Yes, the scsi card readers are hotswappable on all slots,  i recommend  leaving the boot drive in the cf slot,and then use the pcmcia adapter as the swappable slot.

If you don't want the machine to boot off it,either set the partitions as non bootable or set the boot priority different than the boot drive in Hdtoolbox.

You can do many things with them. You can have 5 separate boot drives,use other slots for backups,put macos/pctask on seperate cards so no chance of corrupting sys partitions.boot multiple os's off seperate cards which is available in the early boot menu etc. by staggering the boot priority in the partitions,you can select them in early boot menu and still have the main card boot the os.

I just received some PCD=47B card readers in that are 4 slot and do not use luns. they take up 3 scsi id numbers and although slower than the pcd-50b,are very useful for some picky music samplers as well as older amiga scsi controllers that cannot use SCSI LUNS properly. It gives a good way to go solid state.
The PCD-47B will allow booting off a card in the cf/SM slots directly without the pcmcia adapter on machines that cannot use luns.


Mech

OK, so I finally got around to testing this.  Here are the scenarios.  With the OS CF plugged into the CF slot, and a non-bootable CF plugged into pcmcia slot with adapter, tries to boot from non-bootable, and stops and I get the insert bootable disk screen.  With OS CF in pcmcia, and non-bootable CF in CF slot.  Boots immediately from pcmcia OS CF, and never sees the non-bootable.  Booting with OS CF in CF slot, and non-bootable not plugged in, then plugging non-bootable into pcmcia slot with adapter after bootup:  I go into "mounter" and mount the non-bootable, it mounts successfully, and mounter shows it up as DH3, which is correct.  Never shows up on desktop, and if I go into shell and try to change to DH3:, it says insert disk into volume DH3:.  The non-bootable is formatted, and contains files.  Any suggestions.

Thanks,
Jeff

Amiga formatted with SFS

seems to me (been a long time since I have played with a new scsi device) you need to use scsi prefs and set up the device as non bootable

Have been trying to get mine to work with just the cf card, but wont boot. Only had luck so far with the adapter.
Have to tried the post on eab about setting switch 4 to on but still no luck.
Will have another go once my sick 500 is back on it's feet :-( Waiting for parts is painful just happy I could find parts :-)

I predicted the time it takes to scan LUNs would slow down booting but I didn't expect 30 sec. or more! It looks like the PCD-47B is the best all around choice for now.

I have two of these, one in my 3000T and one in my A2000. Haven't used the A3000 in a while but in the A2000 it is definitely not 30sec to start booting with just the CF card, I would say more like 10 sec, if that

It is connected to a GVP 030

Well, I don't have the GVP, (I wish I did)  I have the A2091.  If I use the CF card alone, in the PCMCIA adapter, prolly 10 seconds or so to boot.  BUT, if you use the CF card in the CF card slot, on my reader, with LUNs enabled, it takes about 30 seconds.  I don't know anything about the GVP, other than it is a better card than my A2091.