The Berkeley Fast Filesystem (and Linux Ext2fs) use the idea of block groups. Describe
what this idea is and what improvements block groups have over the simple filesystem layout
of the System V file system (s5fs).
Answer:
-The System V file system contained four blocks – the boot block, super block, inode array and data blocks. This was inefficient, because seek times would be massive – inodes are at the start of the disk and the actual data could be anywhere from the start to the end! There was also only a single super block (block containing attributes of the entire filesystem). If this was corrupted, it's bye-bye file system.
-The Berkeley Fast Filesystem (and ext2) extended the System V filesystem by creating block groups – all equally sized and each somewhat replicating the System V structure (aside from boot block). The inode array was split into group descriptors, data block bitmap, inode bitmap and inode table. This solves the major problems with s5fs, as proximity of inode tables and data blocks is spatial localityfriendly, and you can no longer corrupt the entire filesystem by way of superblock
-The Berkeley Fast Filesystem (and ext2) extended the System V filesystem by creating block groups – all equally sized and each somewhat replicating the System V structure (aside from boot block). The inode array was split into group descriptors, data block bitmap, inode bitmap and inode table. This solves the major problems with s5fs, as proximity of inode tables and data blocks is spatial localityfriendly, and you can no longer corrupt the entire filesystem by way of superblock
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