New paragraph "Reproducibility considerations" moved out of ENVIRONMENT

xorriso/xorriso.1

@@ -9,7 +9,7 @@
 .\" First parameter, NAME, should be all caps
 .\" Second parameter, SECTION, should be 1-8, maybe w/ subsection
 .\" other parameters are allowed: see man(7), man(1)
-.TH XORRISO 1 "Version 1.5.7, Apr 24, 2025"
+.TH XORRISO 1 "Version 1.5.7, Jun 10, 2025"
 .\" Please adjust this date whenever revising the manpage.
 .\"
 .\" Some roff macros, for reference:
@@ -6582,6 +6582,53 @@ Use text as name of this program in subsequent messages
 .TP
 \fB\-prog_help\fR text
 Use text as name of this program and perform \-help.
+.TP
+.B Reproducibility considerations:
+.PP
+Stable versions of xorriso are prepared to produce in repeated runs from
+the same input files with the same file metadata and the same xorriso commands
+the same ISO 9660 filesystem bytes. The only exception are bytes which depend
+on the current time of the xorriso run.
+.br
+These time dependent values can be set to fixed values by the commands
+\-volume_date "uuid", \-boot_image "any" "gpt_disk_guid=",
+\-volume_date "all_file_dates", and \-iso_nowtime. Instead of setting each of
+them, it is possible to influence them all by the environment variable
+SOURCE_DATE_EPOCH.
+.br
+SOURCE_DATE_EPOCH belongs to the specification of reproducible\-builds.org.
+It is supposed to be either undefined or to contain a decimal number
+which tells the seconds since january 1st 1970. If it contains a number,
+then it is used as time value to set the default of
+\-volume date "uuid", sets \-boot_image "any" "gpt_disk_guid=" to
+"volume_date_uuid", \-volume_date "all_file_dates" to "set_to_mtime",
+and \-iso_nowtime.
+.br
+Startup files and xorriso commands can override the effect of
+SOURCE_DATE_EPOCH.
+.PP
+Different versions of xorriso may or may not produce the same result from
+the same input and commands. Reproducibility may be prevented by bug fixes
+or feature enhancements between versions.
+.br
+xorriso puts its version information into the Preparer Id field of the
+ISO 9660 Primary Volume Descriptor by default. This may be desired in order
+to clearly define which xorriso version has to be used for reproduction.
+But it may also be undesired because a wider range of xorriso versions shall
+not be excluded from an attempt of reproduction.
+.br
+Use command \-preparer_id with a text other than "@xorriso@" if you want to
+override the default at first production time. This command may also be used
+to explicitly set the preparer id as found in an ISO 9660 filesystem which
+shall be reproduced by a different version of xorriso. The preparer id can be
+inquired by command \-pvd_info.
+.PP
+If reproducibility of xorriso results is desired, then the precautions \- like
+setting SOURCE_DATE_EPOCH \- should be done already with the original xorriso
+run. All input files, the used xorriso commands in exact sequence, the version
+of xorriso, and the possibly set SOURCE_DATE_EPOCH value should then be kept
+or recorded for later re\-use.
+.br
 .br
 .SH EXAMPLES
 .SS
@@ -7156,27 +7203,7 @@ The following environment variables influence the program behavior:
 HOME is used to find startup files of xorriso and mkisofs.
 .br
 SOURCE_DATE_EPOCH belongs to the specs of reproducible\-builds.org.
-It is supposed to be either undefined or to contain a decimal number
+See above paragraph "Reproducibility considerations".
-which tells the seconds since january 1st 1970. If it contains a number,
-then it is used as time value to set the default of
-\-volume date "uuid", sets \-boot_image "any" "gpt_disk_guid=" to
-"volume_date_uuid", \-volume_date "all_file_dates" to "set_to_mtime",
-and \-iso_nowtime to "=$SOURCE_DATE_EPOCH".
-.br
-Startup files and program commands can override the effect of
-SOURCE_DATE_EPOCH.
-.br
-Be aware that by default xorriso puts its version information into the
-Preparer Id field of the ISO 9660 Primary Volume Descriptor. This may be
-desired in order to clearly define which xorriso version has to be used for
-reproduction. But it may also be undesired because a wider range of xorriso
-versions shall not be excluded from an attempt of reproduction.
-.br
-Use command \-preparer_id with a text other than "@xorriso@" if you want to
-override the default at first production time. This command may also be used
-to explicitly set the preparer id as found in an ISO 9660 filesystem which
-shall be reproduced by a different version of xorriso. The id can be inquired
-by command \-pvd_info.
 .br
 .SS
 .SH SEE ALSO

xorriso/xorriso.info

@@ -595,6 +595,7 @@ inner dashes are interpreted as underscores.
 * Emulation::           Command compatibility emulations (cdrtools)
 * Scripting::           Scripting, dialog and program control features
 * Frontend::            Support for frontend programs via stdin and stdout
+* Reproducible::        Reproducibility considerations
 
