More Streaming device questions

Kevin D Butt kdbutt at us.ibm.com
Thu Aug 26 10:06:16 PDT 2004


* From the T10 Reflector (t10 at t10.org), posted by:
* Kevin D Butt <kdbutt at us.ibm.com>
*
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Burn, 

The way this is supposed to work is: 

A Block Length value of 0 indicates that only variable block transfers
are allowed. 
If the Fixed bit is set to 1, the Block Length field set to 0, and the
Transfer Length field is not 0, Check Condition status is returned with
Illegal Field in CDB (5/2400h). 

I have to admit that I don't find this in SSC-3. 

Dave, 

Do you know where this is specified?  If we have dropped it, or it is
not specified, we should add it. 

Thanks, 

Kevin D. Butt
Fibre Channel & SCSI Architect, IBM Tape Microcode, 
6TYA, 9000 S. Rita Rd., Tucson, AZ  85744
Tie-line 321; Office: 520-799-5280, Lab: 799-5751, Fax: 799-4138, Email:
kdbutt at us.ibm.com 



Burn Alting <burn at goldweb.com.au> 
Sent by: owner-t10 at t10.org 


08/25/2004 03:53 PM 

To
t10 at t10.org 

cc

Subject
Re: More Streaming device questions

	





* 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
> >
> > *
> > * For T10 Reflector information, send a message with
> > * 'info t10' (no quotes) in the message body to majordomo at t10.org
> >
> *
> * For T10 Reflector information, send a message with
> * 'info t10' (no quotes) in the message body to majordomo at t10.org
> 

*
* For T10 Reflector information, send a message with
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<br><font size=2 face="sans-serif">Burn,</font>
<br>
<br><font size=2 face="sans-serif">The way this is supposed to work is:</font>
<br>
<br><font size=2 face="sans-serif">A Block Length value of 0 indicates
that only variable block transfers are allowed.</font>
<br><font size=2 face="sans-serif">If the Fixed bit is set to 1, the Block
Length field set to 0, and the Transfer Length field is not 0, Check Condition
status is returned with Illegal Field in CDB (5/2400h).</font>
<br>
<br><font size=2 face="sans-serif">I have to admit that I don't find this
in SSC-3.</font>
<br>
<br><font size=2 face="sans-serif">Dave,</font>
<br>
<br><font size=2 face="sans-serif">Do you know where this is specified?
&nbsp;If we have dropped it, or it is not specified, we should add it.</font>
<br>
<br><font size=2 face="sans-serif">Thanks,</font>
<br><font size=2 face="sans-serif"><br>
Kevin D. Butt<br>
Fibre Channel &amp; SCSI Architect, IBM Tape Microcode, <br>
6TYA, 9000 S. Rita Rd., Tucson, AZ &nbsp;85744<br>
Tie-line 321; Office: 520-799-5280, Lab: 799-5751, Fax: 799-4138, Email:
kdbutt at us.ibm.com</font>
<br>
<br>
<br>
<table width=100%>
<tr valign=top>
<td width=40%><font size=1 face="sans-serif"><b>Burn Alting <burn at goldweb.com.au&gt;</b>
</font>
<br><font size=1 face="sans-serif">Sent by: owner-t10 at t10.org</font>
<p><font size=1 face="sans-serif">08/25/2004 03:53 PM</font>
<td width=59%>
<table width=100%>
<tr>
<td>
<div align=right><font size=1 face="sans-serif">To</font></div>
<td valign=top><font size=1 face="sans-serif">t10 at t10.org</font>
<tr>
<td>
<div align=right><font size=1 face="sans-serif">cc</font></div>
<td valign=top>
<tr>
<td>
<div align=right><font size=1 face="sans-serif">Subject</font></div>
<td valign=top><font size=1 face="sans-serif">Re: More Streaming device
questions</font></table>
<br>
<table>
<tr valign=top>
<td>
<td></table>
<br></table>
<br>
<br>
<br><font size=2><tt>* From the T10 Reflector (t10 at t10.org), posted by:<br>
* Burn Alting <burn at goldweb.com.au&gt;<br>
*<br>
Can one of the SSC-3 guru's comment.<br>
<br>
Is this a (perverse) case of the last paragraph on page 64 of T10/1611-D<br>
Revision 01b (12 Aug 2004)? The initiator has set the logical block size<br>
to zero and has issued a read with the fixed bit set. Is it a case of an<br>
incorrect-length logical block attempting to be read?<br>
<br>
Burn<br>
<br>
<br>
On Thu, 2004-08-26 at 03:01, Tim Jones wrote:<br>
> * From the T10 Reflector (t10 at t10.org), posted by:<br>
> * Tim Jones <tjmac at tolisgroup.com&gt;<br>
> *<br>
> I suspect that this should cause an ILI since the fixed bit changes
the <br>
> meaning of the transfer length field (1 = Blocks, 0 = Bytes). &nbsp;But,
<br>
> since the tape drivers have to actually control the writing (rather
<br>
> than a user app - disclaimer: on Unix systems), the driver should
be <br>
> aware of the state of the fixed condition and modify its CDB <br>
> accordingly.<br>
> <br>
> Tim<br>
> --<br>
> Tim Jones &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;
&nbsp; &nbsp; &nbsp; tjmac at tolisgroup.com<br>
> <br>
> On Aug 25, 2004, at 3:35 AM, Burn Alting wrote:<br>
> <br>
> > * From the T10 Reflector (t10 at t10.org), posted by:<br>
> > * Burn Alting <burn at goldweb.com.au&gt;<br>
> > *<br>
> > Yet more questions.<br>
> ><br>
> > When I start my tape target, I set the logical block size to
a default<br>
> > value.<br>
> ><br>
> > For my block limits, I set my minimum block length to 512 and
my <br>
> > maximum<br>
> > to some large multiple of 512 bytes and since I want all IO in
512-byte<br>
> > quantities, I set the granularity field to be 9 (ie 2^9 = 512).<br>
> ><br>
> > If I want to perform IO in variable block mode, am I required
to first<br>
> > set the logical block size (via a Mode Select changing the Block
Length<br>
> > field in the Mode Parameter Block Descriptor) to zero and then
issue my<br>
> > Read or Write commands with the fixed bit set to zero and the
transfer<br>
> > length to be the number of bytes I want to transfer?<br>
> ><br>
> > If this is the case, ie I have set the logical block size to
0, what<br>
> > happens if a read or write command has it's fixed bit set to
1?<br>
> ><br>
> > Regards and thanks to all those who have been replying to my
questions.<br>
> ><br>
> > Burn<br>
> ><br>
> > *<br>
> > * For T10 Reflector information, send a message with<br>
> > * 'info t10' (no quotes) in the message body to majordomo at t10.org<br>
> ><br>
> *<br>
> * For T10 Reflector information, send a message with<br>
> * 'info t10' (no quotes) in the message body to majordomo at t10.org<br>
> <br>
<br>
*<br>
* For T10 Reflector information, send a message with<br>
* 'info t10' (no quotes) in the message body to majordomo at t10.org<br>
</tt></font>
<br>
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