4 ms·
What about the `seek` argument which skips over some blocks at the beginning but still allocates them (unix "holes")? Also note that there are still unix syste
by knz42 10y ago
What about the `seek` argument which skips over some blocks at the beginning but still allocates them (unix "holes")?
Also note that there are still unix systems out there which do not support byte-level granularity of access to block devices. On those devices you must actually use a buffer of exactly the size of the blocks on the device. Heck, linux was like this until at least v2.
- AdamJacobMuller 10y agoAlso keep in mind that specifying the block size can be important, especially for efficiently reading data. standard shell tools don't just "figure it out" automatically. They guess, and sometimes those assumptions can be incorrect resulting in lower (orders of magnitude) performance.
- angry_octet 10y agoVery useful when dealing with raid (make the blocks stripe sized) or tape (512 byte) or esoteric devices. An essential tool for low level repair, like when you can guess the partition table values but there is no partition table anymore.