[nanobsd] Calculation of new flash image size

[Krassimir Slavchev]

What about diskinfo?
I always use output from diskinfo -v without any problems.


Warner Losh wrote:
> From: Sean Bruno <sbruno at miralink.com>
> Subject: [nanobsd] Calculation of new flash image size
> Date: Mon, 21 May 2007 17:06:23 -0700
>
>   
>> If the manufacturer doesn't provide me with the specific values for 
>> NANO_SECTS, NANO_HEADS and NANO_MEDIASIZE, I assume that I would be able 
>> to use the output of fdisk to calculate it for me:
>>
>> fmybox# fdisk /dev/ad0
>> ******* Working on device /dev/ad0 *******
>> parameters extracted from in-core disklabel are:
>> cylinders=993 heads=16 sectors/track=63 (1008 blks/cyl)
>>
>> parameters to be used for BIOS calculations are:
>> cylinders=993 heads=16 sectors/track=63 (1008 blks/cyl)
>>
>>
>> So in this case, NANO_SECTS=63, NANO_HEADS=16 and NANO_MEDIASIZE=(993 * 
>> 16 * 63)=1000944?
>>
>> I added the following to Flashdevices.sub:
>>
>>                 dom512m)
>>                         # Source: sbruno at miralink.com
>>                         NANO_MEDIASIZE=`expr 512483328 / 512`
>>                         NANO_HEADS=16
>>                         NANO_SECTS=63
>>                         ;;
>>     
>
> The flashdevices.sub database is lame.  It is a misfeature to require
> it.
>
>   
>> If I do this for my new Transcend module, the system won't boot properly 
>> and freezes on the BTX boot loader startup.
>>
>> What am I doing wrong here?
>>     
>
> There's a fundamental flaw in nanobsd.  That is that it requires one
> to know the geometry of the target device.  fdisk won't tell you this
> when you are using a scsi card reader, so you can't find it out
> automatically.  This is because the scsi layer uses a fake geometry
> here (I can't recall if it is FreeBSD software, or the card reader).
> Nanobsd is supposed to use 'packet mode' so that geometry doesn't
> matter.  You should make sure that the CF/disk created is in packet
> mode.
>
> If you have a card that you've re-fdisked since you bought it, dd
> about 30k of zeros to the front of it from /dev/zero.  Then insert it
> into a camera that can do the formatting of flash cards.  Put that
> back into your freebsd box and run fdisk again and see what the
> partitions look like.
>
> You'll see something that looks like:
>
> fdisk da0
>
> ******* Working on device /dev/da0 *******
> parameters extracted from in-core disklabel are:
> cylinders=CCC heads=HHH sectors/track=SSS (SSS * HHH blks/cyl)
>
> Figures below won't work with BIOS for partitions not in cyl 1
> parameters to be used for BIOS calculations are:
> cylinders=CCC heads=HHH sectors/track=SSS (SSS * HHH blks/cyl)
>
> Media sector size is 512
> Warning: BIOS sector numbering starts with sector 1
> Information from DOS bootblock is:
> The data for partition 1 is:
> sysid 6 (0x6),(Primary 'big' DOS (>= 32MB)
>     start SSS, size XXX (YYY Meg), flag 80 (active)
>         beg: cyl 0/ head 1/ sector 1;
>         end: cyl CCC/ head HHH/ sector SSS
> The data for partition 2 is:
> <UNUSED>
> The data for partition 3 is:
> <UNUSED>
> The data for partition 4 is:
> <UNUSED>
>
> CCC, HHH and SSS are the numbers you need.
>
> Also, you can put this card in your target device and look at the BIOS
> in that target device.  It will tell you what it thinks it is.
>
> Warner
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