I’m working on undertsanding deep the alignment issues.
I understand that if you have a RAID array or a RAID controller using 64KB chunks, which is default for the majority of them, you will have an alignement issue because of the “missing” sector, and it will have to r/m/w two chunks to access data spanned over two chunks.
But what about a simple 512B sector disk (not talking about AF disks) in a simple computer without RAID ? These disk have cache. Sectors on these disks are 512 bytes. Do the physical I/O operations size 512 bytes ? If so, why would alignement be an issue ?
If not… what is the damn size ? I’ve googled for quite a while now, and I can’t find an answer… I guess the disk manufacturer are putting data in the disk cache, and then, write data to the disk in chunk, and I think it would be stupid in that case to use 512 bytes operations…. But where can I find a reference about this ?
Any help welcome.