 
 File: xorriso.info,  Node: ArgSort,  Next: AqDrive,  Prev: Commands,  Up: Commands
@@ -5330,7 +5331,7 @@ File: xorriso.info,  Node: Scripting,  Next: Frontend,  Prev: Emulation,  Up: Co
      readline history.
 
 
-File: xorriso.info,  Node: Frontend,  Next: ExDevices,  Prev: Scripting,  Up: Commands
+File: xorriso.info,  Node: Frontend,  Next: Reproducible,  Prev: Scripting,  Up: Commands
 
 9.22 Support for frontend programs via stdin and stdout
 =======================================================
@@ -5509,6 +5510,52 @@ File: xorriso.info,  Node: Frontend,  Next: ExDevices,  Prev: Scripting,  Up: Co
 -prog_help text
      Use text as name of this program and perform -help.
 
+
+File: xorriso.info,  Node: Reproducible,  Next: Examples,  Prev: Frontend,  Up: Commands
+
+9.23 Reproducibility considerations
+===================================
+
+Stable versions of xorriso are prepared to produce in repeated runs from
+the same input files with the same file metadata and the same xorriso
+commands the same ISO 9660 filesystem bytes.  The only exception are
+bytes which depend on the current time of the xorriso run.
+These time dependent values can be set to fixed values by the commands
+-volume_date "uuid", -boot_image "any" "gpt_disk_guid=", -volume_date
+"all_file_dates", and -iso_nowtime.  Instead of setting each of them, it
+is possible to influence them all by the environment variable
+SOURCE_DATE_EPOCH.
+SOURCE_DATE_EPOCH belongs to the specification of
+reproducible-builds.org.  It is supposed to be either undefined or to
+contain a decimal number which tells the seconds since january 1st 1970.
+If it contains a number, then it is used as time value to set the
+default of -volume date "uuid", sets -boot_image "any" "gpt_disk_guid="
+to "volume_date_uuid", -volume_date "all_file_dates" to "set_to_mtime",
+and -iso_nowtime.
+Startup files and xorriso commands can override the effect of
+SOURCE_DATE_EPOCH.
+
+   Different versions of xorriso may or may not produce the same result
+from the same input and commands.  Reproducibility may be prevented by
+bug fixes or feature enhancements between versions.
+xorriso puts its version information into the Preparer Id field of the
+ISO 9660 Primary Volume Descriptor by default.  This may be desired in
+order to clearly define which xorriso version has to be used for
+reproduction.  But it may also be undesired because a wider range of
+xorriso versions shall not be excluded from an attempt of reproduction.
+Use command -preparer_id with a text other than "@xorriso@" if you want
+to override the default at first production time.  This command may also
+be used to explicitly set the preparer id as found in an ISO 9660
+filesystem which shall be reproduced by a different version of xorriso.
+The preparer id can be inquired by command -pvd_info.
+
+   If reproducibility of xorriso results is desired, then the
+precautions - like setting SOURCE_DATE_EPOCH - should be done already
+with the original xorriso run.  All input files, the used xorriso
+commands in exact sequence, the version of xorriso, and the possibly set
+SOURCE_DATE_EPOCH value should then be kept or recorded for later
+re-use.
+
 
 File: xorriso.info,  Node: Examples,  Next: Files,  Prev: Commands,  Up: Top
 
@@ -6048,26 +6095,8 @@ File: xorriso.info,  Node: Environ,  Next: Seealso,  Prev: Files,  Up: Top
 
