=;The OpenVMS Frequently Asked Questions (FAQ)D

The OpenVMS Frequently Asked Questions (FAQ)



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4.4.1 Creating, Updating and Managing Timezone Definitions?



GOne issue with the UTC implementation on OpenVMS is the behaviour of C Dfunctions and other programs that use SYS$TIMEZONE_RULE; the OpenVMSFmechanism assumes all control over the timezone and the daylight time Eswitchover. This allows calculation of the time by the C library and various applications.

DThis can be incompatible with a system or application that requires Dmanual modifications to the DST or TDF settings, or that requires a Glocal or customized timezone definition. For such a site to ensure the Ftimekeeping is correct, the site must provide procedure that sets the @local time and the TDF when the SYS$TIMEZONE_RULE says to do it.

GIf a site requires a non-standard time switch-over, as in coordinating Hwith a shift change or due to changes in the local or regional timezone $rules, the site will need to use the.zic compiler to create a custom timezone rule.

EAdditionally, applications may need to have special actions taken or @actions queued just before the time change takes effect. If the Eapplication source code is available, one of the best ways to handle Fthis is via the TDF and time-change notification events available via the OpenVMS sys$set_system_event system service.

DFor information on zic and related tools used to manage the OpenVMS BTimezone database, please see the HP C Run-time Library Utilities @Reference Manual---though the title would imply otherwise, this Dparticular manual is part of the OpenVMS documentation set, and not Gpart of the HP C (formerly Compaq C, formerly DEC C) documentation set.

RFor related information, see Section 4.4.1.1.Z

4.4.1.1 Customizing or Updating your TDF (Timezone) Setting?



GIndividual, local, and regional differences on the use (or the lack of Guse) of Daylight Saving Time (DST) are quite common, as are occasional Gregulatory changes to the particular applicable regional DST settings. G(eg: The United States Government is expecting to change its DST rules gstarting 1-Mar-2007; please see Section 4.4.1.2 for details.)

AIf you need to add, modify or remove DST rules for your area, or Hotherwise alter the rules for your local area, you will probably end up Bcreating a variation to an existing timezone rule, or potentially Gsimply downloading a new set of DST rules. This requirement can arise, >for instance, if your local region changes its timezone rules.

CThe necessary zone line to add for support of the hypothetical new >WhereEverLand timezone will probably look something like this:

 

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@# Zone  NAME            GMTOFF  RULES/SAVE      FORMAT  [UNTIL] :Zone    WhereEver       2:00    -               WhereEver 




@The OpenVMS source files for the timezone rules are stored here:

 

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)SYS$COMMON:[SYS$ZONEINFO.SYSTEM.SOURCES] 




AYou'll then want to use the zic compiler to compile your own new Etimezone definition, or to compile a new set of timezone definitions :that have been freshly downloaded from a published source.

EThe zic compiler is documented in the OpenVMS Documentation Set, and Especifically in the HP C Run-Time Library Reference Manual. (Despite Ethe name of this manual, it is part of the OpenVMS documentation set and not of the C manuals.)

@Once you have created and compiled a new timezone rule (or have Edownloaded and have compiled a whole new set of timezone rules), use "the SYS$MANAGER:UTC$TIME_SETUP.COMDto select the new timezone if necessary---with V7.3 and later, this Dtool will automically notice the new timezone and will offer it, on Aearlier releases, you may/will have to hack the code of the tool Gsomewhat to allow it to present the new timezone rule. (If an existing Ctimezone rule is simply changing, you don't need this re-selection step.)



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Note

kAs mentioned in Section 4.4.2, please don't modify or redefine the TZ4logical name (found on older configurations), or theSYS$TIMEZONE_NAME logical name,Hor any other time- or timezone-related logical names directly yourself. BRather, please use the zic compiler and/or the UTC$TIME_SETUP.COM procedure.


HFor various published timezone rules or updated to same, see the tar.gz 4files (these are gzipped tar archives) available at:



EThese are gzipped tar archives, and are the pubished source used for Ethe OpenVMS timezone rules on OpenVMS V7.3 and later, and within the Bpredecessor C run-time environment timezone support used on older EOpenVMS releases. You'll need to first gunzip and then use vmstar to /unpack and access the contents of the archives.

GThe published timezone rules include the effective date ranges for the Eindividual rules, so you can reload your rules prior to a particular Aset of new rules becoming effective. The effective dates for the Bparticular timezone rules are additionally necessary to allow the Happropriate translation of older dates and times within the appropriate 9historical context of the particular date and time value.

QFor related information, see Section 4.4.1.X

4.4.1.2 US Daylight Time Changes Starting 1-Mar-2007?



FThe United States Federal Government is presently expecting to change 'its DST rules starting with 1-Mar-2007.

