I obtained a quantity of these IDE 44 pin SSDs for use in my retro computers. At first I simply used an adapter to connect to the 40 pin IDE port, but it caused all sorts of weird problems e.g. the floppy disk change line didn't work and the POST info screen shows serial ports that don't exist.
I focused on determining why it's detecting 4 serial ports that don't exist since that seemed like the easiest. I built an IDE breakout and found disconnecting neither /CS0 nor /CS1 made the above issue go away, only disconnecting /IOR stopped the problems. I then further found that each time /IOR was asserted, it pulled down at least one data line even if neither IDE chip select was asserted. Looking at this on a scope, it's clear one or more data lines are pulled down partway, clearly not normal.
This SSD works great on a couple computers I have that have proper IDE interfaces, i.e. ones with bus transceivers. The two that are having issues have a stripped down multi I/O card where the data lines go straight to the ISA bus. Nonetheless, a regular HDD works perfectly with this card. If I connect this SSD up to power, pull both chip selects high and put pull-ups on the data lines, some data lines pull down hard for 14 or 15ms when I manually assert /IOR. I thought a drive's IDE interface is supposed to stay in high-Z unless one of the chip selects are asserted? Anyone know what's going on here?