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N/A                                                            A. Deason
Internet-Draft                                               Sine Nomine
Intended status: Informational                           August 26, 2011
Expires: February 27, 2012


                      Base Types for Time in AFS-3
                     draft-deason-afs3-type-time-03

Abstract

   This document defines three types to be used in future AFS-3 Rx
   Remote Procedure Calls (RPCs) to represent time.  Current AFS-3 RPCs
   represent time as 32-bit integers representing seconds.  This is
   insufficient in both granularity and range, so new types to represent
   time are defined in this document to overcome these limitations.

Internet Draft Comments

   Comments regarding this draft are solicited.  Please include the
   AFS-3 protocol standardization mailing list
   (afs3-standardization@openafs.org) as a recipient of any comments.

Status of this Memo

   This Internet-Draft is submitted in full conformance with the
   provisions of BCP 78 and BCP 79.

   Internet-Drafts are working documents of the Internet Engineering
   Task Force (IETF).  Note that other groups may also distribute
   working documents as Internet-Drafts.  The list of current Internet-
   Drafts is at http://datatracker.ietf.org/drafts/current/.

   Internet-Drafts are draft documents valid for a maximum of six months
   and may be updated, replaced, or obsoleted by other documents at any
   time.  It is inappropriate to use Internet-Drafts as reference
   material or to cite them other than as "work in progress."

   This Internet-Draft will expire on February 27, 2012.

Copyright Notice

   Copyright (c) 2011 IETF Trust and the persons identified as the
   document authors.  All rights reserved.

   This document is subject to BCP 78 and the IETF Trust's Legal
   Provisions Relating to IETF Documents
   (http://trustee.ietf.org/license-info) in effect on the date of



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   publication of this document.  Please review these documents
   carefully, as they describe your rights and restrictions with respect
   to this document.


Table of Contents

   1.  Introduction . . . . . . . . . . . . . . . . . . . . . . . . .  3
   2.  Conventions Used in this Document  . . . . . . . . . . . . . .  3
   3.  Data Types . . . . . . . . . . . . . . . . . . . . . . . . . .  4
     3.1.  AFSAbsTime64 . . . . . . . . . . . . . . . . . . . . . . .  4
     3.2.  AFSRelTime64 . . . . . . . . . . . . . . . . . . . . . . .  4
     3.3.  AFSAbsTime64Res  . . . . . . . . . . . . . . . . . . . . .  5
       3.3.1.  Resolution Assumptions . . . . . . . . . . . . . . . .  6
   4.  Time Resolution  . . . . . . . . . . . . . . . . . . . . . . .  6
     4.1.  Sources of Differing Time Resolutions  . . . . . . . . . .  6
     4.2.  Relevance to AFS-3 . . . . . . . . . . . . . . . . . . . .  7
     4.3.  When to Include Resolution Information . . . . . . . . . .  7
   5.  Resolution Limitations . . . . . . . . . . . . . . . . . . . .  8
   6.  Times Before UTC . . . . . . . . . . . . . . . . . . . . . . .  9
   7.  Converting Time Types  . . . . . . . . . . . . . . . . . . . .  9
     7.1.  Special Cases  . . . . . . . . . . . . . . . . . . . . . . 10
     7.2.  Sample Code  . . . . . . . . . . . . . . . . . . . . . . . 10
   8.  Security Considerations  . . . . . . . . . . . . . . . . . . . 13
   9.  IANA Considerations  . . . . . . . . . . . . . . . . . . . . . 13
   10. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 13
   11. References . . . . . . . . . . . . . . . . . . . . . . . . . . 13
     11.1. Normative References . . . . . . . . . . . . . . . . . . . 13
     11.2. Informative References . . . . . . . . . . . . . . . . . . 13
   Author's Address . . . . . . . . . . . . . . . . . . . . . . . . . 14





















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1.  Introduction

   All extant AFS-3 RPCs represent time as a 32-bit integer, as encoded
   by XDR in [RFC4506], which represents a number of seconds.  For RPCs
   that specify an absolute time, this is the number of seconds that
   have passed since since midnight or 0 hour January 1, 1970
   Coordinated Universal Time (UTC), not counting leap seconds.  These
   time structures will be unusable after January 2038, and are already
   insufficient to represent time with more granularity than one second.

