P1394> units and logical units definition

P1394> units and logical units definition

Atsushi_Nakamura atsnaka at bsd.canon.co.jp
Mon Mar 16 06:58:11 EST 1998


I have a questions about the current profile.


I am still wondering if the usage method of SBP-2
logical units(and "unit"s) in the printer profile 
matches with the meaning of logical units 
described in SBP-2.


In the SBP-2 spec, it says ;


  "A logical unit is part of the unit architecture and is
   an instance of a device model e.g., mass storage, 
   CD-ROM or printer"


In section 17:Model Configuration of document 0.1d -PWG 
printer profile, it says ;


  "Each unique combination of the above information represents
    a unique service provided by the device and is identified as a 
    separate Unit within the device. Zero or more instances of
    a unit may exist within the device at any given time. 
    All instances of a unit have identical functionality."


It may be my lack of mis-understanding, but doesn't the 
2 statements conflict ? 
SBP-2 considers logical units as instances of "device" models
whereas the printer profile considers logical units as instances
of a "logical channels".


If there is 1 instance of a printer device with multiple 
SBP-2 logical channels, how do I address this device as a
unit architecture following both rules ?


1 "printer" unit with 2 logical unit directories?... 
but then,a logical unit has to be "an instance" of a 
device model,so there should be only 1 logical unit ????
 
Ats










-----------------------------------------
Atsushi Nakamura
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BJ Technology Develpoment 22,
Canon Inc.


53 Imai Kami-cho
Nakahara-Ku, Kawasaki-shi
postal no. 211


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email(1):Atsushi_Nakamura at cbj.canon.co.jp
email(2):atsnaka at bsd.canon.co.jp
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