 The following environment variables influence the program behavior:
 HOME is used to find startup files of xorriso and mkisofs.
-SOURCE_DATE_EPOCH belongs to the specs of reproducible-builds.org.  It
+SOURCE_DATE_EPOCH belongs to the specs of reproducible-builds.org.  See
-is supposed to be either undefined or to contain a decimal number which
+above paragraph "Reproducibility considerations".
-tells the seconds since january 1st 1970.  If it contains a number, then
-it is used as time value to set the default of -volume date "uuid", sets
--boot_image "any" "gpt_disk_guid=" to "volume_date_uuid", -volume_date
-"all_file_dates" to "set_to_mtime", and -iso_nowtime to
-"=$SOURCE_DATE_EPOCH".
-Startup files and program commands can override the effect of
-SOURCE_DATE_EPOCH.
-Be aware that by default xorriso puts its version information into the
-Preparer Id field of the ISO 9660 Primary Volume Descriptor.  This may
-be desired in order to clearly define which xorriso version has to be
-used for reproduction.  But it may also be undesired because a wider
-range of xorriso versions shall not be excluded from an attempt of
-reproduction.
-Use command -preparer_id with a text other than "@xorriso@" if you want
-to override the default at first production time.  This command may also
-be used to explicitly set the preparer id as found in an ISO 9660
-filesystem which shall be reproduced by a different version of xorriso.
-The id can be inquired by command -pvd_info.
 
 
 File: xorriso.info,  Node: Seealso,  Next: Bugreport,  Prev: Environ,  Up: Top
@@ -6783,51 +6812,52 @@ Node: Extras15805
 Node: Processing21907
 Node: Dialog25744
 Node: Commands27433
-Node: ArgSort29110
+Node: ArgSort29165
-Node: AqDrive30604
+Node: AqDrive30659
-Node: Loading37784
+Node: Loading37839
-Node: Insert68537
+Node: Insert68592
-Node: SetInsert80732
+Node: SetInsert80787
-Node: Manip90968
+Node: Manip91023
-Node: CmdFind103464
+Node: CmdFind103519
-Node: Filter125324
+Node: Filter125379
-Node: Writing129946
+Node: Writing130001
-Node: SetWrite142440
+Node: SetWrite142495
-Node: Bootable173872
+Node: Bootable173927
-Node: Jigdo206606
+Node: Jigdo206661
-Node: Charset211609
+Node: Charset211664
-Node: Exception214938
+Node: Exception214993
-Node: DialogCtl221127
+Node: DialogCtl221182
-Node: Inquiry223729
+Node: Inquiry223784
-Node: Navigate236424
+Node: Navigate236479
-Node: Verify248477
+Node: Verify248532
-Node: Restore259626
+Node: Restore259681
-Node: Emulation271833
+Node: Emulation271888
-Node: Scripting283409
+Node: Scripting283464
-Node: Frontend291664
+Node: Frontend291719
-Node: Examples301290
+Node: Reproducible301348
-Node: ExDevices302468
+Node: Examples303809
-Node: ExCreate303129
+Node: ExDevices304987
-Node: ExDialog304429
+Node: ExCreate305648
-Node: ExGrowing305700
+Node: ExDialog306948
-Node: ExModifying306509
+Node: ExGrowing308219
-Node: ExBootable307019
+Node: ExModifying309028
-Node: ExCharset307574
+Node: ExBootable309538
-Node: ExPseudo308470
+Node: ExCharset310093
-Node: ExCdrecord309397
+Node: ExPseudo310989
-Node: ExMkisofs309717
+Node: ExCdrecord311916
-Node: ExGrowisofs311614
+Node: ExMkisofs312236
-Node: ExException312767
+Node: ExGrowisofs314133
-Node: ExTime313225
+Node: ExException315286
-Node: ExIncBackup313683
+Node: ExTime315744
-Node: ExRestore317709
+Node: ExIncBackup316202
-Node: ExRecovery318655
+Node: ExRestore320228
-Node: Files319227
+Node: ExRecovery321174
-Node: Environ320561
+Node: Files321746
-Node: Seealso322000
+Node: Environ323080
-Node: Bugreport322800
+Node: Seealso323431
-Node: Legal323391
+Node: Bugreport324231
-Node: CommandIdx324403
+Node: Legal324822
-Node: ConceptIdx343709
+Node: CommandIdx325834
+Node: ConceptIdx345140
 
