A few days ago, I spoke well of the IBM USB floppy for the Thinkpad 21. 
I fear I spoke too soon...  It works well for reading, but when I try 
to write to it I get errors like this:

sd0(umass0:1:0):  Check Condition on CDB: 0x2a 00 00 00 00 04 00 00 04 00
    SENSE KEY:  Not Ready
     ASC/ASCQ:  ASC 0x04 ASCQ 0xff

sd0(umass0:1:0):  Check Condition on CDB: 0x1e 00 00 00 00 00
    SENSE KEY:  Aborted Command
     ASC/ASCQ:  Overlapped Commands Attempted


The drive is attached as a SCSI drive:

umass0: TEAC     TEAC FD-05PUB   , rev 1.00/0.00, addr 2
umass0: using UFI over CBI-I
scsibus0 at umass0: 2 targets, 1 luns per target
scsibus0: waiting 2 seconds for devices to settle...
sd0 at scsibus0 target 1 lun 0: <TEAC, FD-05PUB, 1026> SCSI0 0/direct removable

This is in 1.5.1, but I saw similar behavior on 1.5R. 

The output shown above is when using mtools; when I tried a write after 
mounting the MSDOS file system, I got only the first error message.
(On one occasion, I tried an 'ls /mnt' after getting the error message.
This was a mistake, as the system's behavior reminded me more of Windows.
I'm not used to involuntary reboots on Unix...)

My guess is that I need an entry in the scsi quirks table, but just 
what it should be is far from obvious to me.


		--Steve Bellovin, http://www.research.att.com/~smb