Host Adapter BIOS = Enabled )
6. There should be a setting to enable support for bootable CD-ROMs.
(Adaptec : BIOS support for Bootable CD-ROMs = Enable )
7. There should be a setting to enable INT 13 extensions..
(Adaptec : BIOS support for INT 13 extensions = Enable )
Hope this helps.
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