The ST-506 connected to a computer system through a disk controller.

The disk controller could support up to four (4) 500MB hard drives.

And how do I know which cards require a disk controller?

If the drive appears likely to fail soon, the system sends notification to the disk controller.

A version with a 20-megabyte hard disk controller costs $2,295.

Early disk controllers were identified by their storage methods and data encoding.

But Bob was instead working on two disk controllers as these were not off the shelf chips quite yet.

A special "sync mark" is used to allow the disk controller to figure out where the data starts.

A disk controller could transfer data into memory with no load on the processor.

It included a hard disk controller as part of the basic configuration.