 End Tag Table

xorriso/xorriso.texi

@@ -50,7 +50,7 @@
 @c man .\" First parameter, NAME, should be all caps
 @c man .\" Second parameter, SECTION, should be 1-8, maybe w/ subsection
 @c man .\" other parameters are allowed: see man(7), man(1)
-@c man .TH XORRISO 1 "Version 1.5.7, Apr 24, 2025"
+@c man .TH XORRISO 1 "Version 1.5.7, Jun 10, 2025"
 @c man .\" Please adjust this date whenever revising the manpage.
 @c man .\"
 @c man .\" Some roff macros, for reference:
@@ -844,6 +844,7 @@ inner dashes are interpreted as underscores.
 * Emulation::           Command compatibility emulations (cdrtools)
 * Scripting::           Scripting, dialog and program control features
 * Frontend::            Support for frontend programs via stdin and stdout
+* Reproducible::        Reproducibility considerations
 @end menu
 @c man .TP
 @node ArgSort, AqDrive, Commands, Commands
@@ -7227,7 +7228,7 @@ Do not execute the line but store it in readline history.
 @end table
 @c man .TP
 @c man .B Support for frontend programs via stdin and stdout:
-@node Frontend, ExDevices, Scripting, Commands
+@node Frontend, Reproducible, Scripting, Commands
 @section Support for frontend programs via stdin and stdout
 @table @asis
 @c man .TP
@@ -7479,6 +7480,57 @@ Use text as name of this program in subsequent messages
 @cindex Program, print help text, -prog_help
 Use text as name of this program and perform -help.
 @end table
+@c man .TP
+@c man .B Reproducibility considerations:
+@node Reproducible, Examples, Frontend, Commands
+@section Reproducibility considerations
+@c man .PP
+Stable versions of xorriso are prepared to produce in repeated runs from
+the same input files with the same file metadata and the same xorriso commands
+the same ISO 9660 filesystem bytes. The only exception are bytes which depend
+on the current time of the xorriso run.
+@*
+These time dependent values can be set to fixed values by the commands
+-volume_date "uuid", -boot_image "any" "gpt_disk_guid=",
+-volume_date "all_file_dates", and -iso_nowtime. Instead of setting each of
+them, it is possible to influence them all by the environment variable
+SOURCE_DATE_EPOCH.
+@*
+SOURCE_DATE_EPOCH belongs to the specification of reproducible-builds.org.
+It is supposed to be either undefined or to contain a decimal number
+which tells the seconds since january 1st 1970. If it contains a number,
+then it is used as time value to set the default of
+-volume date "uuid", sets -boot_image "any" "gpt_disk_guid=" to
+"volume_date_uuid", -volume_date "all_file_dates" to "set_to_mtime",
+and -iso_nowtime.
+@*
+Startup files and xorriso commands can override the effect of
+SOURCE_DATE_EPOCH.
+@c man .PP
+@sp 1
+Different versions of xorriso may or may not produce the same result from
+the same input and commands. Reproducibility may be prevented by bug fixes
+or feature enhancements between versions.
+@*
+xorriso puts its version information into the Preparer Id field of the
+ISO 9660 Primary Volume Descriptor by default. This may be desired in order
+to clearly define which xorriso version has to be used for reproduction.
+But it may also be undesired because a wider range of xorriso versions shall
+not be excluded from an attempt of reproduction.
+@*
+Use command -preparer_id with a text other than "@@xorriso@@" if you want to
+override the default at first production time. This command may also be used
+to explicitly set the preparer id as found in an ISO 9660 filesystem which
+shall be reproduced by a different version of xorriso. The preparer id can be
+inquired by command -pvd_info.
+@c man .PP
+@sp 1
+If reproducibility of xorriso results is desired, then the precautions - like
+setting SOURCE_DATE_EPOCH - should be done already with the original xorriso
+run. All input files, the used xorriso commands in exact sequence, the version
+of xorriso, and the possibly set SOURCE_DATE_EPOCH value should then be kept
+or recorded for later re-use.
+@*
 @c man .br
 @node Examples, Files, Commands, Top
 @chapter Examples
@@ -8215,27 +8267,7 @@ The following environment variables influence the program behavior:
 HOME is used to find startup files of xorriso and mkisofs.
 @*
 SOURCE_DATE_EPOCH belongs to the specs of reproducible-builds.org.
-It is supposed to be either undefined or to contain a decimal number
+See above paragraph "Reproducibility considerations".
-which tells the seconds since january 1st 1970. If it contains a number,
-then it is used as time value to set the default of
--volume date "uuid", sets -boot_image "any" "gpt_disk_guid=" to
-"volume_date_uuid", -volume_date "all_file_dates" to "set_to_mtime",
-and -iso_nowtime to "=$SOURCE_DATE_EPOCH".
-@*
-Startup files and program commands can override the effect of
-SOURCE_DATE_EPOCH.
-@*
-Be aware that by default xorriso puts its version information into the
-Preparer Id field of the ISO 9660 Primary Volume Descriptor. This may be
-desired in order to clearly define which xorriso version has to be used for
-reproduction. But it may also be undesired because a wider range of xorriso
-versions shall not be excluded from an attempt of reproduction.
-@*
-Use command -preparer_id with a text other than "@@xorriso@@" if you want to
-override the default at first production time. This command may also be used
-to explicitly set the preparer id as found in an ISO 9660 filesystem which
-shall be reproduced by a different version of xorriso. The id can be inquired
-by command -pvd_info.
 @*
 @sp 1
 @c man .SS

