ISO 8571-2:1988/Amd 1:1992
(Amendment)Information processing systems — Open Systems Interconnection — File Transfer, Access and Management — Part 2: Virtual Filestore Definition — Amendment 1: Filestore Management
Information processing systems — Open Systems Interconnection — File Transfer, Access and Management — Part 2: Virtual Filestore Definition — Amendment 1: Filestore Management
Amends Introduction, clauses and subclauses 1, 5, 6, 9.1, 9.5, 12, 13.2, 13.9, 13.11, 13.12, 14, 14.1 to 14.5, 15, adds subclauses 5a, 6.1, 7a, 9a to 9d, 11a to 11c, 12a, 13.13 to 13.20.
Systèmes de traitement de l'information — Interconnexion de systèmes ouverts — Transfert, accès et gestion de fichiers — Partie 2: Détermination du système de fichiers virtuel — Amendement 1: Gestion du système de fichiers
General Information
Relations
Standards Content (Sample)
INTERNATIONAL
STANDARD 857 I-2
First edition
1988-IO-01
AMENDMENT 1
1992-12-15
Information processing systems - Open Systems
Interconnection - File Transfer, Access and
Management -
Part2:
Virtual Filestore Definition
AMENDMENT 1 : Filestore Management
Technologies de /‘information - lnterconnexion de systemes ouverts (OS/) -
Transfert, acctk et gestion de tkhiers -
Partie 2: Dkfinition du systkme de fichiers virtue/
AMENDEMENT I : Gestion du systhme de fichiers
- -
= =
IT =
= Z
: ;
II
=
=
Reference number
:a
IS0 8571-2:1988/Amd.1:1992 (E)
IS0 857192:1988/Amd.1:1992 (E)
Foreword
IS0 (the International Organization for Standardization) and IEC (the International
Electrotechnical Commission) form the specialized system for worldwide
standardization. National bodies that are members of IS0 or IEC participate in
the development of International Standards through technical committees
established by the respective organization to deal with particular fields of
technical activity. IS0 and IEC technical committees collaborate in fields of
mutual interest. Other international organizations, governmental and non-
governmental, in liaison with IS0 and IEC, also take part in the work.
In the field of information technology, IS0 and IEC have established a joint
technical committee, lSO/IEC JTC 1. Draft International Standards adopted by the
joint technical committee are circulated to national bodies for voting. Publication
as an International Standard requires approval by at least 75 % of the national
bodies casting a vote.
Amendment 1 to International Standard IS0 8571-21988 was prepared by Joint
Technical Committee lSO/IEC JTC 1, Information technology.
IS0 8571-2 consists of the following parts, under the general title information
Open Systems Interconnection - File Transfer, Access and
processing systems -
Management
- Part 7 : General introduction
- Part 2 : Virtual Filestore Definition
- Part 3 : File Service Definition
- Part 4 : File Protocol Specification
- Part 5 : Protocol Implementation Conformance Statement Proforma
0 lSO/IEC 1992
All rights reserved. No part of this publication may be reproduced or utilized in any form or by
any means, electronic or mechanical, including photocopying and microfilm, without
permission in writing from the publisher.
lSO/IEC Copyright Off ice Case postale 56 l CH-1211 Geneve 20 l Switzerland
Printed in Switzerland
ii
IS0 857%2:1988/Amd.1:1992 (E)
Information processing systems - Open Systems
Interconnection - File Transfer, Access and Management -
Part2
Virtual Filestore Definition
AMENDMENT 1 : Filestore Management
NOTE - This amendment has additional subclauses and tables to IS0 8571 which are indicated by the use of lower case
Roman letters beginning with “a” and imply ordering alphabetically, following the clause with the same numerical value in
IS0 8571. These and all subsequent subclauses, tables, and cross references will be renumbered in subsequent editions.
1 Scope and field of application
Introduction
(amend 1st paragraph)
(amend 3rd paragraph, page 1)
This part of IS0 8571
IS0 8571 defines services for file transfer, access and
It also specifies a protocol available
management.
a) defines an abstract model of the virtual filestore
within the application layer of the Reference Model.
for describing files and filestores (see section
The service defined is of the category Application
one);
Service Element (ASE). It is concerned with
identifiable bodies of information which can be treated b) defines the set of Actions available to manipulate
as files, stored and managed within open systems, or the elements of the model (see section two);
passed between application processes.
c) defines the properties of individual objects and
(amend 4th paragraph, page I) associations in terms of attributes (see section
three).
