IDE-SD adapter question

W2HX w2hx at
Fri Jun 26 19:16:00 CDT 2020

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?

Should I consider trying to partition the SD card into a 500MB partition?


From: Richard Cini <rich.cini at>
Sent: Friday, June 26, 2020 6:08 PM
To: W2HX <w2hx at>; General Discussion: On-Topic Posts <cctech at>
Subject: Re: IDE-SD adapter question

Off hand, I wonder if the 486 doesn't support logical block addressing in the BIOS (or its not enabled). Modern machines (and those of a Windows 95 vintage) do not use CHS addressing (cylinder, head, sector) any longer.

SD cards usually don't return Sector errors because of the dynamic remapping the firmware does.


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From: cctech <cctech-bounces at<mailto:cctech-bounces at>> on behalf of W2HX via cctech <cctech at<mailto:cctech at>>
Sent: Friday, June 26, 2020 5:39:57 PM
To: cctech at<mailto:cctech at> <cctech at<mailto:cctech at>>
Subject: IDE-SD adapter question

Hi all,

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...

In general it seems to mostly be working. I can see a directory listing of several thousands files located on a 2GB SD card from yesteryear. The SD card was new when I installed it (has been in my possession for years).

However, I do get errors "sector not found" and if I A)bort I get INT 24 error.  I am trying to get windows 95 installed and this is certainly preventing that.

In the BIOS settings I have the hard drive set as "USER" and these parameters:
CY:[1024] HD:[16] ST:[63] LZ:[1024] WP:[0]
These were the parameters in use while I was still using the actual hard drive.

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?
Question 2: The BIOS has an option to format the hard drive. Should I format the SD card using this facility?

I did not explicitly put a filesystem on that SD card. I placed it in a windows 7 machine, it was recognized, and I began copying files to it. I then place the SD card into the 486 machine where I saw the sector not found errors.

Any advice how to proceed?

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