xorriso/xorrisofs.1

@@ -9,7 +9,7 @@
 .\" First parameter, NAME, should be all caps
 .\" Second parameter, SECTION, should be 1-8, maybe w/ subsection
 .\" other parameters are allowed: see man(7), man(1)
-.TH XORRISOFS 1 "Version 1.5.7, Apr 24, 2025"
+.TH XORRISOFS 1 "Version 1.5.7, Jun 10, 2025"
 .\" Please adjust this date whenever revising the manpage.
 .\"
 .\" Some roff macros, for reference:
@@ -1835,6 +1835,54 @@ Print to standard output a text that begins with
  "mkisofs 2.01\-Emulation Copyright (C)"
 .br
 and to standard error the version information of xorriso.
+.TP
+.B Reproducibility considerations:
+.PP
+Stable versions of xorriso are prepared to produce in repeated runs from
+the same input files with the same file metadata and the same xorrisofs options
+the same ISO 9660 filesystem bytes. The only exception are bytes which depend
+on the current time of the xorriso run.
+.br
+These time dependent values can be set to fixed values by the options
+\-\-modification\-date=, \-\-gpt_disk_guid, and
+\-\-set_all_file_dates. Instead of setting each of
+them, it is possible to influence them all by the environment variable
+SOURCE_DATE_EPOCH.
+.br
+SOURCE_DATE_EPOCH belongs to the specification of reproducible\-builds.org.
+It is supposed to be either undefined or to contain a decimal number
+which tells the seconds since january 1st 1970. If it contains a number,
+then it is used as time value to set the default of
+\-\-modification\-date=. \-\-gpt_disk_guid defaults
+to "modification\-date". The default of \-\-set_all_file_dates
+is then "set_to_mtime". Further the "now" time for ISO nodes without disk
+source is set to the SOURCE_DATE_EPOCH value.
+.br
+Startup files and xorrisofs options can override the effect of
+SOURCE_DATE_EPOCH.
+.PP
+Different versions of xorriso may or may not produce the same result from
+the same input and options. Reproducibility may be prevented by bug fixes
+or feature enhancements between versions.
+.br
+xorriso puts its version information into the Preparer Id field of the
+ISO 9660 Primary Volume Descriptor by default. This may be desired in order
+to clearly define which xorriso version has to be used for reproduction.
+But it may also be undesired because a wider range of xorriso versions shall
+not be excluded from an attempt of reproduction.
+.br
+Use option \-p with a text other than "@xorriso@" if you want to
+override the default at first production time. This option may also be used
+to explicitly set the preparer id as found in an ISO 9660 filesystem which
+shall be reproduced by a different version of xorriso. The preparer id can be
+inquired by xorriso command \-pvd_info.
+.PP
+If reproducibility of xorrisofs results is desired, then the precautions \- like
+setting SOURCE_DATE_EPOCH \- should be done already with the original xorrisofs
+run. All input files, the used xorrisofs options in exact sequence, the version
+of xorriso, and the possibly set SOURCE_DATE_EPOCH value should then be kept
+or recorded for later re\-use.
+.br
 .br
 .SH EXAMPLES
 .SS
@@ -2308,30 +2356,8 @@ HOME is used to find xorriso and mkisofs startup files.
 .br
 MKISOFSRC may be used to point the program to a mkisofs startup file.
 .br
-.sp 1
 SOURCE_DATE_EPOCH belongs to the specs of reproducible\-builds.org.
-It is supposed to be either undefined or to contain a decimal number
+See above paragraph "Reproducibility considerations".
-which tells the seconds since january 1st 1970. If it contains a number,
-then it is used as time value to set the default of
-\-\-modification\-date=.
-\-\-gpt_disk_guid defaults to "modification\-date".
-The default of \-\-set_all_file_dates is then "set_to_mtime".
-Further the "now" time for ISO nodes without disk source is then set to
-the SOURCE_DATE_EPOCH value.
-.br
-Startup files and program options can override the effect of SOURCE_DATE_EPOCH.
-.br
-Be aware that by default xorriso puts its version information into the
-Preparer Id field of the ISO 9660 Primary Volume Descriptor. This may be
-desired in order to clearly define which xorriso version has to be used for
-reproduction. But it may also be undesired because a wider range of xorriso
-versions shall not be excluded from an attempt of reproduction.
-.br
-Use option \-p with a text other than "@xorriso@" if you want to
-override the default at first production time. This option may also be used
-to explicitly set the preparer id as found in an ISO 9660 filesystem which 
-shall be reproduced by a different version of xorriso. The id can be inquired
-by the generic xorriso command \-pvd_info.
 .br
 .SS 
 .SH SEE ALSO

