Read only filesystem size issues.

[Dean Brown]

Adi,
I've been hacking at the pwl_target scripts with the intent to target
them for a specific application. In the process of doing so, I noticed a
couple of potential problems with the partition sizing calculations for
the read only fs with multiple ramdisks.

1) When calculating the size of the / filesystem, the /home and /root
directories are included. These directories are then separated out and
placed in the second partition. The size of the /home and /root
directories are not subtracted from the / filesystem. This overestimates
the size of the / filesystem by the size of the /home and /root
directories.

2) Partition sizes are calculated by using du -s -k command. This bases
file size on the cluster size of the development systems filesystem. In
my case this cluster size is 4K, while the cluster size of the flash
device is set to 1K. This also tends to overestimate the required size
of the flash device.

The result of these issues is that if your build is approaching the size
of your flash device, chances are very good that the pwl_target_load
functions will fail to load the device. In my case, an extracted 13
MByte filesystem fails to load on a 16 MByte compact flash because there
supposedly wasn't enough room.

This is no longer an issue for me as I've eliminated the separate /home
partition on the target device, but your other users may benefit from
this information.

-- 
Dean Brown
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