Minutes of the Printer MIB Working Group (PRINTMIB)
An interim meeting of the PRINTMIB Working Group was held in Arlington,
Virginia (near Washington DC) on 26 and 27 April 1994.
There was a discussion on what the various objects would be used for and
who would be using them. Discussion focused on the imageable area
object and whether it should be provided by interpreter or for the whole
machine.
Discussion of Open Issues
The following issues are being tracked for closure.
1. Is the media group optional?
Leave MediaExtended as optional, media information in the
InputTable will remain mandatory.
2. Will the MIB/MIF support multiple consoles?
No, do with private extensions, a single ``console'' that contains
the data for all the consoles, or some other means.
3. Is General Printer a table?
No, support Virtual printers through some other means such as
private extensions, etc.
4. How does ``character set'' tie into ``channel''?
There was no identified need to tie character set to channels.
Character Set is more closely tied to the interpreter or console
and those objects are tied to localization and character set
settings.
5. Static versus dynamic - how efficient will this be?
Because there is no distinction between static and dynamic
information in SNMP, the printer must implement all the information
so the agent can report it.
6. The MIB/MIF consist of 58 objects - is that too many?
OPEN --- Defer for final review.
7. Should we endorse some type of interlock method for all the
writable objects?
OPEN --- One of the reasons it remains open is that there is no
defined method for this function for DMTF.
8. Should we use separate community names or additional index to
support multiple printers being managed through a printer server?
Use community names with predictable ``numbering'' for each device.
Randy Turner (QMS) will write up a proposal for inclusion in the
RFC.
9. Should paper size be writable?
Yes, to tell a printer that can't detect paper size what size paper
is loaded.
10. Should units be writable?
Yes, but manufacturers may choose to only implement R/O access.
Persistence across power cycles may vary from manufacturer to
manufacturer.
11. Should size units be only in millimeters?
No, but we will reduce the number of units wherever possible.
12. How should out of range sets be handled - reject or snap to the
nearest?
Snap to the nearest integer and reject an invalid ENUM. The data
returned in the SNMP packet will indicate the value of the integer
snapped to.
13. Are ``Input - dimensions extended'' mandatory?
This will remain at best optional; possibly could be removed.
14. In what units is printable area reported?
.0001 inches or .001 mm
15. Should media type be a string or an enum?
String, recommend using ISO DPA, ISO SPDL names where possible.
16. How do we associate media with inputs, outputs with finishers, etc?
Input: The only media that is described is the media in an input
tray and it is described there.
Outputs: OPEN - Harry Lewis to make a proposal
17. Do margins (or imageable area) need to be PDL specific?
No, but this object may not be needed.
18. Does ``other'' have a meaning for objects which normally have an
integer value?
Yes - potential meanings are defined with the object where it
applies.
19. Is ``unknown'' the same as ``uninitialized'' and if not how do you
tell the difference?
Possibly, if the object's value is ``unknown'' failing when
attempting to write to it means the object is truly unknown. If
writing is successful, the object's value was just unitialized.
20. Should default interpreter be by channel or overall?
OVERALL. There is a hierarchy used to determine the interpreter:
o If contained in the datastream, used that interpreter
o Otherwise use the default for the channel
o Otherwise use the default for the interpreters
o Otherwise the default interpreter is undefined or manufacturer
specific
21. How do we handle the ``parallel in, serial out'' channel?
Ignore it
22. Is ``console width'' ``string width'' or ``screen width''?
Closed by addressing issue #23.
23. Is ``number of lines'' and ``number of characters'' of the console
mean physically or logical?
They refer to the physical size of the console.
24. Which strings are localized and controlled by ``current
localization''?
Spec has been updated to reflect which strings are localized by
CurrentLocalization, which strings are localized by
ConsoleLocalization and which strings are not localized. String
not specifically stated to be localized should not be localized as
that data may be used to make decisions.
25. Do we need an ``ID'' object for each table ``index''?
OPEN
26. Are all consoles using the same language?
We only support one console.
27. Should we enable or disable a channel as a whole or provide a way
to selectively enable and disable ``data'' and ``control'' flows on
a channel?
