My client has seven iSeries systems, and the time is set by hand on each. This causes a swing of several minutes from the slowest to the fastest. A number of good tools exist that use time protocols to get the correct time from the Internet or perhaps even the more accurate GPS system. Most are written in 'C' and/or use sockets programming. These methods use several protocols NTP(SNTP) port 123, DAYTIME port 13, and TIME port 37.
My problem was that the client's network management group has these ports blocked at the firewall (and not FTP "go figure" ). So with some investigation, I found that by FTP-ing into the U.S. Navy time server I would get a welcome message containing the Coordinated Universal Time (UTC) time. Now this method has more overhead than standard SNTP and the accuracy will suffer. On my oldest and slowest system I find the time to be 5 to 8 seconds slow, but this is still far better than manually setting the clock.
The setup is quite simple. First create a dummy file for the compile requirement.
CRTPF FILE(QTEMP/FTPLOG) RCDLEN(132)
You will also need to create a source physical file named FTPTIME. Add to this file (using SEU) a TXT member named FTP. These two lines will log you into the FTP server. Edit the member adding these two lines:
anonymous your@email.com
quit
Now compile this CLP interactively with enough authority to change the sysval QTIME. Note: The line "DCL VAR(&UPDATE) TYPE(*LGL) VALUE('0')" must be changed to ('1') for the system value to be changed.
CL Program FTPTIME
/********************************************************************+
| +
| FTP to my FTP server and capture the login text which contains +
| the current UTC time. Then set the system time. +
| +
| Note: Job must run with authority that can CHGSYSVAL QTIME +
| This program requires you correctly set the SYSVAL +
| QUTCOFFSET for your time zone. +
| Tip: Using your browser go to www.time.gov for your time zone +
| offset value (US ONLY). International users may want to +
| use www.worldtimeserver.com and use the left side bar. +
| +
| Doug Hart 1/31/2002 +
| +
+*********************************************************************/
PGM
/*********************************************************************/
/* Local Variables */
/*********************************************************************/
/* Switch 0=no update, 1=update */
DCL VAR(&UPDATE) TYPE(*LGL) VALUE('0')
DCL VAR(&TGTSYS) TYPE(*CHAR) LEN(30) +
VALUE('dhart.no-ip.info') /* My FTP Server */
DCL VAR(&CMPSTR) TYPE(*CHAR) LEN(5) +
VALUE('220-Q') /* line compare string */
DCL VAR(&UTCSYSVAL) TYPE(*CHAR) LEN(5)
DCL VAR(&UTC) TYPE(*DEC) LEN(2 0)
DCL VAR(&UTCSIGN) TYPE(*CHAR) LEN(1)
DCL VAR(&HH) TYPE(*CHAR) LEN(2)
DCL VAR(&MM) TYPE(*CHAR) LEN(2)
DCL VAR(&SS) TYPE(*CHAR) LEN(2)
DCL VAR(&HHN) TYPE(*DEC) LEN(2 0)
DCL VAR(&TIME) TYPE(*CHAR) LEN(6)
DCL VAR(&QTIME) TYPE(*CHAR) LEN(6)
/********************************************************************/
/* Setup variables for QCLSCAN program */
/********************************************************************/
DCL VAR(&STRING) TYPE(*CHAR) LEN(132)
DCL VAR(&STRLEN) TYPE(*DEC) LEN(3 0) VALUE(132)
DCL VAR(&STRPOS) TYPE(*DEC) LEN(3 0) VALUE(25)
DCL VAR(&PATTERN) TYPE(*CHAR) LEN(1) +
VALUE(':')
DCL VAR(&PATLEN) TYPE(*DEC) LEN(3 0) VALUE(1)
DCL VAR(&TRANSLATE) TYPE(*CHAR) LEN(1) VALUE('0')
DCL VAR(&TRIM) TYPE(*CHAR) LEN(1) VALUE('0')
DCL VAR(&WILD) TYPE(*CHAR) LEN(1) VALUE(' ')
DCL VAR(&RESULT) TYPE(*DEC) LEN(3 0) VALUE(1)
/********************************************************************/
/* File in QTEMP that will be parsed for time string */
/* To compile program, file must be created and in libl */
/********************************************************************/
DCLF FILE(FTPLOG)
/********************************************************************/
/* Get UTC time offset hours and + or - sign from sysval */
/********************************************************************/
RTVSYSVAL SYSVAL(QUTCOFFSET) RTNVAR(&UTCSYSVAL)
CHGVAR VAR(&UTCSIGN) VALUE(%SST(&UTCSYSVAL 1 1))
CHGVAR VAR(&UTC) VALUE(%SST(&UTCSYSVAL 2 2))
/********************************************************************/
/* Build the FTP login file. */
/* This file has only two records holding the password and email */
/* and the FTP command QUIT needed for the Navy FTP server. */
/* ex: ANONYMOUS */
/* QUIT */
/* Note: This can be setup once manually using SEU */
/********************************************************************/
/* CRTSRCPF FILE(*LIBL/FTPTIME) RCDLEN(140) MBR(FTP) */
/********************************************************************/
/* Delete/Create the FTP transfer log file */
/********************************************************************/