FAs amended, US daylight time will be increased to run from the second FSunday in March through the first Sunday of October, inclusive. Other Hcountries, US local political geographies and businesses may or may not 4follow suite and implement these changes, obviously.

HFor further regulatory details, see the US Uniform Time Act of 1966 (15 <U.S.C 260a(a)), as amended by the Energy Policy Act of 2005.

HFor details on how to create, customize or to download new rules and to bupdate your local timezone rules, please see Section 4.4.1.1.N

4.4.2 Timezones and Time-related Logical Names?



EVarious logical names are used to manage time and timezones, and you ?should avoid direct modification of these logical names as the Himplementations are subtle and quick to change. As discussed in section kSection 4.4.3, you will want to use the following command procedure to #maintain the time and the timezone:



EIf you want to venture into uncharted territories and modify the TDF Fused within older releases of TCP/IP Services---within releases prior BV5.0---you can attempt to use the following undocumented commands:

 

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1SET TIME/DIFF=[positive or negative TDF integer] GENERATE TIME 




/to reset the value of the logical name UCX$TDF.

#Prior to OpenVMS V7.3, the command:

 

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*$ SETTZ :== $SYS$SYSTEM:DTSS$SET_TIMEZONE $ SETTZ MODIFY 




Hcan be used to modify the settings of the SYS$TIMEZONE_DAYLIGHT_SAVING, FSYS$TIMEZONE_DIFFERENTIAL, and SYS$TIMEZONE_NAME system logical names based on the SYS$TIMEZONE_RULE.

DThe following are other TDF-related logical names used/available on GOpenVMS systems, with typical daylight time and standard time settings &for the US Eastern Time (ET) timezone.

 

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$daylight_time: ,$ DEFINE/SYSTEM/EXECUTIVE MAIL$TIMEZONE EDT 5$ DEFINE/SYSTEM/EXECUTIVE NOTES$TIMEZONE "-0400 EDT" H$ DEFINE/SYSTEM/EXECUTIVE LISP$DAYLIGHT_SAVING_TIME_P true  ! Not 'EDT' 9$ DEFINE/SYSTEM/EXECUTIVE LISP$TIME_ZONE 05   ! Constant $ $standard_time: ,$ DEFINE/SYSTEM/EXECUTIVE MAIL$TIMEZONE EST 5$ DEFINE/SYSTEM/EXECUTIVE NOTES$TIMEZONE "-0500 EST" H$ DEFINE/SYSTEM/EXECUTIVE LISP$DAYLIGHT_SAVING_TIME_P false ! Not 'EST' 9$ DEFINE/SYSTEM/EXECUTIVE LISP$TIME_ZONE 05   ! Constant $ 6$ DEFINE/SYSTEM/EXECUTIVE UCX$NFS_TIME_DIFFERENTIAL - C    'f$integer(f$element(0," ",f$logical("notes$timezone"))/-100)' 




AFor information on modifying these timezone logical names and on Umanaging the timezone rules, see Section 4.4.1.O

4.4.3 How to troubleshoot TDF problems on OpenVMS?



EThis is an OpenVMS Alpha system prior to V7.0 and the startup is not invoking the procedure:

 

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SYS$MANAGER:UTC$TIME_SETUP.COM 




GThis is an OpenVMS system prior to V6.0, where there is no OpenVMS TDF nor UTC available.

BThe version of the application does not use the OpenVMS TDF. This Fincludes TCP/IP Services prior to V5.0, applications using HP C built =on or targeting OpenVMS prior to V7.0, and systems using the ADECnet-Plus DTSS mechanisms prior to the release associated with @OpenVMS V7.3. (DCE DTS TDF management details to be determined.)

@If you should find either of the following two timezone-related 0database files located in SYS$SPECIFIC:[SYSEXE]:



FThese two files are in an erroneous location and must be recreated in the correct directory:

 

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SYS$COMMON:[SYSEXE] 




If the DCL command:

 

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)$ DIRECTORY SYS$SYSTEM:SYS$TIMEZONE*.DAT 




Eshows these files in SYS$SPECIFIC:[SYSEXE], then delete them and use 0SYS$MANAGER:UTC$TIME_SETUP.COM to recreate them.

/On OpenVMS versions prior to V7.3, if the file:

 

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#$ SYS$STARTUP:DTSS$UTC_STARTUP.COM 




7is present on your system, then you may need to invoke:

 

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-$ @SYS$UPDATE:DTSS$INSTALL_TIMEZONE_RULE.COM 




>to recreate the timezone files correctly. Invoke this command @immediately after [re]executing SYS$MANAGER:UTC$TIME_SETUP.COM.)