No convincing argument for separation of control and data.
Therefore, the answer is no.
28. Is the consistent use of 1,2 (for enums) and -1, -2 (for integers)
to represent ``other'' and ``unknown'' consistent with SNMP
``tradition?''
There is a tradition of having certain distinguished values but
those values often vary from RFC to RFC. Consistent of use of these
values within the PRINTER MIB should be OK.
29. How should channel relate to underlying layers and to other
existing MIBS?
There is a pointer to the interfaces MIB. While this is not a
complete solution, it is sufficient for this implementation.
``A channel is an independent source of print/control data which
can be enabled or disabled, is directable to an interpreter, and
its output is suitable for the interpreter.''
(There was a long discussion on how channels are linked to the
underlying layers. This discussion included the issue of how to
deal with a WPS printer: where is the channel - within the PC or
across the 1284 parallel port to the physical printer? In order to
restrict the scope of the work, the group will focus on the
physical printer device. Environments like WPS and the SUN printer
will fit in the model but the details of that management
implementation is up to the manufacturer.)
30. How well does the Host MIB work for the system controller?
The HOST MIB is probably overkill for a printer but the work needed
to get the SNMP community to agree to have new objects in the
printer MIB that largely duplicate host MIB objects is too great.
(Is there work in progress to create a MIF which corresponds with
the HOST MIB? Since the channel group uses the interfaces table
from MIB II, how is this done with DMTF?)
31. How much of the Host MIB is mandatory for the system controller?
As defined in the Host MIB (RFC 1514) particularly hrSystem and
hrStorage and hrDevice groups.
32. What is the difference between INTEGER and INTEGER32?
INTEGER is used for ENUMs and INTEGER32 for values.
33. Do we need and ``everything back to OK status'' alert?
No, applications should scan the alert table.
34. Should the console be writable?
Yes: Addressed by issues #22 and #23 and therefore closed.
35. Should Company names be included in channels? Interpreters?, etc?
Yes - to exclude them would make some of the names less clear.
36. Should objects in the channel group relate to the ISO seven layer
model?
No attempt will be made to correlate the channels to the ISO model.
37. Should the default orientation be by interpreter or overall?
Overall only.
38. Should we include an operator panel lock object?
Yes
39. Is the description field of the alert table localized when inserted
in the table or when the table is accessed?
This is vendor implementation specific. The recommendation of the
group was that the best implementation would be to localize when
the table is accessed.
Rakesh Mahajan reviewed the work going on in the Multifunction
Peripheral Group. He outlined where the group originated. He indicated
there was some overlap between that group's work and the Microsoft at
Work architecture.
Joel will be generating a draft to be distributed using the IETF
mechanism.
Potential Areas for Afternoon Discussion
o Expanding finishing enums
o Clear out notes in summary tables
o Scope of our mission
- needs of driver developers
- fonts, spoolers, print servers, virtual printers
o x-ray mode (from Canon)
o Interfaces
o Referencing other RFCs
Cleaning Out the Notes
o A stab was made at providing a list of enumerated finisher
consumables.
o Joel will publish with FINISHER as currently defined. Stan
McConnell will review and make necessary changes in the next week.
o Media Path units will remain as scalars outside the table as there
was no perceived need to allow it to vary by media path.
All objects will start with ``prt.'' Abbreviations of the groups in the
MIB/MIF should be:
General Printer: GP
Input: In
Output: Out
Finisher: Fin
Marker: Mkr
Media Path: MP
Channel: Ch
Console: Con
Interpreter: Intpr
Alert: Alert
Other abbreviations:
CrossFeed: XFeed
Dimension: Dim
Language: Lang
Capacity: Cap
Description: Desc
Default: Dflt
Objects
There are currently (as of these minutes) 88 mandatory and 47 optional
objects.
A discussion occurred focused on potential ways to reduce the number of
objects to address a potential perceived problem from within the SNMP
community.
Printable areas was changed to margins and moved to the marker. It now
represents the ``safe'' printable area taking into consideration the
marker, the medium and all interpreters. (92 mandatory, 43 optional (25
Mandatory Read-Write))
Discussion on the issue of synchronization or atomicity.
