This is hard disk driver for Atari ST(E) and Falcon machines with built in IDE interface. 
It works with DOS (PC) partitioned hard disks and FAT16 BigDOS partitions
up to 2GB. Needs freeware program BigDOS (included here). BigDOS must be
run from AUTO folder, while driver itself can be started from desktop too (or from
AUTO folder). For Falcon BIGDOS-F is required (not included here).
Load this driver after Hddriver in case of need for multiple drivers.
Partitions in position on drive up to 128GB are accessible. More can not
because of BigDOS limitations.

Data transfer speed is not big because of required High/Low byte swap
 (different CPU architectures), and is about 350KB/sec. On Falcon about 1400KB/sec.
In version 4 blitter is used to enhance speed. Byte-swap blitter code is made by Shrimp.
So, on machines with blitter (Mega ST, STE) transfer speed is about 710KB/sec.
On Falcon blitter is not used, since CPU is faster.

For more speed with PC (DOS) partitined disks different interface or cable is required. Whether twisted IDE cable - what is actually hardware High/Low swap, or CATA interface (not available yet). Both need special drivers.

TWIDP_3.PRG is special driver for twisted IDE cable, where bits 0-7 and 8-15 are swapped. Then no software high-low byte swap is required, and read speed goes up to 1500KB/sec when machine has blitter, otherwise speed is about 1350KB/sec.

Option at bottom: "Press key D..X  to swap it with part. C." - it allows user to easy use different (desktop) configurations by setting different partitions as C by driver installation. D..X - X here is last available partition letter. Original partition C will be that what key is pressed, and original X will become C. If executing driver from AUTO folder then desktop and accessories will load from so choosen partition (which will be C).

P. Putnik, Aug. 2007