DIf SYS$UPDATE:DTSS$INSTALL_TIMEZONE_RULE.COM is not present on your <system, then you may need to execute the following commands:

 

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*$ DELETE SYS$STARTUP:DTSS$UTC_STARTUP.COM *$ DEASSIGN/SYSTEM/EXEC SYS$TIMEZONE_RULE. 




CIf your system time is being reported as being off by one hour (or fwhatever the local DST change), please see sections Section 4.7, jSection 4.4 and Section 10.22.1.t

4.5 Why does the SET TIME command fail? Help managing DTSS?



EIf you try to set the system time with the SET TIME command, and see one of the following messages:

 

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$%SET-E-NOTSET, error modifying time 1-SYSTEM-F-IVSSRQ, invalid system service request  $%SET-E-NOTSET, error modifying time ,-SYSTEM-E-TIMENOTSET, time service enabled; 2  enter a time service command to update the time 




DThis occurs if the time on the local system is controlled by a time Dservice software, for example the distributed time service software B(DTSS) provided as part of the DECnet-Plus installation. The DTSS Bsoftware communicates with one or more time servers to obtain the >current time. It entirely controls the local system time (for ;DECnet-Plus, there is a process named DTSS$CLERK for this);Atherefore, the usage of the SET TIME command (and the underlying $$SETTIM system service) is disabled.

GThe first message is displayed on systems running DECnet-Plus V6.1 and Eearlier. On systems with newer DECnet-Plus software, the second (and #more informative) message is given.

EYou shouldn't have to change the time manually - you should be doing Cthis through the time server - but if you insist... you'll have to shutdown DTSS:

 

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$ RUN SYS$SYSTEM:NCL 
DISABLE DTSS DELETE DTSS 




FThis will shutdown DTSS$CLERK. You may then change the system time as )usual. To restart the DTSS software, type

 

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$ @SYS$STARTUP:DTSS$STARTUP 




DYou will need a number of privileges to ussue this command, and you Amust also be granted the NET$MANAGE identifer to shutdown and to restart DTSS.

HIf you wish to "permanently" disable DTSS on a system running DDECnet-Plus, the above NCL sequence must be performed each time the Gsystem is bootstrapped. (On DECnet-Plus V7.3 and later, you can define !the logical name NET$DISABLE_DTSSG to disable the DTSS startup. This logical name must be defined in the " command procedure SYLOGICALS.COM,H as this logical name must be present and defined sufficiently early in ; the OpenVMS system bootstrap sequence for it to function.)

DIf DTSS is running and no time servers are configured, you can (and 6will) see the following messages at regular intervals:

 

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9%%%%%%%%%%%  OPCOM   2-SEP-1999 19:41:20.29  %%%%%%%%%%% #Message from user SYSTEM on UNHEDI ?Event: Too Few Servers Detected from: Node LOCAL:.mynode DTSS, .        at: 1999-09-02-19:41:20.296-04:00Iinf         Number Detected=0,         Number Required=1 8        eventUid   5FA70F4F-616E-11D3-A80E-08002BBEDB0F 8        entityUid  DE9E97DE-6135-11D3-8004-AA000400BD1B 8        streamUid  D6513A46-6135-11D3-8003-AA000400BD1B 




HYou can either configure the appropriate number of time servers, or you Hcan disable DTSS, or you can ignore it and (if OPCOM is set to write to %the log via via the logical names in ESYLOGICALS.COM/SYLOGICALS.TEMPLATE) clean out OPERATOR.LOG regularly.

:You can also simply disable the display of these messages:

 

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$ run sys$system:ncl 6block event dispatcher outbound stream local_stream -     global filter - -    ((Node, DTSS), Too Few Servers Detected) 




EIf you wish to disable the automatic TDF adjustment for the daylight Ftime switch-over (on OpenVMS versions prior to V7.3), you can use the command:

 

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$ run sys$system:ncl &set dtss automatic TDF change = false 




For alternatively, you can set the local timezone to one that does not 0include the automatic daylight time change-over.

=OpenVMS V7.3 and later simplify time and timezone management.w

4.6 Setting time on AlphaServer ES47, ES80, GS1280 console?



BTo set the base system time on an member of the AlphaServer ES47, FAlphaServer ES80 or AlphaServer GS1280 series system family, you must Eaccess the Platform Management Utility (PMU). The PMU is implemented Dwithin this family of related AlphaServer systems, and is part of a Clayer providing services beyond those of the traditional Alpha SRM Fconsole layer, and within a layer architecturally implemented beneath ?the SRM console. In particular, the PMU and related management 7components are used to provide services across multipleG vPars or nPars partitions. In particular, the SRM obtains and manages H the local system time on these systems as a delta time offset from the B underlying base system time. Neither the SRM console nor OpenVMS H directly accesses nor alters the underlying base system time nor other - information maintained within the PMU layer.

