This item is from the Yet Another Enhanced IDE/Fast-ATA/ATA-2 FAQ, by John Wehman and Peter den Haan with numerous contributions by others. (v1.92).
The fast transfer modes (PIO modes 3 and 4, multiword DMA modes 1 and 2) are the cornerstones of Fast-ATA and EIDE. These are marketing terms contrived by disk drive manufacturers. Enhanced IDE is a Western Digital trademark; Fast-ATA is a term coined by Seagate, and endorsed by Seagate and Quantum.
EIDE consists of:
o Fast transfer modes: PIO mode 3 or better, multiword DMA mode 1 or better,
o LBA mode (explained in section 10.7),
o Four devices on the ATA interface: secondary port,
o No 504MB limit with DOS: WD Enhanced BIOS,
o tape backup and CD-ROM devices on the ATA interface: ATAPI.
Fast-ATA and Fast-ATA-2 embrace:
o PIO mode 3 (and 4 for Fast-ATA-2), multiword DMA mode 1 (and 2 for Fast-ATA-2),
o Read/Write multiple commands (also known as block mode; see Q10.6),
o LBA mode.
The difference between the two schemes is mainly in the scope of EIDE. Hardware can be tagged 'EIDE' even if only part of the EIDE feature set has been implemented, which can lead to some confusion. This FAQ will avoid the term EIDE whenever possible, discussing its component parts (ATA-2, ATAPI, etc) instead. This allows you to see exactly what 'EIDE' features you need in your specific situation.