Although there is still a big difference between floppies and CKD hard disks – on IBM standard floppies, the sector size has to be a power of 2, minimum 128; on CKD hard disks, the sector size can be anything – 80 byte sectors, 300 byte sectors, whatever one wishes. On z/OS, several file formats require a 3120 byte block (=sector) size. Under CMS, the standard sector size is 800 bytes.
Hard disks (as opposed to floppies) commonly support non-power of 2 sector sizes, of 520 bytes or 528 bytes – for RAID systems which need to store additional metadata with each 512 byte sector. And with newer 4096 byte sector support, one sometimes finds support for 4104, 4160, and 4224 byte sectors. But, that's still not like CKD, in that most hard disks only support a fixed set of sector sizes (512 or 4096 base size plus some bytes of per-sector metadata), not arbitrary sector sizes like CKD does.
Although there is still a big difference between floppies and CKD hard disks – on IBM standard floppies, the sector size has to be a power of 2, minimum 128; on CKD hard disks, the sector size can be anything – 80 byte sectors, 300 byte sectors, whatever one wishes. On z/OS, several file formats require a 3120 byte block (=sector) size. Under CMS, the standard sector size is 800 bytes.
Hard disks (as opposed to floppies) commonly support non-power of 2 sector sizes, of 520 bytes or 528 bytes – for RAID systems which need to store additional metadata with each 512 byte sector. And with newer 4096 byte sector support, one sometimes finds support for 4104, 4160, and 4224 byte sectors. But, that's still not like CKD, in that most hard disks only support a fixed set of sector sizes (512 or 4096 base size plus some bytes of per-sector metadata), not arbitrary sector sizes like CKD does.