   This limited granularity creates inefficiencies in various parts of
   the AFS-3 protocol when it must be determined in what order two
   events have occurred (for example, whether or not a file was changed
   since the last time a volume has been backed up).  When those two
   events have occurred during the same second, implementations must
   take a conservative assumption about which event occurred first,
   often resulting in unnecessary duplication or retransmission of data.
   In addition, metadata can be lost when files are copied to AFS from
   other filesystems that store file modification times with finer
   granularity than one second.

   This document defines three new types to represent time to overcome
   these limitations: AFSAbsTime64, AFSRelTime64, and AFSAbsTime64Res.
   All of these support a much wider time range at a much higher
   granularity than the current time representations.  AFSRelTime64 is
   to be used to represent times relative to some other event, and
   AFSAbsTime64 is to be used to represent absolute time stamps.
   AFSAbsTime64Res is to be used to represent a small range of absolute
   time, which is necessary for determining relative ordering of events,
   as described in Section 4.

   All of these new types also have the additional benefit of providing
   standard type identifiers to be used when specifying absolute or
   relative time in AFS-3 RPC arguments and structures.  Currently, all
   time values are just defined as "afs_int32" types in the XDR language
   definitions.  This can make it confusing whether or not a field is an
   absolute time, relative time, or something else completely.  Using
   the new standard time types will make this clear and unambiguous.


2.  Conventions Used in this Document

   The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
   "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
   document are to be interpreted as described in [RFC2119].






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3.  Data Types

   This document defines three new data types: AFSAbsTime64,
   AFSRelTime64, and AFSAbsTime64Res. All of these are encoded on the
   wire using the XDR standard described in [RFC4506], and are described
   using the XDR language specification therein.

3.1.  AFSAbsTime64

   The new AFSAbsTime64 type is represented as an XDR-encoded 64-bit
   signed integer representing the timestamp.  It is defined as thus in
   XDR:

       typedef hyper AFSAbsTime64;

   The AFSAbsTime64 type represents time relative to midnight or 0 hour
   January 1, 1970 Coordinated Universal Time (UTC), represented in
   increments of 100 nanoseconds (ns).  If the value is greater than
   zero, the value represents the amount of time that has passed since
   midnight January 1, 1970 UTC, excluding any leap seconds.  If the
   value is less than zero, the value represents the amount of time
   before midnight January 1, 1970 UTC.

   For example, to represent the time 60 seconds after midnight on
   January 1, 1970 UTC, the value of the field would be 600000000 (600
   million).  To represent the time 60 seconds before midnight January,
   1970 UTC, the value of the field would be -600000000 (negative 600
   million).

   This type can represent any time in the year 27258 BCE through any
   time in the year 31196 CE with 100-ns granularity.  For timestamps
   before 1972, see the notes in Section 6.

3.2.  AFSRelTime64

   The new AFSRelTime64 type has same representation on the wire as
   AFSAbsTime64 in Section 3.1:

       typedef hyper AFSRelTime64;

   The AFSRelTime64 type represents an amount of time that has passed
   since some other event, represented in increments of 100 nanoseconds
   (ns).  The event to which this time is relative is unspecified, and
   can be anything; it must be specified by the RPC or structure that
   defines a field of the AFSRelTime type.

   Values greater than 0 represent dates that occur after the relative
   event, and values less than 0 represent dates that occur before the



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   relative event.

   For example, to represent the time 5 seconds before some other event,
   the value of the timestamp field would be -50000000 (negative 50
   million).

3.3.  AFSAbsTime64Res

   The new AFSAbsTime64Res type is represented as an XDR-encoded
   structure on the wire, containing an AFSAbsTime64 and a 32-bit
   unsigned integer representing the resolution.  It is defined as thus
   in XDR:

       struct AFSAbsTime64Res {
           AFSAbsTime64 timestamp;
           unsigned int resolution;
       };

   The AFSAbsTime64Res structure represents the amount of time that has
   passed since midnight or 0 hour January 1, 1970 Coordinated Universal
   Time (UTC), excluding any leap seconds.  The value of the timestamp
   field is this amount of time represented as described in Section 3.1.

   The resolution field represents the resolution of the time source
   from which the timestamp was obtained.  The value of the resolution
   field is the difference between the represented time, and another
   time after the represented time that is guaranteed to be after the
   actual time at which the event in question occurred.