DLTF FILE(QTEMP/FTPLOG)
MONMSG MSGID(CPF0000)
CRTPF FILE(QTEMP/FTPLOG) RCDLEN(132) MBR(FTPLOG)
/********************************************************************/
/* Execute FTP transfer */
/********************************************************************/
OVRDBF FILE(INPUT) TOFILE(*LIBL/FTPTIME) MBR(FTP)
OVRDBF FILE(OUTPUT) TOFILE(QTEMP/FTPLOG) MBR(FTPLOG)
STRTCPFTP RMTSYS(&TGTSYS)
DLTOVR FILE(*ALL)
/********************************************************************/
/* Parse FTPLOG file for time string */
/********************************************************************/
READ: RCVF
MONMSG MSGID(CPF0864) EXEC(GOTO CMDLBL(END))
/* End of file found and record not found = error */
IF COND(%SST(&FTPLOG 1 5) = &CMPSTR) THEN(DO) +
/********************************************************************/
/* Found time string line in log starting with "220-Q" */
/* Now parse the line for ':' to get time position */
/* Then convert the string to HH MM SS values */
/********************************************************************/
CHGVAR VAR(&STRING) VALUE(&FTPLOG)
CALL PGM(QCLSCAN) PARM(&STRING &STRLEN &STRPOS +
&PATTERN &PATLEN &TRANSLATE &TRIM &WILD +
&RESULT)
IF COND(&RESULT = 0) THEN(GOTO CMDLBL(END))
/* Time ':' not found in string = error */
CHGVAR VAR(&RESULT) VALUE(&RESULT - 2)
CHGVAR VAR(&HH) VALUE(%SST(&FTPLOG &RESULT 2))
CHGVAR VAR(&RESULT) VALUE(&RESULT + 3)
CHGVAR VAR(&MM) VALUE(%SST(&FTPLOG &RESULT 2))
CHGVAR VAR(&RESULT) VALUE(&RESULT + 3)
CHGVAR VAR(&SS) VALUE(%SST(&FTPLOG &RESULT 2))
/********************************************************************/
/* Adjust to your time zone */
/********************************************************************/
CHGVAR VAR(&HHN) VALUE(&HH)
IF COND(&UTCSIGN = '-') THEN(DO)
CHGVAR VAR(&HHN) VALUE(&HHN - &UTC)
IF COND(&HHN < 0) THEN(CHGVAR VAR(&HHN) +
VALUE(24 + &HHN))
ENDDO
ELSE CMD(DO) /* &UTCSIGN = '+' */
CHGVAR VAR(&HHN) VALUE(&HHN + &UTC)
IF COND(&HHN > 23) THEN(CHGVAR VAR(&HHN) +
VALUE(&HHN - 24))
ENDDO
CHGVAR VAR(&HH) VALUE(&HHN)
/********************************************************************/
/* Set the system value QTIME */
/********************************************************************/
CHGVAR VAR(&TIME) VALUE(&HH || &MM || &SS)
RTVSYSVAL SYSVAL(QTIME) RTNVAR(&QTIME)
IF COND(&UPDATE) +
THEN(CHGSYSVAL SYSVAL(QTIME) VALUE(&TIME))
SNDPGMMSG MSGID(CPF9898) MSGF(QCPFMSG) MSGDTA('System +
time changed from' |> %SST(&QTIME 1 2) || +
':' || %SST(&QTIME 3 2) || ':' || +
%SST(&QTIME 5 2) |> 'to' |> &HH || ':' || +
&MM || ':' || &SS |> 'by FTPTIME +
program') MSGTYPE(*INFO)
RETURN /* Good completion */
ENDDO
GOTO CMDLBL(READ) /* get next record loop */
/********************************************************************/
/* On error send mesage */
/********************************************************************/
END: SNDPGMMSG MSGID(CPF9898) MSGF(QCPFMSG) MSGDTA('FTP +
time process ended in ERROR. Check +
joblog for details, or review the QTEMP +
files FTPCMD and FTPLOG.') MSGTYPE(*ESCAPE)
ENDPGM
If you wish to automate the Daylight saving time adjustment of your sysval QUTCOFFSET use this 2nd small CLP. Note: the values are for the East coast U.S. only, change them as needed for your location (see red). This program can be setup in any basic job scheduler to run every Sunday at 2:00.
Daylight saving time starts the 1st Sunday in April at 2 a.m. It ends the last Sunday in October at 2 a.m. (These are U.S. rules.)
CL Program ADJUTC
/* ----------------------------------------------------------------- +
| Program: ADJUTC Adjust UTC Sysval +
| Date : 2/05/2002 +
| Author : D. Hart +
| +
| Function: Adjust for Daylight Saving Time the system value +
| QUTCOFFSET. This is only for the Eastern US time zone +
| Run this job every Sunday at 02:00 in system job +
| scheduler. +
| Tip: see http://webexhibits.org/daylightsaving/b.html for more. +
| +
| Coordinated Universal Time -4 hours; Daylight Saving Time +
| Coordinated Universal Time -5 hours; Eastern Standard Time +
| +
L ----------------------------------------------------------------- */
PGM
DCL VAR(&DAYOFWEEK) TYPE(*CHAR) LEN(4)
DCL VAR(&MONTH) TYPE(*CHAR) LEN(2)
DCL VAR(&DAY) TYPE(*CHAR) LEN(2)
/* Ensure that this is a Sunday */
RTVSYSVAL SYSVAL(QDAYOFWEEK) RTNVAR(&DAYOFWEEK)
IF COND(&DAYOFWEEK *EQ '*SUN') THEN(DO)
RTVSYSVAL SYSVAL(QMONTH) RTNVAR(&MONTH)
RTVSYSVAL SYSVAL(QDAY) RTNVAR(&DAY)
/* 1ST Sunday in April start Daylight Saving Time */
IF COND(&MONTH = '04' *AND &DAY *LE '07') THEN( +
CHGSYSVAL SYSVAL(QUTCOFFSET) VALUE('-0400'))
/* Last Sunday in October end Daylight Saving Time */
IF COND(&MONTH = '10' *AND &DAY *GE '25') THEN( +
CHGSYSVAL SYSVAL(QUTCOFFSET) VALUE('-0500'))
ENDDO
ENDPGM
