25
Thu, Apr
1 New Articles

i5/OS, OS/400, and Daylight Saving Time (DST)

Typography
  • Smaller Small Medium Big Bigger
  • Default Helvetica Segoe Georgia Times

Remember Y2K? Well, next Sunday seems to have a lot of people unnecessarily worried about the change in when Daylight Saving Time (DST) goes into effect.

I suppose if you are still running an iSeries with OS/400 V5R2 or earlier, you don't have DST support anyway, so you shouldn't be worried. It wasn't until V5R3 that IBM introduced DST to the iSeries world. The time zone system value (QTIMZON) specifies the name of the time zone description that is used to calculate local system time.

Just for the record, DST begins at 2:00 a.m. on March 11, 2007, so move your clocks ahead one hour. DST ends at 2:00 a.m. on November 11, 2007. You'll move your clocks back an hour then.

My System i5 system is running i5/OS V5R4. The QTIMZON system value is set to QN0600CST2. This is the Time Zone Descriptor that IBM created to indicate that we're at Zulu – 6 (this means I'm six hours earlier than Greenwich Mean Time).

A new command, Work with Time Zone Descriptors (WRKTIMZON), allows you to work with all the installed time zone descriptors. Although you probably don't need to use it, this command displays a list of all the various descriptors and allows you to easily select which one you want to use for your QTIMZON system value (type an 8 next to the time zone descriptor, and the QTIMZON system value is changed to this value). In addition, the F11 key can be used to toggle between displaying the DST descriptors only, standard time descriptors, or all descriptors (see Figure 1).

http://www.mcpressonline.com/articles/images/2002/i5--03070700.jpg

Figure 1: With the WRKTIMZON command, you can use the F11 key to toggle between displaying the DST descriptors only, standard time descriptors, or all descriptors. (Click images to enlarge.)

It may appear as though there are duplicate time zone descriptors, but many are simply the result of installing IBM PTFs for DST. For example, the QN0600CST2 descriptor represents the new DST standard, whereas QN0600CST represents the original DST standard.

If you display the QTIMZON value, it will look similar to Figure 2 (shown on my machine):

http://www.mcpressonline.com/articles/images/2002/i5--03070701.jpg

Figure 2: Display the QTIMZON system value.

If you're on V5R2 and DST is important, you have to adjust your applications so that they access this kind of information via Internet Web sites, SOA, or another method. Or you may have to move to V5R3 or V5R4.

If you are running V5R3 or later, IBM has PTFs that will correct the change in DST duration:

  • V5R3—SI26039 and SI25991
  • V5R4—SI26040 and SI25990

If you're current on PTF packages, these PTFs are probably already applied to your system. If not, you need to make sure you get them installed in the next few days. Go to the IBM OS/400 and i5/OS DST PTF Web site to find out more about this issue.

To find out more about DST, visit the National Institute of Standards Web page on DST.

What About Java?

Normally, I would say, "Who cares?" But Java is finally becoming relatively useful. I now use it to send email responses to people who register on the discussion forum at RPGIV.com/forum, and it works well.

IBM's Java has all kinds of PTFs listed for DST support. Since the Java Developer Kit (JDK) is at various levels, there are various PTFs based on the JDK release and the i5/OS release you're running. Here's a short matrix; identify your JDK and i5/OS release and pull down the PTF(s) you'll need.

PTFs DST Support
JDK Version
V5R2
V5R3
V5R4
1.2.2
SI26480
N/A
N/A
1.3.1
SI25967
SI25968
SI25969
1.4
SI25966
SI26838
SI26839

If you're using Unicode (most people are not, but some are), you need one of the following PTFs for your ICU DST (5722SS1 Option 29):

  • V5R4M0—SI25400
  • V5R3M0—SI25399

At the end of the day, you may forget to turn your clocks forward an hour ("spring forward, fall back"), but your iSeries should be keeping pace with the rest of the world, provided you've installed these DST PTFs.

Bob Cozzi is author of the best-selling The Modern RPG IV Language, Fourth Edition as well as RPG TNT: 101 Dynamite Tips 'n Techniques with RPG IV and is host of the i5 Podcast Network, which provides free video and audio podcasts to the i5 community. You can also see him in person at RPG World in May 2007.

