99-232r0 - SAM-2 Tasks and Work

Ralph Weber ralphoweber at CompuServe.COM
Sat Aug 21 06:15:17 PDT 1999


* From the T10 Reflector (t10 at t10.org), posted by:
* Ralph Weber <ralphoweber at compuserve.com>
*
A proposal for consideration at the September meetings has
been placed on the T10 FTP site as:

< ftp://ftp.t10.org/t10/document.99/99-232r0.pdf >

The text of the proposal is as follows. Underline formatting has been
removed for ASCII text compatibility.  See the PDF for a fully
formatted presentation of the proposal.

Doc:  T10/99-232r0
Date: 21 August 1999
To:   T10 Technical Committee
From: Ralph Weber, LSI Logic Alternate Member of T10
Subj: SAM-2 Tasks and Work

During the July General SCSI Working Group meeting I reviewed a
proposal that included changes to the Task object model definition to
clarify that work to be done by the logical unit is a component of
the Task definition.  I was asked to modify that to an
'identification of the work to be done by the logical unit', since
the work itself is what the logical unit does.  The result is this
proposal.

The problem concerns the definition of a Task.  The glossary
definition of a Task (3.1.96) is, "An object within the logical unit
representing the work associated with a command or group of linked
commands."  Yet the architecture model description of a Task (4.9)
says nothing about work to be done by the logical unit being a
constituent of a Task.  This seems like a serious oversight and it
should be corrected by modifying the first few sentences in 4.9 as
follows:

Old text:

    The Task object represents either a Tagged Task or an Untagged
    Task without regard for the tagged or untagged nature of the
    Task.  A Tagged Task is composed of a Tagged Task Identifier (see
    4.9.2) and a Task Attribute (see 7.6).  An Untagged Task is
    composed of a Untagged Task Identifier (see 4.9.2) and implicitly
    a SIMPLE task attribute (see 7.6).  For convenience, Task
    Identifier (see 4.9.2) refers to either a Tagged Task Identifier
    or an Untagged Task Identifier without regard for the tagged or
    untagged nature of the task.

New text:

    The Task object represents either a Tagged Task or an Untagged
    Task without regard for the tagged or untagged nature of the
    Task.  The composition of a Task includes an identification of
    the work to be performed by the logical unit in response to a
    command or group of linked commands.  A Tagged Task is composed
    of an identification of the work to be performed by the logical
    unit, a Tagged Task Identifier (see 4.9.2) and a Task Attribute
    (see 7.6).  An Untagged Task is composed of an identification of
    the work to be performed by the logical unit, a Untagged Task
    Identifier (see 4.9.2) and implicitly a SIMPLE task attribute
    (see 7.6).  For convenience, Task Identifier (see 4.9.2) refers
    to either a Tagged Task Identifier or an Untagged Task Identifier
    without regard for the tagged or untagged nature of the task.




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