GThe PMU uses the System Management components, centrally including the EBackplane Manager (MBM) module found in each drawer, user interface, HPCI and CPU management components, and the interconnections among these Cprovided by the private system management LAN. When the system has @power applied and the main breakers are on, the MBMs are active.

GThe PMU offers a command line interface for a serial communications or Htelnet connection and allows command and control of the MBM, and of the =server. The PMU and the MBM system management components are $responsible for the following tasks:



CYou can use the MBM commands SHOW TIME and SET TIME to view and to Fmanipulate the base system time. The delta time value for the primary DMBM will be indicated, and it is this value in conjunction with the Ebase time that is used to generate the time available to OpenVMS via Hthe SRM console. If you issue a SET TIME=time command from OpenVMS, the Hdelta time will change, but not the MBM base system time. If you change Gthe MBM base system time, the calculated time available to OpenVMS via Gthe SRM console(s) will change. (Resetting the base time thus involves >changing the base system time, and then issuing SET TIME=time Hcommand(s) to each of the OpenVMS vPars or nPars environments to adjust Fthe respective delta time values.) Rebooting, resetting or issuing an (MBM SET TIME will reset the system time.

CTypically, you will want to establish the MBM time value once, and Hprobably setting it to UTC or such, and you will then want to boot each /partition conversationally, setting the SETTIMEDsystem parameter to force the entry of the time within each booting Hsystem environment. Once the MBM time value has been set once, you will Htypically not want to alter it again. You will typically want to manage 6and modify only the time values within each partition.

EThe time and data values stored in the primary MBM and replicated in Hthe zero or more secondary MBMs that might be present within the system are coordinated.

?To enter the PMU from the SRM console, and to exit back to SRM:

 

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)MBM - (PMU, Platform Management Utility)  )  From SRM P00> enter {Esc} {Esc} MBM 6  CTRL/[ CTRL/[ MBM           (MBM must be uppercase) 2  MBM> connect                (to exit to SRM) 




CThe [CTRL/][ is the escape character. Use the cited key Bsequences to enter the PMU. You can also access the PMU through a Bmodem, or from a terminal or terminal emulator or terminal server Econnected to the server management LAN. Having the server management GLAN bridged to an untrusted LAN can be unwise, however, and with risks Eanalogous to those of configuring a traditional VAX or Alpha console =serial line to an open terminal server or to a dial-in modem.

DSee the AlphaServer GS1280 documentation for additional information.w

4.7 UTC vs GMT vs vs UT1/UT1/UT2 TDF? What are these acronyms?



FThe results of an international compromise---though some would say an Cinternational attempt to increase confusion---UTC is refered to as F"Coordinated Universal Time" (though not as CUT) in English Hand as "Temps Universel Coordinné" (though not as TUC) Din French. (No particular information exists to explain why UTC was Achosen over the equally nonsensical TCU, according to Ulysses T. =Clockmeister, one of the diplomats that helped establish the international compromise.)

DUniversal Time UT0 is solar time, UT1 is solar time corrected for a Cwobble in the Earth's orbit, and UT2 is UT1 corrected for seasonal Arotational variations in rotation due to the Earth's solar orbit.

HGMT---Greenwich Mean Time---is UT1. GMT is the time at the classic site @of the since-disbanded Royal Greenwich Observatory; at the most 6widely-known tourist attraction of Greenwich, England.

FUTC is based on an average across multiple atomic clocks, and is kept Awithin 0.9 seconds of GMT, through the insertion (or removal) of Aseconds. In other words, UTC matches GMT plus or minus up to 0.9 seconds, but UTC is not GMT.

FTDF is the Timezone Differential Factor, the interval of time between Hthe local time and UTC. Areas that celebrate daylight saving time (DST) Awill see periodic changes to the TDF value, when the switch-over Gbetween daylight time and standard time occurs. The switch-over itself His entirely left to local governmental folks, and can and has varied by Gpolitical entity and politics, and the switch-over has varied over the years even at the same location.

FIf your local OpenVMS system time is off by one hour (or whatever the Elocal DST change) for some or all applications, you probably need to @reset your local TDF. (For related details, please see sections kSection 4.4 and Section 10.22.1.)

BFurther discussions of history and politics, the Royal Observers' Eoutbuildings, and the compromise that left the English with the Time CStandard (the Prime Meridian) and the French with the standards forHDistance and Weight (the Metric System) are left to other sources. Some 2of these other sources include the following URLs:






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