Hi, Gene Heskett wrote: > The real problem is of coarse that there has not ever been 2 identical sd > cards made, so a dd image to the end of the card A, will not ever > install that image on another supposedly identical card B or C, they are > NOT the same size except in the salespersons mind. Therefore, the image > must be constrained to a gig or so beyond the end of the used portion of > the card. And some utility is then invoked to look at the card during > the initial bootup, that re-expands the last partition to encompass the > remainder of THAT card.
You could install a bumper partition 8 at the end of the card. Whatever automat you suffer from, it would have to be extra stupid to expand partition 7 into the range of the bumper. Let's assume a minimum size of rounded up 16 billion with a "16 GB" medium. Then let's subtract a coward's reserve of 100 million bytes, and divide by the block size: ( 15.5e9 - 100e6 ) / 512 = 30078125 So if you create partition 8 starting at block 30,078,125 and reaching up to the end of the usable block range, then the image from block 0 to the end of partition 7 should be portable to any "16 GB" medium. Ideally you should delete partition 8 before copying from the original medium. So it does not confuse partition editors after the image was copied to a new medium. The GPT header and the backup GPT would have to be re-created with the new medium size. Partition 8 would have to be re-created from the same start block up to the end of the usable block range. gdisk seems to be able to do this. Start blocks for bumpers: Rounded up "8 GB" - 50 MB : 14,550,781 Rounded up "16 GB" - 100 MB : 30,078,125 Rounded up "32 GB" - 200 MB : 61,132,812 Rounded up "64 GB" - 500 MB : 123,046,875 Have a nice day :) Thomas