IS0 8571 defines a basic file service. It provides
defines the form of representations of files
sufficient facilities to support file transfer, file access,
d)
and management of files stored on open systems. with hierarchical structures (see clause 7 in
IS0 8571 does not specify the interfaces to a file section one).
transfer, access or management facility within the local
system.
IS0 8571-2:1988/Amd.l:1992 (E)
Section one: The filestore model
5 Basic concepts 5a The virtual filestore model
5a.l Fliestore Objects
(amend 3rd paragraph (atier note), page 2)
A filestore may contain an arbitrary number (greater A virtual filestore is comprised of one or more of three
than or equal to one) of objects (see figure 1). kinds of objects:
files;
(amend 4th paragraph, page 2)
a)
The properties of each object are defined by the file-directories;
b)
values of a set of object attributes. These attributes
references.
C)
are global; at any one time, a single attribute value is
available to all initiators. Different object types may 5a.l .I Files
have distinct types of attributes, as well as types of
File objects contain data, and provide structuring
attributes in common.
information to access the data within them (see clause
(add following paragraph 5, page 2) .
7)
Each file-directory maintains a parenthood relationship 5a.l.2 File-directories
with zero or more subordinate objects. Some of the
File-directory objects maintain a set of relationships to
file-directory attributes may identify access control
zero or more other objects within the filestore, whether
information to subordinate objects.
those objects are files, references, or other file-
Each reference maintains a link to exactly one other directories. This relationship is parenthood. A file-
object. The referent is either a file or a file-directory. directory is said to be the parent of an object if it
The identity of the referent is available as an attribute maintains the relationship of parenthood for that
of the reference, in the form of a (possibly incomplete) object. Similarly, an object is said to be the child of a
primary pathname. This attribute can not be changed. specified directory if that directory is the object’s
Other reference attributes may identify the object type parent. In this way, file-directories provide a means of
and access control information to the linked object. If grouping objects within the virtual filestore. These
the identity of the referent changes, the corresponding groups can then be used to provide a structural order
reference ceases to exist (the filestore tree) to the data files within the filestore.
(amend 7th paragraph, page 3) An object is ‘in’ a file-directory if either
The first are in one to one correspondence with the a) that file-directory is the parent of the object
object attributes, and indicate the active value of those
b) there is a reference who’s parent is the file-
attributes as perceived by the initiator.
directory, linking to the object.
(amend 9th paragraph, pages 3 and 4)
An object is ‘under’ a file-directory if either
An arbitrary number (greater than or equal to zero) of
a) the object is in the file-directory
initiators may have initialized FTAM regimes at any
one time. Exchanges between the initiator and the b) the object is in another file-directory that is under
(Note this is a recursive
responder lead to the selection of at most one object in the file-directory.
definition. )
the responder’s virtual filestore to be bound to a
particular RAM regime at any one time. Note that
5a.l.3 References
multiple file objects may be identified for later selection
via the generalized selection service. However only Reference objects maintain exactly one relationship to
That -
one object may be selected at a time. Further, no exactly one other object within the filestore.
guarantees are placed on the availability of any file relationship is linkage. The object % linked by the
object in this group if it is eventually selected. reference must be either a file or a file-directory. The
structure defined by the parent and linkage relations is
(add after clause 5, page 4)
called the filestore structure.
IS0 8571-2:1988/Amd.l:1992 (E)
5a.2 Filestore structure Objects within a virtual filestore may be referenced by
complete pathname, or by an incomplete pathname.
Every virtual filestore has a root object. The root is the
In the latter case, the responder resolves the
only object in the filestore that has no parent. This
incomplete pathname to a complete pathname using
root is either a file or a file-directory. It cannot be a
the current name prefix. The file protocol is designed
reference.
In the case where it is a file, that file will be
such that the responder need not reveal the current
the only object within that filestore.
name prefix to the initiator, should it be desirable to
The relationship of parenthood results in a hierarchical
conceal the filestore structure above this file-directory
model of the filestore, where the root node is
for security or other reasons.
represented by the filestore root object, intermediate
5a.3.2 Resolving a pathname
nodes are represented by file-directories maintaining
at least one parenthood relationship, and leaf nodes
A complete pathname is resolved to an object by a
are represented by files, references, and file- series of steps using the object names of the
directories maintaining no parenthood relationships. pathname to locate the intermediate objects along the
path in turn.
