On Sat, 27 Jun 2020, W2HX via cctech wrote:
Could it be related to the fact that it is a 2GB SD
card and I believe
IDE controllers of that day could only address something like 500MB?
Except for a few sophisticated caching host bus adapters and ATA RAID
controllers that presented their own software interface an ATA host bus
adapter was essentially a pass-through device with an address decoder and
a bunch of tri-state logic buffers. The IDE controller was (as the name
suggested) integrated with the ATA device itself. Therefore all the
simple ISA host bus adapters for ATA devices supported even the LBA48 mode
as they did not interpret values passed through the control registers,
which resided on the ATA device (similarly ATAPI support can work, which
issues commands in the data stream rather than via the ATA command
register).
The limitation came from solely from the PC BIOS interface; once an OS
has been booted that could drive ATA devices itself you could use the
full capacity of any ATA device.
Maciej