Running OpenBSD off of compactflash

[Mike Shaw <mshaw_(_at_)_wwisp_(_dot_)_com>]

Several folks have asked me about compact flash, since it was in my /etc/ 
question.  Here's the small knowledge base I've developed so far.  If 
anyone has additional or contrary info, feel free to jump in.

* I haven't tried the USB adapters, but I've heard mixed reviews on them 
for any *nix.  I haven't heard of anyone managing to boot from them.

* The IDE CF adapters are the only ones I've used and they work 
great.  They can be picked up for almost nothing on ebay.  Usually 10-20 
bucks.  The flash is pretty much self contained, and the IDE adapters are 
little more than pin adapters.

* You don't want to run anything that will substantially 'write' the card 
more than a few times a day.  The cards will only take 100k-1million 
writes, which sounds like alot but your typical windows box can supposedly 
swap a card to death in a couple of months.  So bulk up on ram and run 
without swap.  Log off box or set up a ramdisk/dump routine--you get the 
picture.

* Stick with Sandisk flash.  You may get others to work but it can be a 
wildcard situation.  The manufacturers don't always stick to the specs, and 
while this doesn't seem to bother your typical consumer app (cameras, PDAs, 
etc) it can really cause problems when your OS is trying to pretend it's a 
disk, particularly with geometry.  I had several no-fun issues until I 
sucked it up and got Sandisk.

* ...really spooky when your box boots up without that little HD clicking 
sound.

* The cards work in PIO mode, which is supposedly much harder on the 
processor.  Another reason to log off box, etc.

I haven't tried the distribution, but there's alot of information to be 
found by looking at the emBSD project page and mailing list archives. 
(www.embsd.org).  They also have a lil' box that runs entirely off of flash 
which I'll probably try out when I get my personal distro finished.

-Mike