This is the smallest unit of storage in a craff file. Larger values compress better, but will waste more space if only part of the block is present. A block size of at least 4k is recommended.
This is the smallest unit of granularity in a craff file. Smaller values allow more fine-grained control of what data is present, but uses more space. For disk dumps, the sector size is useful (often 512 bytes); for memory dumps, use the page size (such as 4k or 8k).