Basic File System question...
OK, so I have been studying the I-node based file systems recently (largely the Minix file system, and the Ext2 file system); I understand that the partition is divided into block groups, and all that jazz, but what I don't understand is this: is there a limit, like some parameter, that constrains the maximum number of block groups?
I mean, suppose we had an ideal computer with 1 Yottabyte of space (or 2 to the 80th bytes). If we had the block size be 2^12 bytes (4 KB), there are 2^68 blocks. Here's the problem: an unsigned long long is capable of a maximum value of 2^64. Wouldn't there be 2^68 - 2^64 blocks that won't be accessible? Granted that this is so large that it wouldn't matter, but it wouldn't be that efficient (well, 2^64 over 2^68 = 0.000244141 = 0.024%, which is pretty lousy).
Am I approaching this the wrong way, or does the number of block groups not matter?
