[clug] Re: Ubuntu 7.04

[Rodney Peters]

It appears that bootloaders Isolinux & GRUB work for booting from flash 
devices  System Rescue CD uses the former and IPCop the latter.

IPCop have a script, mkflash, which is run with the CF card plugged into a 
reader in a conventional desktop system.  It contains the high level commands 
to set up GRUB on the CF device so that it will boot when it is transferred 
to the embeded mobo.  You could probably modify this script for Feisty.

"info grub" provides a good description of how GRUB works although it no 
longer documents the bytes used in the MBR.  If you do need to go 
hex-editing, that detail is said to be in the source code for GRUB. 


HTH,

Rod

On Monday 30 April 2007 22:00, linux-request at lists.samba.org wrote:
> Re: [clug] Ubuntu 7.04
>  From: Robert Edwards <bob at cs.anu.edu.au>
>  To: Michael Cohen <michael.cohen at netspeed.com.au>
>  CC: linux at lists.samba.org
>
> Thanks for the replies.
>
> I have set up various Linuxes in the past to boot from a CF card on an
> IDE bus (especially on mini-ITX mobos). That works fine, as Michael
> says, it just looks like a regular /dev/hdx to the BIOS and to the
> kernel.
>
> One thing that can cause a problem is that write speed on a CF card can
> be a whole lot slower than on a regular hard drive and can also "wear"
> the flash memory chips. So it is a good idea to use a non-journalling
> file-system (like ext2) and to turn off access time updating (with the
> "noatime" option to mount in /etc/fstab). This seems to noticably speed
> up the system.
>
> Another "trick" I use is to use a RAM-based root filesystem (from
> initrd) and to mount stuff like /home, /var and /usr (read-only) from
> the drive. Requires some fiddling to work with a standard distribution.
>
> Anyway, what I was hoping for was any good references to what the BIOS
> is actually looking for on the USB memory device in order to boot from
> it. I have determined that it needs to be a VFAT (or FAT) filesystem,
> but where does the kernel need to be and what bootloader works? Has
> anyone found any good references on how to "roll your own", or a script
> that does it for you?
>
> Cheers,
>
> Bob Edwards.
>
> Michael Cohen wrote:
> > Rodney,
> >   I have a CF/IDE adapter which makes the CF look exactly like a hdd. It
> >   connects to a regular PATA cable. I think its nothing but a connection
> >   adapter because the CF itself supports ATA and appears like an IDE
> > device. This kind of CF device will always boot because as far as the
> > mobo is concerned its a hdd. Similarly installation on it is identical to
> > installing on a hdd. (only caveat is i think it does not support slave
> > mode so you can only have one of those per bus)
> >
> >   I think if you do a google for a CF/IDE adapter you could get some
> > options. If you like I can try to find its exact model
> > number/manufacturer. I think it cost about $20 quite a few years ago.
> >
> >   Michael.
> >  
> >
> > On Sat, Apr 28, 2007 at 05:37:58PM +1000, Rodney Peters wrote:
> >> I have not done this, but the IPCop firewall supports running from CF,
> >> without a HDD.  Their docs, available from http:// www.ipcop.org, give
> >> an overview of the installation process.  However, they are confining
> >> their discussions to those  mini-ITX style mobo which have a CF slot on
> >> board in lieu IDE connector.
> >>
> >> If you install and setup GRUB on the CF drive, then notionally the
> >> kernel should be bootable (however, the syntax of the "kernel" command
> >> would depend on whether the CF drive is seen as sda, sdb etc).
> >>
> >> You would still be up against what boot devices the BIOS supports.  On
> >> my recent mobo, a message appears during POST indicating which "hot-key"
> >> to press to get a menu of boot devices.  For my mobo (both Award-Phoenix
> >> BIOS), pressing Esc and F11 respectively brings up a menu of all
> >> bootable devices (whether they are actually present or not)  Even the
> >> later one does not support booting from USB Card Reader or even USB
> >> flash drive.
> >>
> >>
> >> Rod