Gave up adjustability of Signature Word "AA" in specs and implementation.
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@@ -3,7 +3,7 @@
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Arbitrary Attribute Interchange Protocol
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Draft version 0.2
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Jan 26 2008
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Jan 30 2008
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Interchange of Persistent File Attributes
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@@ -19,24 +19,23 @@ Goal is to have for each file an arbitrary number of attributes which consist
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of two components (Name and Value) of arbitrary length and to have a compact
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representation of ACLs.
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This document describes a SUSP entry with adjustable name (Signature Word).
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The name is defined in an ER entry of which the content form is described here.
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Recommended is to use the name "AA" which collides neither with SUSP 1.12 nor
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with RRIP 1.12.
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The entry has been designed to be as similar to the RRIP entry SL as possible.
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This document describes a SUSP entry with Signature Word "AA" which collides
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neither with SUSP 1.12 nor with RRIP 1.12. The AA entry has been designed
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to be as similar to the RRIP entry SL as possible.
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The presence of AAIP shall be announced by a particular ER entry.
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Since the size of a SUSP entry is limited to 255, multiple entries may be
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needed to describe one component. The CE mechanism of SUSP shall be used to
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address enough storage if needed.
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The SUSP entry and the ER entry of AAIP shall only be present if the ER entry
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The AA entry and the ER entry of AAIP shall only be present if the ER entry
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of RRIP is present.
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-------------------------------------------------------------------------------
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System Entries Provided by this Specification
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* AA (or another name which does not disturb other co-existing SUSP protocols)
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* AA
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Description of the "AA" System Use Entry
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@@ -52,13 +51,12 @@ ALCs. The meaning of any other name is not specified by this document.
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All AA entries except the last one shall have the CONTINUE flag set. An AA
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entry with CONTINUE set to 0 indicates the end of the Attribute List.
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The format of the "AA" System Use Field is as follows:
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The format of the AA System Use Field is as follows:
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[1] "BP 1 to BP 2 - Signature Word" shall be (41)(41) ("AA") resp. the word
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that is defined in the ER entry. See below.
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[1] "BP 1 to BP 2 - Signature Word" shall be (41)(41) ("AA").
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[2] "BP 3 - Length" shall specify as an 8-bit number the length in bytes of
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the "AA" entry recorded according to ISO 9660:7.1.1.
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the AA entry recorded according to ISO 9660:7.1.1.
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[3] "BP 4 - System Use Entry Version" shall be 1 as in ISO 9660:7.1.1.
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@@ -73,7 +71,7 @@ The format of the "AA" System Use Field is as follows:
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| 'A' | 'A' | LENGTH | 1 | FLAGS | COMPONENT AREA |
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Within "AA" entries each component (Name or Value) shall be recorded as one
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Within AA entries each component (Name or Value) shall be recorded as one
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or more component records. If a component does not fit into the remaining
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space of an AA entry then it shall be continued in following AA entries.
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@@ -90,8 +88,8 @@ In case of discrepancies, RRIP 1.12 is the decisive specification.
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Component Records shall be recorded contiguously within each Component Area,
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starting in the first byte of the Component Area. The last Component Record
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in the Component Area of an "AA" System Use Entry may be continued in the
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Component Area of the next recorded "AA" System Use Entry in the same
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in the Component Area of an AA System Use Entry may be continued in the
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Component Area of the next recorded AA System Use Entry in the same
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System Use Area.
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Each Component Record shall have the following format:
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@@ -100,18 +98,8 @@ Each Component Record shall have the following format:
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starting with the least significant bit, as follows:
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0 CONTINUE This Component Record continues in the next
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AA Component Record.
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The following bits are defined but may not be set if the Component
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Record shall carry payload. (Their use case is unclear yet.)
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1 CURRENT This Component Record refers to the current
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directory.
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2 PARENT This Component Record refers to the parent of
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the current directory.
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3 ROOT This Component Record refers to root directory.
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all others are RESERVED and shall be 0.
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No more than one of "AA" Component Flag Bits 0-3 shall be set to ONE.
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[B] "BP 2 - Component Length (LEN_CP)" shall specify as an 8-bit number the
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number of component bytes in the Component Record. This length shall not
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include the first two bytes of the Component Record.
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@@ -281,7 +269,7 @@ Example: User id number 1001 gets associated with user name "lisa"
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Specification of the ER System Use Entry Values for AAIP:
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This ER system entry shall only be present if the ER entry of RRIP is present.
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To be compliant with SUSP-1.12, this ER entry must be present if AAIP entries
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To be compliant with SUSP-1.12, this ER entry must be present if AA entries
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are present, and ES entries have to mark RRIP and AAIP entries.
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If for some reason compliance with SUSP-1.10 is intended, then this ER entry
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and the ES entries must not be present, although SUSP-1.10 would allow ER.
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@@ -293,7 +281,6 @@ The Extension Identifier field shall be "AAIP_0002" with Identifier Length 9.
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The mandatory content form of the Extension Descriptor is
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"AA PROVIDES VIA AAIP 0.2 SUPPORT FOR ARBITRARY FILE ATTRIBUTES IN ISO 9660 IMAGES"
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with possibly two letters other than "AA" at the start of the string.
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The Description Length is 81.
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The reader of AAIP shall take the actual name of the AA entry from BP 19 and
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@@ -325,9 +312,9 @@ It also prescribes that in the case that ER entries of RRIP and AAIP are
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present, then ES entries shall be used to separate RRIP entries from AAIP
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entries.
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SUSP-1.10 does not specify ES entires at all and allows to have extension
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entries without announcing them by a ER entry. So if a second ER entry is
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not bearable, then the SUSP-1.10 downgrade of of AAIP allows to omit the
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SUSP-1.10 does not specify ES entries at all and allows to have extension
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entries without announcing them by an ER entry. So if a second ER entry is
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not bearable, then the SUSP-1.10 downgrade of AAIP allows to omit the
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AAIP ER and the ES entries. But if there is the AAIP ER then there must be ES
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at the appropriate places.
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@@ -367,11 +354,6 @@ RRIP 1.12 ftp://ftp.ymi.com/pub/rockridge/rrip112.ps
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-------------------------------------------------------------------------------
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Pending considerations:
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- shall "AA" be fixely defined as signature ?
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- shall an "ER" be issued at all ? (SUSP 1.10 would allow to omit)
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>>> mention ES because of SUSP 1.12
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- shall the tag types ACL_USER and ACL_GROUP with non-numeric qualifier be
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revoked ?
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