[Soekris] Net4521 and PCMCIA hard drive?

[Gordon Schumacher]

As a former employee of Integral Peripherals, I've got a few 340MB
PCMCIA (16-bit) hard drives sitting about, and I was hoping to get one
working as swap space in a net4521 (booting off a CF drive).  For some
reason, it doesn't seem to even spin up when plugged into the slot;
the back of the drive lists its power requirement as 5V at 0.5A, which
seems like it should be safe.  I'm running the Soekris on a 12V 3A
power supply, though I'm not sure what the board's supply will
actually deliver.

Can anyone think of why it's not working?  The Linux kernel recognizes
that a card is present - it just won't attach a driver to it, and the
drive won't spin up.  They work fine on a laptop, so it's not the
drive.

Thanks!