Draft Minutes of SSC-2 WG 2000dec06

JoeBre at exabyte.com JoeBre at exabyte.com
Mon Dec 18 15:15:56 PST 2000


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Draft Minutes 
SSC-2 Working Group 
AdHoc Meeting 
December 6, 2000 - Austin, TX 
2:00 PM - 9:00 AM 

Agenda: 

1. Introductions: Group 
2. Approval of this agenda: T10/01-011r0 Dave Peterson 
        a. Call for Secretary 
3. Approval of minutes: T10/00-412r0 Dave Peterson 
4. Review of old action items: Dave Peterson 
5. Discussion items: 
a. Explicit state change proposal T10/00-318r2 Rob Basham 
8. Unscheduled business: 
9. Next meeting requirements: 
10. Review new action items: Dave Peterson 
11. Adjournment: Group 

------------------------------------ 

The group introduced themselves. 

There was a call for secretary for this meeting. Joe Breher of Exabyte
volunteered to fulfill this role. 

The meeting Agenda 01-011r0 was approved. 

There was a call for a permanent secretary. Rob Basham of IBM indicated
that he may be able to fulfill this role effective next meeting.

The minutes of the last meeting, as embodied within T10/00-412, were
approved by the group. 

The acting secretary read action items from Meeting Minutes of 2000oct30
(T10/00-412r0). 
1) Op codes for the new commands. Action to Ralph Weber. COMPLETED 
2) Study of buffer mode requirements. Action to Rob Basham. December
goal. COMPLETED 
3) Study of statefulness of tape and how to manage it. Action to Rob
Basham. December goal. COMPLETED 
4) Study of punctuation between read series and write series. Action to
Rob Basham. December goal. COMPLETED 
5) Work with Rob Basham to structure SCC-2 document. Action to Dave
Peterson. CARRY FORWARD 
6) Schedule meeting for December. Action to Dave Peterson. Goal is to be
reviewing from the SSC document in January. COMPLETED

Rob Basham of IBM presented T10/00-318r2.pdf for a page by page review. 

The document states that there will be two tape models: Explicit and
Implicit 
Explicit will be mandatory 
Implicit will be optional 

Rob Basham of IBM made a motion the the command queing model be
optional. This was not seconded, and discussion of this point ensued.

Much discussion ensued regarding the nature of tape buffering. 

There was a distinction made between read and write in order to
constrain the discussion. 

Rob Basham of IBM requested a vote for the group to accept that Read, in
the non queued case, be truly stateless, in that it would contain an
implicit Locate. This passed 6:3.

Consensus was built regarding semantics as follows: 
Read, Non-Queueing 
- Do not validate recieved LBA against current position 
- Perform implicit Locate if necessary 
- Process Command 
Read, Queueing 
- Do not validate received LBA against current position 
- Perform implicit Locate if necessary 
- Process Command 
Write, Non-Queueing 
- Validate received LBA against current tape position 
- Return Check Condition if LBA does not match current position 
- Process command if LBA does match current position 
Write, Queueing 
- Validate received LBA against current position 
- Hold in queue until prior command(s) (with respect to LBA) arrive (if
not in order) until resources are exhausted. 
- Process commands as they can be ordered 
- Upon resource exhaustion, return Check Condition for all outstanding
commands with new (TBD) ASC / ASCQ. 

The concept of states was discussed. Joe Breher of Exabyte made a
request to enumerate the states. Rob Basham of IBM enumerated the states
thusly:

- Neutral 
- Implicit (old model) 
- ExplicitRead 
- ExplicitWrite 

The concept of Punctuation was discussed. The Punctuation Mark is a
unique CDB such that, if anything is in the queue when this CDB is
received, the CDB is rejected. Reception of the Punctuation Mark CDB
will cause a transition to the Neutral state.

An action item was assigned to Rob Basham of IBM to develop a state
chart, including transitions between states. 

Joe Breher of Exabyte objected to the change in tape processing
semantics regarding unanticipated tape marks. Historically, encountering
a tape mark during a read or space operation resulted in positioning to
the EOT side of the tape mark. The document under discussion indicates
that the tape would be positioned on the BOT side of the tape mark under
these conditions. Rob Basham of IBM noted that in his discussions with
various application vendors, Microsoft also objected to this change in
semantics. 

Paul Entzel of Quantum noted that the 16 byte Locate CDB does not allow
both Current Position and Relative Count. This may result in data
corruption during a space operation, which is invoked via the Locate
CDB.

An action item was assigned to Rob Basham to resolve the Space Block
issues. 

There was a fair amount of discussion regarding whether the new command
set becomes Mandatory for SSC-2, and the Implicit command set becomes
optional. No conclusion reached.

Joe Breher of Exabyte noted that there is no mechanism for reporting
when LBA counters overflow. The group pointed out that this is not
unique to the sequential command set. Any such problem is likely to be
solved by the disk world before it is encountered by the tape world. 

