[syslinux] Locally attached disk is seen, 40 gig PATA in USB enclosure is not.

Gene Cumm gene.cumm at gmail.com
Sun Apr 5 20:06:14 PDT 2009


On Sun, Apr 5, 2009 at 5:01 PM, Chris Miller <Chris at infogreat.com> wrote:
> Hi Gene,
>
> Please see interlinear comments.
>
> Chris.
>
> Fill what's empty, empty what's full, and scratch where it itches.
> Life is a journey, not a destination ...
>
>
>
>> In the future, also take a look at /proc/kallsyms.  This
>> shows all symbols from modules and compiled in code in the
>> kernel.  Few kernels are compiled with the USB storage
>> symbols built into the kernel.  If you know the name of a
>> kernel module file (ie usb-storage.ko), you can search for
>> its symbols (look like usb_storage).  This is a great
>> suggestion for any time you can't find a storage device once in Linux.
>>  Most kernels have PATA (IDE) support compiled in but
>> sometimes USB, SCSI, or SATA (especially AHCI or IRRT) may
>> not be available immediately, especially when it's a newer
>> controller (AHCI and IRRT controllers fall here) and/or an
>> older kernel or less common controller.
>>
>> In my system, the line looks like:
>> ffffffff88645880 d usb_storage_driver   [usb_storage]
>>
>> The bracketed name I believe means that it came from a module
>> and is not built into the kernel.
>
> I am dealing with at least two kernels -- EXTLinux and ISOLinux -- and
> possibly three if ISOLinux is booting something else that is shepherding the

EXTLINUX, ISOLINUX, PXELINUX and SYSLINUX are all boot loaders and
have no relevancy to the kernel except that they load the kernel into
memory such that the kernel can then run.  In your extlinux.conf file,
the kernel is the file named "/boot/Fedora-10/isolinux/vmlinuz", a
compressed kernel, most likely using bzip2.

> installation.  EXTLinux is, as nearly as I can tell, monolithic.  I can't
> find any sort of initrd for it that I can modify.  And ISOLinux, which has
> an initrd.img already is including the USB module, as nearly as I can tell.
> Investigating this is tricky because after gunzipping the cpio archive and
> restoring the cpio archive, the symlinks sometimes link to the running
> system ...  So, for example, mtab showed mounted filesystems that I knew
> could not have been mounted because they were mine.  mtab was a symlink
> pointing to my running /proc... hierarchy.

You should be able to extract the contents of the CPIO archive to its
own directory such that you shouldn't have things like this happening.

> Can you please give me instructions how to determine the answer to your
> question, and I will do it.  It is possible that you are right and there is
> only one way to find out.

In order to examine /proc/kallsyms, you must have your system running
a Linux kernel, like the installer kernel that you're using in the
Fedora Core 10 installer.  Once in the installer, you should be able
to change to an alternate virtual console (Alt-F1 (or Ctrl-Alt-F1 if
in an X session) changes to VT1.  Alt-F2 (or Ctrl-Alt-F2) changes to
VT2) and check what modules are loaded and possibly try to load the
usb-storage module.  "modprobe usb-storage" should load it if it is a
module that is available.  In addition to the USB storage driver,
you'll also need the HCI (Host Controller Interface) drivers (ohci or
uhci and preferably also ehci if USB 2.0).

"lsusb" if available is also a good idea to get a human readable list
of USB devices that are connected.  They may not have a driver
connected but this indicates that the USB host drivers are loaded and
that the USB stack sees the device.  Otherwise, you'll have to
manually examine the /proc file system.

> Thanks for your help.

Hope this helps clarify.  I'm sorry if I may have provided a little
too much info initially leading to some confusion.

I agree with Shao in that it's probably more about the capabilities
(or possible lack there of) of the Fedora Core 10 installer.  I'd
suggest trying to search for installing FC10 from a USB stick to get
some pointers, or at least a stepping point.

-Gene




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