So I'm installing a 9gb Quantum Atlas 10k Ultra160 scsi drive with a 68 pin interface into my PowerMac 8500.  I have a 68 to 50 pin adapter to hook it up.  So I get it all together, boot up 7.6.1, launch Lido and there it is.  I partition it into several 2gb or less partitions (I'm planning on installing some of these into some older macs too).  It formats fine, and I run some tests, which also go fine.  But then I shut down, and upon restarting, none of those partitions are there, Lido no longer even sees the drive, nor do several other formatters (hdsc patched, anubis, a couple of others).  No sign that it's even on the scsi bus.

What happened?

I have several of these drives, and the same thing has happened on two of them.  I don't dare fool around and possibly kill any more of them.  Any ideas?