Request for Monday @ T10 in Jan 
4 hrs @ T11 in Feb 

REVIEW OF NEW ACTION ITEMS 
1) (Carry Forward) Work with Rob Basham to structure SCC-2 document.
Action to Dave Peterson. 
2) Develop a state chart, including transitions between states. Action
to Rob Basham 
3) Resolve the Space Block issues. The specific issues are that: the 16
byte CDB does not allow both Current Position and Relative Count; and
that Microsoft and Exabyte object to the change in FileMark traversal
rules. Action to Rob Basham

Attendance: 
Adaptec Moore   Dennis  dmoore at ix.netcom.com 
Amdahl  Greiner Mark    mark_greiner at amdahl.com 
Brocade Snively Bob     rsnively at brocade.com 
Cisco Systems   Peterson        Dave    dap at cisco.com 
CMD     Turenne Adrienne        
CNT     Morandi Mike    mike_morandi at cnt.com 
Crossroads      Anderson        Dexter  danderson at crossroads.com 
Crossroads      Wanamaker       Neil    ntw at crossroads.com 
Emulex  Nixon   Bob     bob.nixon at emulex.com 
ENDL    Weber   Ralph   roweber at acm.org 
Exabyte Breher  Joe     joebre at exabyte.com 
Fujitsu Fitzpatrick     Mike    mfitzpatrick at fcpa.fujitsu.com 
Hewlett Packard Spasic  Predrag predrag_spasic at hp.com 
IBM     Basham  Rob     robby at us.ibm.com 
Inrange Technology      Koellner        Greg
gregory.koellner at inrange.com 
Interphase      Seto    Pak     pseto at iphase.com 
JNI     Stuber  Craig   cstuber at jni.com 
LSI Logic       Lohmeyer        John    lohmeyer at t10.org 
LSI Logic       Miquelon        Mark    mark.miquelon at lsil.com 
LSI Logic       Weber   David   david.weber at lsil.com 
NetApp  Ford    Dave    dford at netapp.com 
Qlogic  George  Bill    bill.george at qlogic.com 
Quantum Entzel  Paul    paul.entzel at quantum.com 
Rhapsody Networks       Rangan  Venkat  venkat at rhapsodynetworks.com 
Seagate Coomes  Jim     jim_coomes at seagate.com 
Seagate Suhler  Paul    Paul_A_Suhler at seagate.com 
Sun     Moe     Ken     kenneth_moe at sun.com 
True Focus      Truestedt       Horst   hotrues at attglobal.net 


