> >Here's the output from tapetype.
> 
> Here is the clue that counts, your install is old, its been named 
> amtapetype for about a year now and now has facilities to detect the 
> drives compression status.  And I'd suspect, from the results you are 
> getting that the drives own hardware compressor is on, and that the 
> data from /dev/urandom is growing quite a bit in the hardware 
> compressor.

You are correct. I'm running Amanda 2.4.3.

However! ;]

I compiled 2.4.4p1 specifically for the _newest_ tapetype (now called
amtapetype) because I thought my results were wrong! Ha! ;] That new
amtapetype stopped at 27G as well.

Please note there was a dramatic change in the output for
(am)tapetype, including the weird new estimate stuff and compression
detection. The 2.4.3 tapetype doesn't do that. 
 
Lastly, here's the output from 'mt status'.

SCSI 2 tape drive:
File number=0, block number=0, partition=0.
Tape block size 0 bytes. Density code 0x1b (DLT 35GB).
Soft error count since last status=0
General status bits on (41010000):
 BOT ONLINE IM_REP_EN

It's got the right density code, and I've repeatedly run 'mt
compression off'. I still don't understand why I can't get more than 27G.

> >Writing 128 Mbyte   compresseable data:  28 sec
> >Writing 128 Mbyte uncompresseable data:  28 sec
> >Estimated time to write 2 * 1024 Mbyte: 448 sec = 0 h 7 min
> >wrote 860664 32Kb blocks in 2632 files in 24789 seconds (short
> > write) wrote 855261 32Kb blocks in 5247 files in 33707 seconds
> > (short write) define tapetype unknown-tapetype {
> >    comment "just produced by tapetype prog (hardware compression
> >off)"
> >    length 27065 mbytes
> >    filemark 66 kbytes
> >    speed 961 kps
> >}

Russell