Re: Re: Any ideas to deal with a VMBACKUP problem?

jsganino wrote:
> 
> 
> 
> So, it looks like VMBACKUP is asking about the tape drive, i.e., "Who are you?" or "What can you do?" or something like that.  The answer comes back:
> 

Actually, a standalone 'SENSE' (X'04') like this is just to clear any 
residual sense data and to clear any 'Status Pending' condition on the 
subchannel. It may also help determine if a tape is loaded or not, if it 
is at load point and/or if the mounted media is writable (although on a 
real 3420 you could only determine this *after* having attempted a write).

If the program at this point was trying to determine the device type 
("Who are you") it would issue a X'E4' (Sense ID - Not available on the 
3420 and older tape drives[1]).. And as far as "What can you do?" it 
would probably need to issue a RDC X'64' (Read Device Characteristics - 
3490 and above only).

--Ivan

[1] You can make Sense ID work on a 3420 in hercules by specifying the 
'LEGACYSENSEID ENABLE' statement in the configuration file - but the 
results can only be understood by custom programs (not stock programs) 
since no real 3420 ever supported it - and thus - wouldn't have anything 
to refer to. In some operating systems (notably MTS) - the X'E4' CCW 
command code is expected to return Unit Check + Command Reject on a 3420.