exabyte to exabyte copy -- How?

[The Grey Wolf]

/* <GPLAN.91Apr5184957 at sun9.aer.com> by gplan at sun9.aer.com (George Planansky)
 * I need a way to make copies of our exabyte dump tapes, a couple of
 * times a week.  These have ten or so dump files on them.
 * 2. Is there in fact a way to run exabyte drives to make copies directly:
 * 
 *    exabyte tape drive a  ---> exabyte tape drive b
 * 
 * 3. If there is a reasonable way to make duplicates of these exabyte
 * tapes, I would appreciate hearing of it.

Have you considered something like:

dd if=/dev/xbt0 of=/dev/xbt1 ibs=128k obs=128k

I used to do that with *other* tapes :-) (insert standard exabyte-ignorant
disclaimer).  It ought to work pretty well, though, especially if the drive
can read/write at a fairly good clip (in which case 128k may not be the top
limit on performance).

Question:  Is the Exabyte SCSI-only, or has anyone made a decent DMA
implementation (I am (possibly erroneously) under the impression that
SCSI does not do DMA))?

 * 
 * Thanks.
 * --
 * George Planansky                       
 * Atmospheric & Environmental Research        
 * 840 Memorial Drive, Cambridge, MA 02139     
 * gplanansky at aer.com   (617) 547-6207 fax: 661-6479