   In other words, let X be the time that some event occurred, Y be the
   value of the timestamp field in an AFSAbsTime64Res structure, and Z
   be the value of the resolution field.  To construct an
   AFSAbsTime64Res structure that represents X, the values of the
   timestamp and resolution field MUST be specified such that Y <= X < Y
   + Z. Typically the value of the resolution field will just be the
   resolution of the time source from which the timestamp was obtained,
   if the resolution of the time source is constant.

   For example, to represent the time 60 seconds after midnight on
   January 1, 1970, the value of the timestamp field would be 600000000
   (600 million) as described in Section 3.1.  If this time stamp was
   obtained from a source that only represents time in seconds, the next
   representable time is 61 seconds after midnight on January 1, 1970,
   so it is guaranteed that the event in question occurred before that
   time (otherwise the time source would give us a time of 61 seconds).
   So the value of the resolution field should be 10000000 (10 million).
   In effect, this AFSAbsTime64Res structure represents an event that
   occurred at or after 60 seconds after January 1, 1970, but occurred



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   before 61 seconds after January 1, 1970.

   For more details about the resolution field (including the motivation
   for its existence), see Section 4.

3.3.1.  Resolution Assumptions

   If the resolution field has the value of 0, the resolution of the
   specified timestamp is unknown.  If an implementation has absolutely
   no mechanism to determine the resolution of a time source when
   creating a time stamp, it MUST specify a resolution of 0.  If an
   implementation needs to use an AFSAbsTime64Res value for calculating
   event ordering, and the resolution is 0, it SHOULD assume a
   resolution of 1 second, and round the timestamp down to the nearest
   second.

   An AFS-3 implementation MUST NOT ever specify a resolution greater
   than 1 second (10000000 100-ns increments).  Implementations of the
   AFS-3 protocol that exist prior to the introduction of the new time
   types in this document assume that the time resolution is 1 second,
   and may not behave correctly with time sources that are less granular
   than 1 second.  No systems nor file formats that are related to any
   AFS-3 implementation are known that do not have at least 1-second
   granularity, so adhering to this should not be a problem.

   If an implementation receives an AFSAbsTime64Res structure with a
   granularity coarser than 1 second, it MUST treat it as an invalid
   time representation.  What that entails depends on the context, but
   the AFSAbsTime64Res value MUST NOT be used for any calculations and
   SHOULD be immediately discarded.  Typically an RPC will raise some
   kind of error in this condition, but the exact behavior is up to the
   relevant RPC or other operation.


4.  Time Resolution

   The new type AFSAbsTime64Res includes information about the
   resolution or granularity of the time it represents.  The reason for
   including this information may not be immediately clear, so this
   section provides some information on why this information is
   beneficial.

4.1.  Sources of Differing Time Resolutions

   All current AFS-3 implementations represent time as a 32-bit integer
   on the wire, and so it is common for implementations to internally
   represent time as 32-bit integers, with 1-second granularity.  As
   such, when implementations support the time types defined in this



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   document, it is likely that there will be a period of time where
   implementations cannot store or represent time with greater
   granularity than 1-second, even though the protocol allows them to do
   so.

   In addition, due to technical restrictions of various platforms, or
   other sources of time (such as file formats), implementations may be
   only able to transmit time information in certain granularities.  For
   example, the operating system that an AFS-3 Volume Server
   implementation runs on may only be able to retrieve the current time
   in increments of 1 millisecond.  Or, an AFS-3 Volume Server
   implementation may be reading the time information from a file, and
   the file only represents time in increments of 1 second.

   From this, it is clear that implementations will send time of various
   granularity when communicating with other services and clients in
   AFS-3, and the granularity of time may vary even within the same
   implementation process (depending on from where it is obtaining the
   time).

4.2.  Relevance to AFS-3

   Timestamps are sometimes used in AFS-3 to establish a relative non-
   strict total ordering of events.  That is, given the events X and Y,
   we must determine whether X or Y occurred first, or if they occurred
   at approximately the same time.  This primarily occurs in volume
   operations when incremental data is sent, and exactly what
   incremental data is sent is determined by the timestamps of other
   volumes.  If we get the ordering wrong, problems with data
   inconsistency can occur.  If we conservatively determine that two
   events occurred at the same time when we could have correctly made
   the determination that one occurred before the other, inefficiencies
   arise.

   In order to be able to order such events, then, we must know the
   resolution of the time value that is stored.  This is so we know the
   earliest possible time that the event occurred, and the latest
   possible time that the event occurred.