References may be used for convenience of access in
special situations, or for special security needs. Initially, the root node is located.
References provide a simple means of allowing an
For each step, while object names of the pathname
object to appear in more than one place in the filestore
remain to be resolved:
hierarchy without having to duplicate the object, or
worry a) if the object located is a reference, and the
about maintaining consistency between
duplicate objects. In normal use a user will not filestore user has passthrough access to this
observe any difference in behavior whether an object reference, then the object which it references is
is accessed via parenthood or reference. located (if the user does not have passthrough
access to this reference, or if the referenced
5a.3 Name resolution
object is not found, an error is reported);
An object is identified within the virtual filestore by a
b) if the object located is a file-directory, and the
pathname. A pathname is comprised of a series of
filestore user has passthrough access to this
object names.
Each object name in the series
file-directory, then the child object named by the
identifies the next child object in the virtual filestore.
next object name of the pathname is located (if
The last object name in the series identifies the target
the user does not have passthrough access to
object. The root object in a filestore is identified by a
this directory, or the next object name does not
pathname comprised of zero object names. The exact
correspond to any child of this directory, an error
algorithm is described in 5a.3.2.
is reported);
5a.3.1 The current name prefix
c) if the object located is a file, then an error is
When the pathname of an object begins its series of reported.
object names at the root of the filestore, it is called a
If the object located when all object names of the
complete pathname. Otherwise, to uniquely identify
pathname have been exhausted is a reference, then
an object within the virtual filestore, the incomplete
the final action taken depends on the operation being
pathname must be resolved to a complete pathname.
performed:
This is done with the current name prefix activity
attribute. The current name prefix is assigned to the d) if the operation is specific to reference objects,
association by the responder. The current name prefix then the operation is performed on the reference
is a complete pathname of a file-directory object. The object located;
actual mechanisms for this assignment are outside the
e) if the operation is not specific to reference
scope of FTAM, but possible uses could be for
objects, then the object to which the reference
providing default file-directories to users, protecting
refers is located, and the operation is performed
filestore users from potential filestore organizational
on the referenced object.
changes, or for enhanced security control.
5a.4 Object type checking
An incomplete pathname is resolved to a complete
If the object located when a pathname is resolved is
pathname by prepending the series of object names
within the current name prefix to the incomplete not of the type required for the operation to be
pathname. performed then an error is reported.
IS0 8571.2:1988/Amd.l:1992 (E)
- directory
0 - reference
- - parenthood
e - linkage
Figure la - An example tree structure of a VFS
5a.5 Example GJKD
c)
Thus for file selection, the filestore in this example
Figure la shows an example of a filestore containing
appears as if duplications of data took place as in
references.
figure 1 b.
The file F has primary pathname E,F. However, it may
NOTES
also be accessed by the following names involving
references:
1) In normal use, except when explicit manipulation of the
reference object is carried out, a user will not observe
a) AD
any difference in behaviour whether an object is
b) WV=
accessed via parenthood or reference.
D
COPY
of F
COPY COPY D
COPY
of B of c
of F
\ f .
Figure 1 b - An example of the apparent structure of a VFS
IS0 857%2:1988/Amd.l:1992 (E)
2) References may be used for convenience of access in generalized selection group activity attribute. Inclusion
special situations. References may have, in conjunction
in this group is based on the attribute assertions
with the path access control attribute, applications to
provided by the initiator.
Access permission by the
security and secure views of the filestore structure.
initiator to the files based on requested actions and
access authorization provided by the initiator is
(amend title of clause 6, page 4)
implicitly an assertion in identifying the group of
pathnames.
6 Object selection
NOTE -The generalized file selection mechanism does not
(amend 1st paragraph, page 4)
imply formal selection of the objects identified by
From outside the filestore, selection of an object is
pathname within the generalized selection group. It merely
always made using the pathname of the object. Even collects the pathnames for later use in other operations.
...
Questions, Comments and Discussion
Ask us and Technical Secretary will try to provide an answer. You can facilitate discussion about the standard in here.