xorriso/xorrisofs.info

@@ -173,6 +173,7 @@ File: xorrisofs.info,  Node: Options,  Next: Examples,  Prev: Xorriso,  Up: Top
 * Charset::             Character sets
 * Jigdo::               Jigdo Template Extraction
 * Miscellaneous::       Miscellaneous options
+* Reproducible::        Reproducibility considerations
 
 
 File: xorrisofs.info,  Node: Loading,  Next: SetInsert,  Prev: Options,  Up: Options
@@ -1530,7 +1531,7 @@ counted as part of the ISO image.
      -checksum_algorithm_iso.
 
 
-File: xorrisofs.info,  Node: Miscellaneous,  Next: ExSimple,  Prev: Jigdo,  Up: Options
+File: xorrisofs.info,  Node: Miscellaneous,  Next: Reproducible,  Prev: Jigdo,  Up: Options
 
 5.12 Miscellaneous options
 ==========================
@@ -1591,6 +1592,52 @@ File: xorrisofs.info,  Node: Miscellaneous,  Next: ExSimple,  Prev: Jigdo,  Up:
      "mkisofs 2.01-Emulation Copyright (C)"
      and to standard error the version information of xorriso.
 
+
+File: xorrisofs.info,  Node: Reproducible,  Next: Examples,  Prev: Miscellaneous,  Up: Options
+
+5.13 Reproducibility considerations
+===================================
+
+Stable versions of xorriso are prepared to produce in repeated runs from
+the same input files with the same file metadata and the same xorrisofs
+options the same ISO 9660 filesystem bytes.  The only exception are
+bytes which depend on the current time of the xorriso run.
+These time dependent values can be set to fixed values by the options
+--modification-date=, --gpt_disk_guid, and --set_all_file_dates.
+Instead of setting each of them, it is possible to influence them all by
+the environment variable SOURCE_DATE_EPOCH.
+SOURCE_DATE_EPOCH belongs to the specification of
+reproducible-builds.org.  It is supposed to be either undefined or to
+contain a decimal number which tells the seconds since january 1st 1970.
+If it contains a number, then it is used as time value to set the
+default of --modification-date=.  --gpt_disk_guid defaults to
+"modification-date".  The default of --set_all_file_dates is then
+"set_to_mtime".  Further the "now" time for ISO nodes without disk
+source is set to the SOURCE_DATE_EPOCH value.
+Startup files and xorrisofs options can override the effect of
+SOURCE_DATE_EPOCH.
+
+   Different versions of xorriso may or may not produce the same result
+from the same input and options.  Reproducibility may be prevented by
+bug fixes or feature enhancements between versions.
+xorriso puts its version information into the Preparer Id field of the
+ISO 9660 Primary Volume Descriptor by default.  This may be desired in
+order to clearly define which xorriso version has to be used for
+reproduction.  But it may also be undesired because a wider range of
+xorriso versions shall not be excluded from an attempt of reproduction.
+Use option -p with a text other than "@xorriso@" if you want to override
+the default at first production time.  This option may also be used to
+explicitly set the preparer id as found in an ISO 9660 filesystem which
+shall be reproduced by a different version of xorriso.  The preparer id
+can be inquired by xorriso command -pvd_info.
+
+   If reproducibility of xorrisofs results is desired, then the
+precautions - like setting SOURCE_DATE_EPOCH - should be done already
+with the original xorrisofs run.  All input files, the used xorrisofs
+options in exact sequence, the version of xorriso, and the possibly set
+SOURCE_DATE_EPOCH value should then be kept or recorded for later
+re-use.
+
 