4.3.  When to Include Resolution Information

   There are two time types defined in this document to represent an
   absolute timestamp: AFSAbsTime64 and AFSAbsTime64Res. The only
   difference between these two types is that AFSAbsTime64Res includes
   resolution information, and AFSAbsTime64 does not.  This section
   serves to guide designers of future AFS-3 RPCs in what circumstances
   each type should be used.




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   When deciding whether to use AFSAbsTime64 or AFSAbsTime64Res in a
   structure field or RPC argument, the first determination that must be
   made is whether the timestamp value will or could ever be used to
   make ordering decisions by an AFS-3 service.  If it will or could,
   then the argument or field should be of the AFSAbsTime64Res type.

   Otherwise, the determination should be made whether or not any
   service (possibly unrelated to AFS-3) may realistically make ordering
   decisions based on the field or argument.  If it may, then the
   AFSAbsTime64Res type should be considered; otherwise, the
   AFSAbsTime64 type should be used.

   For example, as mentioned in Section 4.2, the AFS-3 Volume Service
   and clients make ordering decisions based on timestamps related to
   when volume operations have occurred.  So, timestamp fields related
   to volume operations should probably use the AFSAbsTime64Res type.

   However, when a timestamp is used to represent the modification time
   of a file in AFS, that timestamp is not used by AFS-3 services to
   make any ordering decisions.  While it is possible that some software
   unrelated to AFS-3 may try to make ordering decisions based off of
   that timestamp, it is unlikely to be able to do so reliably.  This is
   because file modification timestamps can usually be set to any time
   by humans, and any time resolution information stored is usually not
   available to programs that are not AFS-3-aware.  And in general,
   AFS-3 file metadata is not intended to be a general-purpose
   distributed synchronization mechanism.  So, file modification
   timestamps should probably use the AFSAbsTime64 type.


5.  Resolution Limitations

   The types specified in this document are limited to 100-nanosecond
   resolution or coarser.  There are other systems which may interact
   with AFS-3 that have finer resolution; for example, the NFSv4
   nfstime4 structure in Section 2.2 of [RFC3530] and the timespec
   structure in [POSIX] both allow for timestamps with a resolution of
   1-ns.  Because of this, there are inherent problems with interacting
   with such systems.

   It is believed that for a large majority of use cases, timestamps
   with resolution finer than 100-nanoseconds are not necessary, and so
   the types defined in this document should be sufficient.  However,
   there may be use cases in which resolution finer than 100-ns is
   required.  In addition, there are also several use cases where the
   legacy 32-bit timestamps are adequate, and the additional space
   overhead of the types defined by this document may be considered
   unnecessary overhead.



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   This document does not accommodate for those cases, but this document
   does not restrict AFS-3 to only use the time types defined in this
   document.  It is recommended that future AFS-3 RPCs are designed such
   that they make take advantage of several different time types of
   varying resolutions, so that such use cases can be accommodated while
   not sacrificing the space efficiency for the common case addressed by
   the time types defined in this document.  Any such method of
   accommodating for different time types are left up to the individual
   RPCs or wire structures, and are not discussed here.


6.  Times Before UTC

   The absolute time types defined in this document are specified as
   relative to midnight January 1, 1970 UTC, excluding leap seconds, and
   times far earlier than that are also representable.  It is worthy to
   note that UTC did not exist until January 1, 1972, and so times
   before 1972 specified as UTC are technically meaningless.  However,
   it is convenient to assume that UTC has existed for all eternity.
   For all times before 1972, we represent time as if UTC has always
   existed, using the obvious backwards projection of the current UTC
   time zone and Gregorian calendar rules.


7.  Converting Time Types

   In general, when converting an AFSAbsTime64 or AFSAbsTime64Res value
   to some other type that has granularity coarser than 100 ns
   granularity, the resulting value MUST always be rounded down to the
   nearest lower increment of the resultant type.  When converting to
   the POSIX time_t type, for example, the AFSAbsTime or AFSAbsTime64Res
   value MUST be rounded down to the nearest lower second.  When
   converting to the POSIX struct timeval type, the value MUST be
   rounded down to the nearest lower microsecond.

   When converting to or from the Microsoft FILETIME format, a constant
   value must be added or subtracted, since FILETIME specifies time
   relative to midnight 1 January 1601 UTC, but AFSAbsTime64 and
   AFSAbsTime64Res specify time relative to midnight 1 January 1970 UTC.
   When converting from an AFSAbsTime64 to a Microsoft FILETIME, the
   value 116444736000000000 must be subtracted from the AFSAbsTime64
   value.  When converting to an AFSAbsTime64 from a Microsoft FILETIME,
   the value 116444736000000000 must be added to the FILETIME value.