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Draft Minutes of SSC-2 WG 2000dec06 Draft Minutes 
SSC-2 Working Group 
AdHoc Meeting 
December 6, 2000 - Austin, TX 
2:00 PM - 9:00 AM Agenda: 1. Introductions: Group 
2. Approval of this agenda: T10/01-011r0 Dave = Peterson 
        a. Call = for Secretary 
3. Approval of minutes: T10/00-412r0 Dave = Peterson 
4. Review of old action items: Dave Peterson 
5. Discussion items: 
a. Explicit state change proposal T10/00-318r2 Rob = Basham 
8. Unscheduled business: 
9. Next meeting requirements: 
10. Review new action items: Dave Peterson 
11. Adjournment: Group ------------------------------------ The group introduced themselves. There was a call for secretary for this meeting. Joe = Breher of Exabyte volunteered to fulfill this role. The meeting Agenda 01-011r0 was approved. There was a call for a permanent secretary. Rob = Basham of IBM indicated that he may be able to fulfill this role = effective next meeting. The minutes of the last meeting, as embodied within = T10/00-412, were approved by the group. The acting secretary read action items from Meeting = Minutes of 2000oct30 (T10/00-412r0). 
1) Op codes for the new commands. Action to Ralph = Weber. COMPLETED 
2) Study of buffer mode requirements. Action to Rob = Basham. December goal. COMPLETED 
3) Study of statefulness of tape and how to manage = it. Action to Rob Basham. December goal. COMPLETED 
4) Study of punctuation between read series and = write series. Action to Rob Basham. December goal. COMPLETED 
5) Work with Rob Basham to structure SCC-2 document. = Action to Dave Peterson. CARRY FORWARD 
6) Schedule meeting for December. Action to Dave = Peterson. Goal is to be reviewing from the SSC document in January. = COMPLETED Rob Basham of IBM presented T10/00-318r2.pdf for a = page by page review. The document states that there will be two tape = models: Explicit and Implicit 
Explicit will be mandatory 
Implicit will be optional Rob Basham of IBM made a motion the the command = queing model be optional. This was not seconded, and discussion of this = point ensued. Much discussion ensued regarding the nature of tape = buffering. There was a distinction made between read and write = in order to constrain the discussion. Rob Basham of IBM requested a vote for the group to = accept that Read, in the non queued case, be truly stateless, in that = it would contain an implicit Locate. This passed 6:3. Consensus was built regarding semantics as = follows: 
Read, Non-Queueing 
- Do not validate recieved LBA against current = position 
- Perform implicit Locate if necessary 
- Process Command 
Read, Queueing 
- Do not validate received LBA against current = position 
- Perform implicit Locate if necessary 
- Process Command 
Write, Non-Queueing 
- Validate received LBA against current tape = position 
- Return Check Condition if LBA does not match = current position 
- Process command if LBA does match current = position 
Write, Queueing 
- Validate received LBA against current = position 
- Hold in queue until prior command(s) (with respect = to LBA) arrive (if not in order) until resources are exhausted. 
- Process commands as they can be ordered 
- Upon resource exhaustion, return Check Condition = for all outstanding commands with new (TBD) ASC / ASCQ. The concept of states was discussed. Joe Breher of = Exabyte made a request to enumerate the states. Rob Basham of IBM = enumerated the states thusly: - Neutral 
- Implicit (old model) 
- ExplicitRead 
- ExplicitWrite The concept of Punctuation was discussed. The = Punctuation Mark is a unique CDB such that, if anything is in the queue = when this CDB is received, the CDB is rejected. Reception of the = Punctuation Mark CDB will cause a transition to the Neutral = state. An action item was assigned to Rob Basham of IBM to = develop a state chart, including transitions between states. Joe Breher of Exabyte objected to the change in tape = processing semantics regarding unanticipated tape marks. Historically, = encountering a tape mark during a read or space operation resulted in = positioning to the EOT side of the tape mark. The document under = discussion indicates that the tape would be positioned on the BOT side = of the tape mark under these conditions. Rob Basham of IBM noted that = in his discussions with various application vendors, Microsoft also = objected to this change in semantics. Paul Entzel of Quantum noted that the 16 byte Locate = CDB does not allow both Current Position and Relative Count. This may = result in data corruption during a space operation, which is invoked = via the Locate CDB. An action item was assigned to Rob Basham to resolve = the Space Block issues. There was a fair amount of discussion regarding = whether the new command set becomes Mandatory for SSC-2, and the = Implicit command set becomes optional. No conclusion = reached. Joe Breher of Exabyte noted that there is no = mechanism for reporting when LBA counters overflow. The group pointed = out that this is not unique to the sequential command set. Any such = problem is likely to be solved by the disk world before it is = encountered by the tape world. Request for Monday @ T10 in Jan 
4 hrs @ T11 in Feb REVIEW OF NEW ACTION ITEMS 
1) (Carry Forward) Work with Rob Basham to structure = SCC-2 document. Action to Dave Peterson. 
2) Develop a state chart, including transitions = between states. Action to Rob Basham 
3) Resolve the Space Block issues. The specific = issues are that: the 16 byte CDB does not allow both Current Position = and Relative Count; and that Microsoft and Exabyte object to the change = in FileMark traversal rules. Action to Rob Basham Attendance: 
Adaptec Moore   Dennis  = dmoore at ix.netcom.com 
Amdahl  Greiner Mark    = mark_greiner at amdahl.com 
Brocade Snively Bob     = rsnively at brocade.com 
Cisco Systems   = Peterson        = Dave    dap at cisco.com 
CMD     Turenne = Adrienne        
CNT     Morandi = Mike    mike_morandi at cnt.com 
Crossroads      = Anderson        Dexter  = danderson at crossroads.com 
Crossroads      = Wanamaker       Neil    = ntw at crossroads.com 
Emulex  Nixon   = Bob     bob.nixon at emulex.com 
ENDL    Weber   = Ralph   roweber at acm.org 
Exabyte Breher  Joe     = joebre at exabyte.com 
Fujitsu Fitzpatrick     = Mike    mfitzpatrick at fcpa.fujitsu.com 
Hewlett Packard Spasic  Predrag = predrag_spasic at hp.com 
IBM     Basham  = Rob     robby at us.ibm.com 
Inrange Technology      = Koellner        = Greg    gregory.koellner at inrange.com 
Interphase      = Seto    Pak     = pseto at iphase.com 
JNI     Stuber  = Craig   cstuber at jni.com 
LSI Logic       = Lohmeyer        = John    lohmeyer at t10.org 
LSI Logic       = Miquelon        = Mark    mark.miquelon at lsil.com 
LSI Logic       = Weber   David   david.weber at lsil.com 
NetApp  Ford    = Dave    dford at netapp.com 
Qlogic  George  Bill    = bill.george at qlogic.com 
Quantum Entzel  Paul    = paul.entzel at quantum.com 
Rhapsody = Networks       Rangan  Venkat  = venkat at rhapsodynetworks.com 
Seagate Coomes  Jim     = jim_coomes at seagate.com 
Seagate Suhler  Paul    = Paul_A_Suhler at seagate.com 
Sun     = Moe     Ken     = kenneth_moe at sun.com 
True Focus      = Truestedt       Horst   = hotrues at attglobal.net 
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