IDE-SD adapter question

[Peter Corlett]

On Fri, Jun 26, 2020 at 09:39:57PM +0000, W2HX via cctech wrote:
> Thanks for previous help on this project. I am working on an old 486 computer
> and I have replaced a 40 pin IDE hard drive with this SD adapter...
> https://www.amazon.com/gp/product/B07G29TZPS/ref=ppx_yo_dt_b_asin_title_o01_s00?ie=UTF8&psc=1
[...]
> Question 1: Now that I am using an SD card instead of an IDE drive, what, if
> anything, should I be doing with these BIOS parameters?

The description of that adaptor says "Attention: Some of the mother board
required to enable LBA mode and disable DMA transfer mode." This suggests to me
that it does not support CHS addressing, and as the Engrish says, you need to
use LBA mode instead.

If your motherboard only supports CHS, you're likely to have a hard time
getting many of these cheap adaptors to work with it. You might have better
luck with Compact Flash, since the adaptors are passive and the CHS/LBA support
(or lack thereof) is a function of the card, which is liable to be of better
quality.