 File: xorrisofs.info,  Node: Examples,  Next: Files,  Prev: Options,  Up: Top
 
@@ -2010,28 +2057,8 @@ File: xorrisofs.info,  Node: Environ,  Next: Seealso,  Prev: Files,  Up: Top
 The following environment variables influence the program behavior:
 HOME is used to find xorriso and mkisofs startup files.
 MKISOFSRC may be used to point the program to a mkisofs startup file.
-
+SOURCE_DATE_EPOCH belongs to the specs of reproducible-builds.org.  See
-   SOURCE_DATE_EPOCH belongs to the specs of reproducible-builds.org.
+above paragraph "Reproducibility considerations".
-It is supposed to be either undefined or to contain a decimal number
-which tells the seconds since january 1st 1970.  If it contains a
-number, then it is used as time value to set the default of
---modification-date=.  --gpt_disk_guid defaults to "modification-date".
-The default of --set_all_file_dates is then "set_to_mtime".  Further the
-"now" time for ISO nodes without disk source is then set to the
-SOURCE_DATE_EPOCH value.
-Startup files and program options can override the effect of
-SOURCE_DATE_EPOCH.
-Be aware that by default xorriso puts its version information into the
-Preparer Id field of the ISO 9660 Primary Volume Descriptor.  This may
-be desired in order to clearly define which xorriso version has to be
-used for reproduction.  But it may also be undesired because a wider
-range of xorriso versions shall not be excluded from an attempt of
-reproduction.
-Use option -p with a text other than "@xorriso@" if you want to override
-the default at first production time.  This option may also be used to
-explicitly set the preparer id as found in an ISO 9660 filesystem which
-shall be reproduced by a different version of xorriso.  The id can be
-inquired by the generic xorriso command -pvd_info.
 
 
 File: xorrisofs.info,  Node: Seealso,  Next: Bugreport,  Prev: Environ,  Up: Top
@@ -2617,32 +2644,33 @@ Node: Standards1573
 Node: Insert3878
 Node: Xorriso5724
 Node: Options6870
-Node: Loading7597
+Node: Loading7652
-Node: SetInsert9638
+Node: SetInsert9693
-Node: SetProduct15573
+Node: SetProduct15628
-Node: SetCompl21145
+Node: SetCompl21200
-Node: SetExtras23818
+Node: SetExtras23873
-Node: SetHide36210
+Node: SetHide36265
-Node: ImageId38209
+Node: ImageId38264
-Node: Bootable42491
+Node: Bootable42546
-Node: SystemArea48924
+Node: SystemArea48979
-Node: Charset70235
+Node: Charset70290
-Node: Jigdo71260
+Node: Jigdo71315
-Node: Miscellaneous76230
+Node: Miscellaneous76285
-Node: Examples78826
+Node: Reproducible78885
-Node: ExSimple79320
+Node: Examples81391
-Node: ExGraft79803
+Node: ExSimple81885
-Node: ExMkisofs81103
+Node: ExGraft82368
-Node: ExGrowisofs82911
+Node: ExMkisofs83668
-Node: ExIncBackup84101
+Node: ExGrowisofs85476
-Node: ExIncBckAcc87277
+Node: ExIncBackup86666
-Node: ExBootable88982
+Node: ExIncBckAcc89842
-Node: Files93164
+Node: ExBootable91547
-Node: Environ94259
+Node: Files95729
-Node: Seealso95834
+Node: Environ96824
-Node: Bugreport96535
+Node: Seealso97242
-Node: Legal97128
+Node: Bugreport97943
-Node: CommandIdx98025
+Node: Legal98536
-Node: ConceptIdx115531
+Node: CommandIdx99433
+Node: ConceptIdx116939
 
