We had same problem. Very often 84 errors and after that unload error.
We are using SGT Viper 200 drives. Problems disappear after FW upgrade to
v1414. 

|f you are using Solaris8 you can also upgrade Solaris st driver to 1.209.


Vlastimil Pokorny
UNIX Administrator
OSKAR, Cesky Mobil a.s.
Vinohradska 167, 100 00 Praha 10 
Telephone: +420 2 7117 1076
Mobil:        +420 0608 011 345
Email: vlastimil.pokorny AT oskarmobil DOT cz


>Hi All
>
>I have 2 Seagate Ultranium LTO and 6 Quantum DLT Drives installed in a 
>StorageTek L700 library. This is running in a Solaris 8 environment with 
>the latest os patches. Since installing the LTO drives I had error 84 
>"media write error" everytime I do a backup. I discovered a problem in 
>my st.conf file specifiying "xxx" instead of "XXX". This was changed but 
>I had the same problem. Someone suggested that I format the media as the 
>header could be corrupted. I have done this on media that I have 
>selected from different batches (just to put that problem to rest) but 
>still have problems. e.g. I did a multiple stream backup and got error 
>84. The amount of data written to tape was 5893240. I tried the backup 
>again using another media. This time it also failed with an error 84 
>after writing 9230656. I took mutiple streams off and tried again using 
>a different tape. This time it wrote 9627776 and also failed with error 
>84. My final attempt also failed with error 84 without writing anything 
>to tape. After failing the drive will not unload and will go into "DOWN" 
>state.
>
>Any input regarding this problem will be appreciated.
>
>Thanx.
>Bertie Booysens=20
>Software Engineer=20
>Tel: +27 11 6952507=20
>Mobile +27 82 4921410=20