Project Proposal for SCSI-4 Parallel Interface - 3 (SPI-3) Physical & Protocol Layers

[Larry Lamers]

* From the T10 (formerly SCSI) Reflector (t10 at symbios.com), posted by:
* Larry Lamers <ljlamers at corp.adaptec.com>
*
T10/97-262r0 Project Proposal For a New NCITS Standard
SCSI-4 Parallel Interface - 3 (SPI-3) Physical & Protocol Layers
1.   IDENTIFICATION OF PROPOSED PROJECT
1.1  TITLE:  SCSI-4 Parallel Interconnect - 3 (SPI-3)t
1.2  PROPOSER:  T10.
1.3  DATE SUBMITTED:  November 11, 1997
1.4  PROJECT TYPE: D - Development of a standard within an NCITS TC.

2.   JUSTIFICATION OF PROPOSED STANDARD

2.1  NEEDS:

Project Proposal for SCSI-4 Parallel Interface - 3 (SPI-3), a
second generation low-voltage differential (LVD-2) technology,
that will allow a dual-channel host adapter to attain greater
than 5 Gbits per second data rate, effectively quintupling the
data rate of current serial technology.  This LVD-2 technology
will allow peripherals to meet the data I/O needs of the next
generation 64-bit processors being delivered by the end of the
millenium.

In addition to improving the fundamental data rate to 80 mega-
transfers per second, SPI-3 will significantly reduce the
overhead of parallel SCSI with the adoption of a 'low-fat'
protocol (LFP) allowing achievement of greater than 30,000 I/O's
per second.  LFP is scheduled to include an error detection
scheme along with packetization that will increase the data
integrity and provide unrestricted hot-plugging for parallel
SCSI.

SPI-3 is will also deal with the advancing developments in
silicon technology related to power management and voltage-
reduction.  These are key features of the next generation of
chips.

2.2  RECOMMENDED SCOPE OF STANDARD:

The SPI-3 standard will:
a) increase the data rate to 80 mega-transfers per second.
b) reduce the existing protocol overhead.
b) address power management and voltage reduction issues.
c) provide other capabilities which fit within the general
application scope of the this project that may be proposed during
the development phase by the participants in the project.

2.3  EXISTING PRACTICE IN AREA OF PROPOSED STANDARD:

The proposed project involves a compatible evolution of the
present SCSI physical and protocol layers.

2.4  EXPECTED STABILITY OF PROPOSED STANDARD WITH RESPECT TO
     CURRENT AND POTENTIAL TECHNOLOGICAL ADVANCE:

The nature of the proposed project is to insure that SCSI has an
upward, highly compatible growth path.  This insures that current
investments in parallel SCSI are provided with a stable managed
migration path   in the face of technological developments.

3.   DESCRIPTION OF PROPOSED PROJECT:

3.1  TYPE OF DOCUMENT:  Standard.

3.2  DEFINITION OF CONCEPTS AND SPECIAL TERMS:

LFP:      Low-fat protocol
Fast-80:  Label for associated with fundamental data rate.

3.3  EXPECTED RELATIONSHIP WITH APPROVED NCITS REFERENCE MODELS:

The SPI-3 standard is intended for use in open systems.

3.4  RECOMMENDED PROGRAM OF WORK:

The following program of work is planned for the SPI-3:
  (1)  Solicit continuing participation by the current
       membership of T10 through NCITS procedures.  Invite
       comments and proposals from organizations that may have a
       contribution to the SPI-3 standard.
  (2)  Prepare a draft proposed standard based on proposals
       submitted and other information gathered during the
       initial investigation.
  (3)  Consider the results of SPI-3 testing as may be available
       to the committee through the voluntary efforts of the T10
       membership.
  (4)  Submit the draft proposed standard to NCITS for further
       processing.
3.5  RESOURCES - INDIVIDUALS AND ORGANIZATIONS COMPETENT IN THE
     SUBJECT MATTER:

The current membership of T10 includes representatives from all
parts of the computer industry, from semiconductor chip
manufacturers to large mainframe system manufacturers as well as
government agencies.  The members of T10 have expressed their
desire to participate and cooperate in the development of this
proposed standard.

There are sufficient resources to complete the development of
this standard without delaying work on other projects.

3.6  RECOMMENDED NCITS DEVELOPMENT TECHNICAL COMMITTEE:

It is recommended that the development work be done in Technical
Committee T10 which is responsible for developing the family of
SCSI standards.

3.7  ANTICIPATED FREQUENCY AND DURATION OF MEETINGS:

Technical Committee T10 meets bimonthly. Specific task ad hoc
groups are called as may be required for one to three days
between the regular meetings but their results are not binding.

3.8  TARGET DATE FOR dpANS TO NCITS:  March 1999.

3.9  ESTIMATED USEFUL LIFE OF STANDARD:

It is anticipated that this standard will have a life of 5 years.

4.   IMPLEMENTATION IMPACTS

4.1  IMPACT ON EXISTING USER PRACTICES AND INVESTMENTS:

The proposed SPI-3 standard will provide an evolutionary growth
path to the existing practices and investments.  It is likely
that any isolated negative impacts would occur in any case
through non-standard evolution or revolution.

4.2  IMPACT ON SUPPLIER PRODUCTS AND SUPPORT:

The proposed SPI-3 standard will provide an evolutionary growth
path to the existing practices and investments.  It is likely
that any isolated negative impacts would occur in any case
through non-standard evolution or revolution.

4.3  TECHNIQUES AND COSTS FOR COMPLIANCE VERIFICATION:

The committee will consider the results of SPI-3 testing as may
be available to the committee through the voluntary efforts of
the various participants in T10.  With this method all costs are
borne by the organizations of the various participants and have
for the most part been mainly an adjunct of their normal
development costs.

4.4  LEGAL CONSIDERATIONS:

There are no known legal considerations.  A Call for Patents will
be made.

5.   CLOSELY RELATED STANDARDS ACTIVITIES

5.1  EXISTING STANDARDS:

BSR Number   Title                            Project

X3.253-1995  SCSI-3 Parallel Interconnect     0855-M
X3.292-1997  SCSI-3 Interlocked Protocol      0856-D
X3.277-1996  SCSI-3 Fast-20                   1071-M

5.2  NCITS STANDARDS DEVELOPMENT PROJECTS:

BSR Number   Title                            Project

X3.301       SCSI Parallel Interface - 2      1142-D
             SCSI Primary Commands - 2        1236-D
             SCSI Architecture Model - 2      1157-D
             SCSI Enhanced Parallel Interface 1143-DT
            
5.3  NCITS STUDY GROUPS:  None.

5.4  OTHER RELATED DOMESTIC STANDARDS EFFORTS:  None.

5.5  ISO/IEC JTC 1 STANDARDS DEVELOPMENT PROJECTS:  

It is anticipated that SPI-3 will be fast tracked for publication
as an ISO standard.

5.6  OTHER RELATED INTERNATIONAL STANDARDS DEVELOPMENT PROJECTS: None.

5.7  RECOMMENDATIONS FOR COORDINATING LIAISON:  None.

5.8  RECOMMENDATIONS FOR CLOSE LIAISON:  None.


Regards,
Lawrence J. Lamers                    ljlamers at ix.netcom.com
Adaptec, Inc.                             (408) 957-7817 
691 South Milpitas Avenue          
Milpitas, CA  95035
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