 End Tag Table

xorriso/xorrisofs.texi

@@ -50,7 +50,7 @@
 @c man .\" First parameter, NAME, should be all caps
 @c man .\" Second parameter, SECTION, should be 1-8, maybe w/ subsection
 @c man .\" other parameters are allowed: see man(7), man(1)
-@c man .TH XORRISOFS 1 "Version 1.5.7, Apr 24, 2025"
+@c man .TH XORRISOFS 1 "Version 1.5.7, Jun 10, 2025"
 @c man .\" Please adjust this date whenever revising the manpage.
 @c man .\"
 @c man .\" Some roff macros, for reference:
@@ -280,6 +280,7 @@ See EXAMPLES.
 * Charset::             Character sets
 * Jigdo::               Jigdo Template Extraction
 * Miscellaneous::       Miscellaneous options
+* Reproducible::        Reproducibility considerations
 @end menu
 @c man .PP
 @c man .TP
@@ -2290,7 +2291,7 @@ The rules for list_of_names are the same as with -checksum_algorithm_iso.
 @end table
 @c man .TP
 @c man .B Miscellaneous options:
-@node Miscellaneous, ExSimple, Jigdo, Options
+@node Miscellaneous, Reproducible, Jigdo, Options
 @section Miscellaneous options
 @table @asis
 @sp 1
@@ -2385,6 +2386,58 @@ Print to standard output a text that begins with
 @*
 and to standard error the version information of xorriso.
 @end table
+@c man .TP
+@c man .B Reproducibility considerations:
+@node Reproducible, Examples, Miscellaneous, Options
+@section Reproducibility considerations
+@c man .PP
+Stable versions of xorriso are prepared to produce in repeated runs from
+the same input files with the same file metadata and the same xorrisofs options
+the same ISO 9660 filesystem bytes. The only exception are bytes which depend
+on the current time of the xorriso run.
+@*
+These time dependent values can be set to fixed values by the options
+@minus{}@minus{}modification-date=, @minus{}@minus{}gpt_disk_guid, and
+@minus{}@minus{}set_all_file_dates. Instead of setting each of
+them, it is possible to influence them all by the environment variable
+SOURCE_DATE_EPOCH.
+@*
+SOURCE_DATE_EPOCH belongs to the specification of reproducible-builds.org.
+It is supposed to be either undefined or to contain a decimal number
+which tells the seconds since january 1st 1970. If it contains a number,
+then it is used as time value to set the default of
+@minus{}@minus{}modification-date=. @minus{}@minus{}gpt_disk_guid defaults
+to "modification-date". The default of @minus{}@minus{}set_all_file_dates
+is then "set_to_mtime". Further the "now" time for ISO nodes without disk
+source is set to the SOURCE_DATE_EPOCH value.
+@*
+Startup files and xorrisofs options can override the effect of
+SOURCE_DATE_EPOCH.
+@c man .PP
+@sp 1
+Different versions of xorriso may or may not produce the same result from
+the same input and options. Reproducibility may be prevented by bug fixes
+or feature enhancements between versions.
+@*
+xorriso puts its version information into the Preparer Id field of the
+ISO 9660 Primary Volume Descriptor by default. This may be desired in order
+to clearly define which xorriso version has to be used for reproduction.
+But it may also be undesired because a wider range of xorriso versions shall
+not be excluded from an attempt of reproduction.
+@*
+Use option -p with a text other than "@@xorriso@@" if you want to
+override the default at first production time. This option may also be used
+to explicitly set the preparer id as found in an ISO 9660 filesystem which
+shall be reproduced by a different version of xorriso. The preparer id can be
+inquired by xorriso command -pvd_info.
+@c man .PP
+@sp 1
+If reproducibility of xorrisofs results is desired, then the precautions - like
+setting SOURCE_DATE_EPOCH - should be done already with the original xorrisofs
+run. All input files, the used xorrisofs options in exact sequence, the version
+of xorriso, and the possibly set SOURCE_DATE_EPOCH value should then be kept
+or recorded for later re-use.
+@*
 @c man .br
 @node Examples, Files, Options, Top
 @chapter Examples
@@ -2959,31 +3012,8 @@ HOME is used to find xorriso and mkisofs startup files.
 @*
 MKISOFSRC may be used to point the program to a mkisofs startup file.
 @*
-@sp 1
-@c man .sp 1
 SOURCE_DATE_EPOCH belongs to the specs of reproducible-builds.org.
-It is supposed to be either undefined or to contain a decimal number
+See above paragraph "Reproducibility considerations".
-which tells the seconds since january 1st 1970. If it contains a number,
-then it is used as time value to set the default of
-@minus{}@minus{}modification-date=.
-@minus{}@minus{}gpt_disk_guid defaults to "modification-date".
-The default of @minus{}@minus{}set_all_file_dates is then "set_to_mtime".
-Further the "now" time for ISO nodes without disk source is then set to
-the SOURCE_DATE_EPOCH value.
-@*
-Startup files and program options can override the effect of SOURCE_DATE_EPOCH.
-@*
-Be aware that by default xorriso puts its version information into the
-Preparer Id field of the ISO 9660 Primary Volume Descriptor. This may be
-desired in order to clearly define which xorriso version has to be used for
-reproduction. But it may also be undesired because a wider range of xorriso
-versions shall not be excluded from an attempt of reproduction.
-@*
-Use option -p with a text other than "@@xorriso@@" if you want to
-override the default at first production time. This option may also be used
-to explicitly set the preparer id as found in an ISO 9660 filesystem which 
-shall be reproduced by a different version of xorriso. The id can be inquired
-by the generic xorriso command -pvd_info.
 @*
 @c man .SS 
 @c man .SH SEE ALSO