IDE-SD adapter question

Maciej W. Rozycki macro at
Tue Jun 30 17:27:26 CDT 2020


> Jonas, I am using an SD card, not CF because I need to move files from a 
> laptop to this computer using the SD. Having said that, I suspect 
> everything you said is still true. I don't have access to any linux. But 
> do you think I could make a 300MB partition (for example) on the SD card 
> and use that? I only have windows 7 or 10 machines available to me 
> (other than some PDP machines!)  I don't need very much space. I would 
> like to run windows 95 and two or three other programs.

 It didn't strike me why you needed to use SD rather than CF.

 As my memory has certainly already faded to some extent in this area I 
did a little investigation, and with some reminders I came across I need 
to mention the requirement to make the CHS geometry recorded in the MBR
partition table match one reported by the PC BIOS (as entered in the setup 
program) and the device itself.

 The ATA protocol provides for CHS geometry modification with one of the 
optional commands that the PC BIOS or other software may use for one 
reason or another, but the adapter may not necessarily support it, so one 
used with the PC BIOS of your intended device does need to match one used 
with the firmware.

 To make sure this doesn't get broken somewhere on the way you may want to 
start from scratch and erase the partition table on the SD card.  I can't 
provide you advice other than with Linux as to how to do that, now that 
UEFI is in picture.

 Once that has been done you need to establish the CHS geometry the 
adapter will use with your SD card.  You can use a detection program as I 
noted previously, however a 2GB unit is surely above the 528MB limit, so 
you can guess 1024/16/63 will be right as that is the maximum of the 
intersection of the ATA and PC BIOS CHS geometry limits and the adapter 
ought to handle it if it does the CHS stuff at all.  So use that with your 
intended computer's PC BIOS setup.

 Then boot the machine from a floppy or another device, with the SD and 
the adapter wired, and use whatever tools the OS has to partition the SD.  
Install the MBR as required.  E.g. with DOS this will be `fdisk /mbr', and 
the same command with no arguments to make the partition table.

 If you can use a Linux machine, then I can help setting up the SD card 

 I have come across: <>, where 
people report success with hardware as old as 80386, whose PC BIOS surely 
had no idea about LBA, and there haven't been that many ATA-SD adapter 
chip designs made, so chances are yours will work too with sufficient 
care, and the warning as to the use of LBA may have simply come from the 
difficulty to set up SD medium for CHS operation correctly.

 HTH, and good luck!


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