On 09/28/2017 07:34 AM, Al Kossow via cctalk wrote: > Most drives 40mb and up are closed-loop with dedicated > servo surfaces and many have servos that don't work any more. > > Maxtor and Atasi are early examples of embedded servo drives. > You can tell if a drive is embedded or dedicated by the number > of heads, odd if dedicated, even if embedded.
For a lot of larger IDE drives, the "geometry" shown on the drive label (if it's shown) is a convenient fiction. Drives have used schemes such as zone recording for many years, but software expects the same number of sectors per track on a drive. And even the sector size on recent drives is fictitious. Larger drives use 4K sectors but "translate" them to the 512 byte standard. "Low level format" is pretty much a relic of the old non-servo MFM drives. I recall that early Maxtor IDE drives implemented a LLF operation, which would essentially render the drive unusable. Heck, there wasn't a lot of agreement on the IDE interface initially, so, for instance some Maxtor drives would report the total number of sectors on a drive with the capacity words swapped. Things have come a long way. --Chuck
