I have an old hard drive and would like to try to read the data from it. The hard drive is IDE, but it is the old version of IDE, called XTA and it is only 8 bits wide (compared to "normal", 16bit IDE). It is also incompatible with the modern version. 8 bit controllers sometimes show up on ebay, but they are very expensive.
So, I decided to try to create an adapter from parallel (a PC is easier to program than a MCU, for me anyway) port to 8 bit IDE. For that I need specifications (timings, registers, commands), but I cannot find them anywhere. googling for XT-IDE finds lots of pages about a reverse project – a modern IDE controller that can be used in a 8bit ISA slot (on old PCs), but I want to connect an old hard drive to a newer PC. Wikipedia says that the registers have different meanings on XTA than IDE.
Can anybody share the specifications, or at least tell me where to find it?
Best Answer
From googling XTA I found the wikipedia page, which mentions XT-IDE.
The wikipedia page mentions the ST351 A/X as being a 40MB XTA drive.
Googling "ST351A/X xta programming model" led to a PDF (3rd hit, as of this writing) about the Amstrad PCW.
Why do you care about the Amstrad PCW? B/c it used a ST351 A/X in "XT mode", and said PDF contains references to where the registers lived in the XT: ports 0320h-0323h.
Now you still need to track down how ports 0x320 to 0x323 worked in an XT, but that's closer than you were.