IDE-SD adapter question

Maciej W. Rozycki macro at
Fri Jun 26 20:59:18 CDT 2020

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 

 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.


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