   It is also important to keep in mind that when converting from
   AFSAbsTime64Res to time_t or FILETIME types, strictly speaking the
   AFSAbsTime64Res structure represents two times: the beginning and end
   time.  So it is impossible to accurately convert an AFSAbsTime64Res



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   structure to a single time value.  This is often unavoidable when
   converting to legacy AFS-3 interfaces, or interfaces unrelated to
   AFS-3, however, and when only one time value is given to convert to,
   implementations MUST specify the beginning time (that is, the time
   represented by the timestamp field).

7.1.  Special Cases

   Extant AFS-3 RPCs often use a timestamp of 0 to represent a special
   meaning.  That is, a timestamp of 0 often does not indicate midnight
   1 January 1970 UTC, but may represent a logical value of "negative
   infinity", or indicates some special meaning that is specific to that
   RPC.  The value of 0 was often just used because it is the earliest
   representable time for a 32-bit unsigned integer.

   Any such special meanings must be specified by the RPC in question,
   and this document assigns no special meaning to the value of 0 for
   any of the types defined in this document.  However, this document
   recommends that any future RPCs keep the special meaning of the 0
   timestamp, if the RPC is replacing an RPC that previously had a
   special meaning for timestamp 0, even though that is no longer the
   earliest representable time.  If the new RPC uses an AFSAbsTime64Res
   argument, the resolution field should be 0, as well.

   For example, say there is an AFS-3 RPC called AFSFoo that accepts an
   afs_uint32 absolute timestamp argument, and it specifies that a
   timestamp of 0 represents some special case.  Let another RPC,
   AFSFoo64, define an RPC that is identical to AFSFoo except that it
   accepts an AFSAbsTime64Res parameter.  AFSFoo64 should specify that a
   caller should specify an AFSAbsTime64Res with timestamp 0, resolution
   0, to indicate the special case previously indicated by giving a 32-
   bit timestamp of 0.

7.2.  Sample Code

   Sample C code is provided here to convert AFSAbsTime64, AFSRelTime64,
   and AFSAbsTime64Res values to and from FILETIME and POSIX time_t
   values where appropriate.  Also provided is a function to compare two
   AFSAbsTime64Res values, and functions to add an AFSRelTime64 to an
   AFSAbsTime64Res and AFSAbsTime64.

   The conversion functions follow the recommendations in Section 7.1.
   So, a time_t with the value of 0 will be converted to an AFSAbsTime
   with the value of 0, or an AFSAbsTime64Res value of timestamp 0,
   resolution 0.  AFSAbsTime64Res structures with a resolution of 0 (and
   a non-zero timestamp) are treated as having an effective resolution
   of 1 second, as suggested in Section 3.3.1.




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   These functions do not handle overflow, underflow, or other errors,
   and are just guidelines for the general conversion algorithms.

  #define AFSTIME64_WINNT_SHIFT 116444736000000000ULL
  #define AFSTIME64_POSIX_SCALE 10000000U
  #define AFSTIME64_DEFAULT_RES 10000000U

  void
  timet_to_AFSAbsTime64(time_t t, AFSAbsTime64 *atsp)
  {
      *atsp = (t * AFSTIME64_POSIX_SCALE);
  }
  void
  AFSAbsTime64_to_timet(AFSAbsTime64 ats, time_t *tp)
  {
      *tp = (ats / AFSTIME64_POSIX_SCALE);
  }
  void
  timet_to_AFSRelTime64(time_t t, AFSRelTime64 *artsp)
  {
      *artsp = (t * AFSTIME64_POSIX_SCALE);
  }
  void
  AFSRelTime64_to_timet(AFSRelTime64 arts, time_t *tp)
  {
      *tp = (arts / AFSTIME64_POSIX_SCALE);
  }
  void
  timet_to_AFSAbsTime64Res(time_t t, AFSAbsTime64Res *atp)
  {
      timet_to_AFSAbsTime64(t, &atp->timestamp);
      if (t == 0) {
          atp->resolution = 0;
      } else {
          atp->resolution = AFSTIME64_POSIX_SCALE;
      }
  }
  void
  AFSAbsTime64Res_to_timet(AFSAbsTime64Res *atp, time_t *t1, time_t *t2)
  {
      unsigned int res = atp->resolution;
      if (res == 0) {
          res = AFSTIME64_DEFAULT_RES;
      }
      AFSAbsTime64_to_timet(atp->timestamp, t1);
      AFSAbsTime64_to_timet(atp->timestamp + res, t2);
  }
  void



