Subject: P1394> May 1394 PWG Definitions

From: [email-masked]
Date: Thu, 21 May 1998 15:05:08 -0700

Here are the definitions that we came up with at the May 1394, PWG meeting. We 
did not achieve rough consensus on the definitions for a queue and a function so
please comment.

Thanks,
Alan

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Unit: Synonymous with a Unit Directory. A unit has a one to one correspondence 
with a device driver. From SBP-2: A component of a Serial Bus node that provides
processing, memory, I/O or some other functionality. Once the node is 
initialized, the unit provides a CSR interface that is typically accessed by 
device driver software at an initiator. A node may have multiple units, which 
normally operate independently of each other. Within this standard, a unit is 
equivalent to a target.

Service: A sub component of a unit that operates on a set of tasks independent 
of other services of the same unit. For SBP-2, there is a one-to-one 
correspondence between a service and a logical unit (LUN). For example, a 
printer (unit) might implement a PDL service responsible for data flow to the 
printer and a management service responsible for control and status.

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Queue: A collection of ORBS that proceed or block independent of other queues.

by Atsushi Nakamura
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My shot at definition of "function":
A function is part of the unit architecture and is an instance of a device 
model, e.g.,   mass storage, CD-ROM or printer. A function is usually a 
collection of services that are user identifiable.
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The definition of a function seems to indicate that a function is a unit.

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From: Randy Turner <[email-masked]>
Date: Thu, 21 May 1998 21:34:10 -0700

Hi guys,

Help me refresh my memory.

The definition of a service below says there is a one-to-one correspondence
between a LUN and a service, and that services are independent of each
other. Does this imply that LUN (1)  and LUN (2) within a particular unit
CANNOT be "instances" of the same service?

Randy