More Streaming device questions

Burn Alting burn at goldweb.com.au
Wed Aug 25 15:53:39 PDT 2004


* From the T10 Reflector (t10 at t10.org), posted by:
* Burn Alting <burn at goldweb.com.au>
*
Can one of the SSC-3 guru's comment.

Is this a (perverse) case of the last paragraph on page 64 of T10/1611-D
Revision 01b (12 Aug 2004)? The initiator has set the logical block size
to zero and has issued a read with the fixed bit set. Is it a case of an
incorrect-length logical block attempting to be read?

Burn


On Thu, 2004-08-26 at 03:01, Tim Jones wrote:
> * From the T10 Reflector (t10 at t10.org), posted by:
> * Tim Jones <tjmac at tolisgroup.com>
> *
> I suspect that this should cause an ILI since the fixed bit changes the 
> meaning of the transfer length field (1 = Blocks, 0 = Bytes).  But, 
> since the tape drivers have to actually control the writing (rather 
> than a user app - disclaimer: on Unix systems), the driver should be 
> aware of the state of the fixed condition and modify its CDB 
> accordingly.
> 
> Tim
> --
> Tim Jones					tjmac at tolisgroup.com
> 
> On Aug 25, 2004, at 3:35 AM, Burn Alting wrote:
> 
> > * From the T10 Reflector (t10 at t10.org), posted by:
> > * Burn Alting <burn at goldweb.com.au>
> > *
> > Yet more questions.
> >
> > When I start my tape target, I set the logical block size to a default
> > value.
> >
> > For my block limits, I set my minimum block length to 512 and my 
> > maximum
> > to some large multiple of 512 bytes and since I want all IO in 512-byte
> > quantities, I set the granularity field to be 9 (ie 2^9 = 512).
> >
> > If I want to perform IO in variable block mode, am I required to first
> > set the logical block size (via a Mode Select changing the Block Length
> > field in the Mode Parameter Block Descriptor) to zero and then issue my
> > Read or Write commands with the fixed bit set to zero and the transfer
> > length to be the number of bytes I want to transfer?
> >
> > If this is the case, ie I have set the logical block size to 0, what
> > happens if a read or write command has it's fixed bit set to 1?
> >
> > Regards and thanks to all those who have been replying to my questions.
> >
> > Burn
> >
> > *
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> >
> *
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