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[ts-7000] Re: Creation of a 7800 bootable SD card

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Subject: [ts-7000] Re: Creation of a 7800 bootable SD card
From: "phrasky" <>
Date: Wed, 09 Jan 2008 18:11:01 -0000
Hi Michael,

so the partitions 1,2,3 have to be 4MB at all times? 

Would it be possible to create own MBR and so for example have only 
three patitions, with kernel, init ramdisk and rootfs, with any size 
split?

Best regards,

Petr

--- In  "John Shaffer, PhD" <> 
wrote:
>
> Just one more comment since it refutes my earlier 
theory....somewhat. 
> And I promise to shut-up. :-)
> 
> Now that I have the 7800 board working, I put an SD card in and 
used the
> 7800 fdisk command to create partitions on an SD card.  After 
creating
> the partitions, "p" reports them with a block count of 4096!  I 
used the
> "+4M" as the entry to the "last cylinder" request.
> 
> Clearly I do not understand everything that's going on but it 
seems that
> maybe the software issue Mike suggested is more of the culprit now
> (apologies Mike!).  I know very little of how fdisk works or the 
details
> of an MBR structure so I presume now that the MBR contains info on 
what
> a blocksize is as well as all the other info.
> 
> In any event, just thought I'd share this since it might do 
someone some
> good.
> 
> John Shaffer
> Lakota Innovations, LLC
> 
> 
> Michael Schmidt wrote:
> >
> >
> > On Mon, January 7, 2008 10:14 am, jhslakota wrote:
> > > Hello all, I'm a newbie on this group and have a question. 
Actually I
> > > solved a problem I had and some of the posts have helped but 
ultimately
> > > I did something NOT suggested and solved the problem. Posting 
here in
> > > the hope that my description and any discussion will help 
others. [:)]
> > >
> > > Short version:
> > > The root partition used in the 7800.mbr is only 4096 blocks 
long (2MB)
> > > but the kernel image is 3.5MB. This caused me many problems 
before
> > > realizing this mismatch.
> >
> > I suspect what is happening here is that there are some software
> > disagreements about how big a "block" is. That partition is 
supposed to
> > be 4MB in size, which would be 4096 * 1k blocks. In our 
production
> > process this all works fine, but there may be some differences 
between
> > your environment and ours. For instance, when we blast the flash 
on a
> > 7800 it is running from an NFS-root environment, and all the 
commands are
> > run directly on the 7800.
> >
> > For example, from the 7800 on my desk I see the following:
> > /mnt/host # fdisk /dev/tssdcardb
> >
> > Command (m for help): p
> >
> > Disk /dev/tssdcardb: 507 MB, 507379712 bytes
> > 255 heads, 63 sectors/track, 61 cylinders
> > Units = cylinders of 16065 * 512 = 8225280 bytes
> >
> > Device Boot Start End Blocks Id System
> > /dev/tssdcardb1 1 1 4096 c Win95 FAT32 (LBA)
> > Partition 1 has different physical/logical beginnings 
(non-Linux?):
> > phys=(0, 4, 13) logical=(0, 4, 5)
> > Partition 1 has different physical/logical endings:
> > phys=(17, 2, 30) logical=(0, 134, 6)
> > Partition 1 does not end on cylinder boundary
> > /dev/tssdcardb2 1 2 4096 da Unknown
> > Partition 2 has different physical/logical beginnings 
(non-Linux?):
> > phys=(17, 2, 31) logical=(0, 134, 7)
> > Partition 2 has different physical/logical endings:
> > phys=(34, 0, 48) logical=(1, 9, 8)
> > Partition 2 does not end on cylinder boundary
> > /dev/tssdcardb3 2 2 4096 da Unknown
> > Partition 3 has different physical/logical beginnings 
(non-Linux?):
> > phys=(34, 0, 49) logical=(1, 9, 9)
> > Partition 3 has different physical/logical endings:
> > phys=(50, 7, 5) logical=(1, 139, 10)
> > Partition 3 does not end on cylinder boundary
> > /dev/tssdcardb4 2 62 482944 83 Linux
> > Partition 4 has different physical/logical beginnings 
(non-Linux?):
> > phys=(50, 7, 6) logical=(1, 139, 11)
> > Partition 4 has different physical/logical endings:
> > phys=(1023, 7, 61) logical=(61, 170, 45)
> >
> > Partition 4 does not end on cylinder boundary
> >
> > Command (m for help): q
> >
> > /mnt/host # dd if=/dev/tssdcardb2 of=tmp
> > 8192+0 records in
> > 8192+0 records out
> > /mnt/host # ls -l tmp
> > -rw-r--r-- 1 root dialout 4194304 Jan 7 2008 tmp
> >
> > Manually resizing the partitions as needed is a valid solution. 
Both
> > kernel and initrd partitions are supposed to be 4MB, with the 
last
> > (rootfs) parition taking whatever remaining space is left.
> >
> > ______ Best Regards,
> > |__ __/ Michael Schmidt
> > || Software Engineer
> > ||echnologic Systems (EmbeddedARM.com)
> > || (480) 16610 East Laser Drive #10
> > |/ 837-5200 Fountain Hills, AZ 85268
> > http://oz.embeddedarm.com/~michael 
<http://oz.embeddedarm.com/%7Emichael>
> >
> >  
> 
> -- 
> ------------------------------------------------------------------------
> John H Shaffer PhD
> Managing Partner
> 507-252-8927
>   logo
>       Lakota Innovations LLC
> 2015 Valkyrie Dr NW
> Rochester, MN 55901
> 
> ------------------------------------------------------------------------
>




 
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