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  FILETIME_to_AFSAbsTime64(FILETIME *ftp, AFSAbsTime64 *atsp)
  {
      ULARGE_INTEGER uli;
      uli.LowPart = ftp->dwLowDateTime;
      uli.HighPart = ftp->dwHighDateTime;
      *atsp = uli.QuadPart - AFSTIME64_WINNT_SHIFT;
  }
  void
  AFSAbsTime64_to_FILETIME(AFSAbsTime64 ats, FILETIME *ftp)
  {
      ULARGE_INTEGER uli;
      uli.QuadPart = ats + AFSTIM64_WINNT_SHIFT;
      ftp->dwLowDateTime = uli.LowPart;
      ftp->dwHighDateTime = uli.HighPart;
  }
  void
  AFSAbsTime64Res_to_FILETIME(AFSAbsTime64Res *atp, FILETIME *ft1,
                              FILETIME *ft2)
  {
      unsigned int res = atp->resolution;
      if (res == 0) {
          res = AFSTIME64_DEFAULT_RES;
      }
      AFSAbsTime64_to_FILEMTIME(atp->timestamp, ft1);
      AFSAbsTime64_to_FILEMTIME(atp->timestamp + res, ft2);
  }
  void
  AFSAbsTime64Res_add_AFSRelTime64(AFSAbsTime64Res *atp,
                                   AFSRelTime64 arts)
  {
      atp->timestamp += arts;
  }
  void
  AFSAbsTime64_add_AFSRelTime64(AFSAbsTime *atsp,
                                AFSRelTime arts)
  {
      *atsp += arts;
  }
  int
  cmp_AFSAbsTime64Res(AFSAbsTime64Res *atp1, AFSAbsTime64Res *atp2)
  {
      unsigned int res1 = atp1->resolution;
      unsigned int res2 = atp2->resolution;
      if (res1 == 0) {
          res1 = AFSTIME64_DEFAULT_RES;
      }
      if (res2 == 0) {
          res2 = AFSTIME64_DEFAULT_RES;



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      }
      if (atp1->timestamp + res1 <= atp2->timestamp) {
          return -1;
      }
      if (atp2->timestamp + res2 <= atp1->timestamp) {
          return 1;
      }
      return 0;
  }


8.  Security Considerations

   This memo raises no security issues.


9.  IANA Considerations

   This document makes no request of the IANA.


10.  Acknowledgements

   The author thanks Simon Wilkinson and Jeffrey Altman for some
   background text, Jeffrey Altman, David Boyes, Tom Keiser, and Simon
   Wilkinson for discussion on the problem of time resolution, Steven
   Jenkins for discussion on interoperability concerns, Russ Allbery for
   input on UTC, leap seconds, and dates before 1970, and the general
   membership of the afs3-standardization@openafs.org mailing list for
   general discussion on the balance between time granularity and field
   width overhead.


11.  References

11.1.  Normative References

   [RFC2119]  Bradner, S., "Key words for use in RFCs to Indicate
              Requirement Levels", BCP 14, RFC 2119, March 1997.

11.2.  Informative References

   [POSIX]    Institute of Electrical and Electronics Engineers, "IEEE
              Standard for Information Technology - Portable Operating
              System Interface (POSIX) Base Specifications, Issue 7",
              IEEE Std 1003.1-2008, 2008.

   [RFC3530]  Shepler, S., Callaghan, B., Robinson, D., Thurlow, R.,



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Internet-Draft            AFS-3 Base Time Types              August 2011


              Beame, C., Eisler, M., and D. Noveck, "Network File System
              (NFS) version 4 Protocol", RFC 3530, April 2003.

   [RFC4506]  Eisler, M., "XDR: External Data Representation Standard",
              STD 67, RFC 4506, May 2006.


Author's Address

   Andrew Deason
   Sine Nomine Associates
   43596 Blacksmith Square
   Ashburn, Virginia  20147-4606
   USA

   Phone: +1 703 723 6673
   Email: adeason@sinenomine.net


































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