Comments on 94-081r0, Mandatory and Optional in SAM
Charles Monia, SHR3-2/W4, 237-6757, email@example.com 28-Mar-1994 1941
monia at starch.enet.dec.com
Mon Mar 28 16:40:38 PST 1994
Subject: Comments on 94-081r0, Mandatory and Optional in SAM
The following are my comments and suggestions on the proposal
for clarifying the specification of SAM requirements.
I think the proposal is a good idea and suggest, in
addition, that SAM be modified to clearly specify:
a)Whether or not the referenced item must be specified in
a standard and
b)if so, whether or not the standard shall require the item
to be implemented.
Also, SAM should be modified to define which SCSI-3 standards
apply to specific SAM entities (logical units, target devices,
My comments are preceded by ">".
>(new item) page XZ: 2.1.xx applicable standard: Standard having
>jurisdiction over the specification of the referenced item.
(new item) Page 12: 2.1.28 implemented: The referenced item from a
standard is realized in the actualization of the standard. For standards
complying with SAM, an implemented item is an item in SAM realized
within that standard. For devices complying with a standard (e.g.
products), an implemented item is an item in that standard which is
realized within that device.
>To me, "implementation" strongly connotes the physical instantiation of
>the referenced item in an SCSI-3 system or subsystem. Since SAM governs
>implementations as well as specifications (e.g., the queuing model), I'd
>like to retain this distinction by modifying the above as follows:
>(new item) Page 12: 2.1.28 implemented: The referenced item is
>physically instantiated. In SAM, 'implementation' refers to the
>instantiation of the referenced item in one or more components of an
>SCSI-3 I/O system.
>(new Item) Page XX 2.1.xxx specified: The standard delineates the
>referenced item by prescibing the manner and circumstances under which
>it shall be implemented.
>(new item)page XX 2.1.xx instantiation: The realization of an item. In
>the context of a standard, the instantiation of an item refers to its
>specification within that standard. In the context of a physical system or
>subsystem, the instantiation of an item refers to those aspects of the
>implementation that cause the specified behavior to be manifested.
(new item) Page 13: 2.1.34 item: A feature defined within a
standard. The fundamental element for claiming compliance
to a standard.
>The following modified version includes the notion that requirements and
>features have to be observable by some entity.
>(new item) Page 13: 2.1.34 item: A measurable or observable feature
>defined within a standard. A fundamental element for assessing a claim
>of compliance to a standard.
Page 13: 2.1.41 mandatory: The referenced item is required
to claim compliance with the specified standard.
>Page 13: 2.1.41 mandatory: instantiation of the referenced item is
>required to claim compliance with the specified standard.
page 13: 2.1.44 optional: The referenced item need not be implemented
to claim compliance with a standard.
>page 13: 2.1.44 optional: The referenced item need not be instantiated
>to claim compliance with a given standard. If instantiated, the
>referenced item shall comply with the standard.
(new item) page 13: 2.1.45 option set: A set of referenced items
which individually are considered to be optional. If all of the
items are implemented, then the option set is implemented.
If any item is not implemented, then the option set is not implemented.
A new section should also be created (I suggest section 2.4) as follows:
Grounds for Compliance
SAM consists of a set of items, each of which is clearly
noted as being mandatory (either explicitly or implicitly
by the use of the word "shall") or optional (either explicitly
or implicitly by the use of the word "may").
All standards claiming compliance with SAM shall implement
within the standard all mandatory SAM items. A standard
may implement optional SAM items.
All standards claiming compliance with SAM shall in turn
consist or a set of items, each of which is clearly noted
as being mandatory or optional. Optional items may be grouped
together as optional sets. Any implementation claiming
compliance with that standard shall implement all mandatory
items and may implement any optional items.
Any standard claiming compliance with SAM must provide a
facility to allow the determination of whether an implementation
of that standard implements specific optional items identified
in SAM. This determination shall typically be done during a
>I'd suggest further qualifying the requirements based on the scope of
>the standard as follows:
>"SAM consists of a set of mandatory and optional items, each of which is
>applicable to at least one of the functional areas described in clause
>1. An item is noted as mandatory (either explicitly or implicitly by the
>use of the word "shall") or optional (either explicitly or implicitly by
>the use of the word "may")."
>"A standard claiming compliance to SAM shall identify the functional
>areas with which it conforms and shall comply with all mandatory items
>defined by SAM as relevant to standards within those areas. A standard
>may also comply with optional items."
>"All standards claiming compliance with SAM shall
>consist or a set of items, each of which is clearly noted
>as being mandatory or optional. Optional items may be grouped
>together as optional sets."
>"An implementation claiming compliance with SAM shall identify the
>functional areas and standards within that area with which it complies.
>The implementation shall conform to all mandatory items in those
>standards as well as all as all mandatory items in SAM that apply
>directly to such an implementation. An implementation may also comply
>with optional items."
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