BOB COZZI

Bob Cozzi is a programmer/consultant, writer/author, and software developer. His popular RPG xTools add-on subprocedure library for RPG IV is fast becoming a standard with RPG developers. His book The Modern RPG Language has been the most widely used RPG programming book for more than a decade. He, along with others, speaks at and produces the highly popular RPG World conference for RPG programmers.


MC Press books written by Robert Cozzi available now on the MC Press Bookstore.

RPG TnT RPG TnT
Get this jam-packed resource of quick, easy-to-implement RPG tips!
List Price $65.00

Now On Sale

The Modern RPG IV Language The Modern RPG IV Language
Cozzi on everything RPG! What more could you want?
List Price $99.95

Now On Sale

BLOG COMMENTS POWERED BY DISQUS

LATEST COMMENTS

Support MC Press Online

$0.00 Raised:
$

Book Reviews

Resource Center

  • SB Profound WC 5536 Have you been wondering about Node.js? Our free Node.js Webinar Series takes you from total beginner to creating a fully-functional IBM i Node.js business application. You can find Part 1 here. In Part 2 of our free Node.js Webinar Series, Brian May teaches you the different tooling options available for writing code, debugging, and using Git for version control. Brian will briefly discuss the different tools available, and demonstrate his preferred setup for Node development on IBM i or any platform. Attend this webinar to learn:

  • SB Profound WP 5539More than ever, there is a demand for IT to deliver innovation. Your IBM i has been an essential part of your business operations for years. However, your organization may struggle to maintain the current system and implement new projects. The thousands of customers we've worked with and surveyed state that expectations regarding the digital footprint and vision of the company are not aligned with the current IT environment.

  • SB HelpSystems ROBOT Generic IBM announced the E1080 servers using the latest Power10 processor in September 2021. The most powerful processor from IBM to date, Power10 is designed to handle the demands of doing business in today’s high-tech atmosphere, including running cloud applications, supporting big data, and managing AI workloads. But what does Power10 mean for your data center? In this recorded webinar, IBMers Dan Sundt and Dylan Boday join IBM Power Champion Tom Huntington for a discussion on why Power10 technology is the right strategic investment if you run IBM i, AIX, or Linux. In this action-packed hour, Tom will share trends from the IBM i and AIX user communities while Dan and Dylan dive into the tech specs for key hardware, including:

  • Magic MarkTRY the one package that solves all your document design and printing challenges on all your platforms. Produce bar code labels, electronic forms, ad hoc reports, and RFID tags – without programming! MarkMagic is the only document design and print solution that combines report writing, WYSIWYG label and forms design, and conditional printing in one integrated product. Make sure your data survives when catastrophe hits. Request your trial now!  Request Now.

  • SB HelpSystems ROBOT GenericForms of ransomware has been around for over 30 years, and with more and more organizations suffering attacks each year, it continues to endure. What has made ransomware such a durable threat and what is the best way to combat it? In order to prevent ransomware, organizations must first understand how it works.

  • SB HelpSystems ROBOT GenericIT security is a top priority for businesses around the world, but most IBM i pros don’t know where to begin—and most cybersecurity experts don’t know IBM i. In this session, Robin Tatam explores the business impact of lax IBM i security, the top vulnerabilities putting IBM i at risk, and the steps you can take to protect your organization. If you’re looking to avoid unexpected downtime or corrupted data, you don’t want to miss this session.

  • SB HelpSystems ROBOT GenericCan you trust all of your users all of the time? A typical end user receives 16 malicious emails each month, but only 17 percent of these phishing campaigns are reported to IT. Once an attack is underway, most organizations won’t discover the breach until six months later. A staggering amount of damage can occur in that time. Despite these risks, 93 percent of organizations are leaving their IBM i systems vulnerable to cybercrime. In this on-demand webinar, IBM i security experts Robin Tatam and Sandi Moore will reveal:

  • FORTRA Disaster protection is vital to every business. Yet, it often consists of patched together procedures that are prone to error. From automatic backups to data encryption to media management, Robot automates the routine (yet often complex) tasks of iSeries backup and recovery, saving you time and money and making the process safer and more reliable. Automate your backups with the Robot Backup and Recovery Solution. Key features include:

  • FORTRAManaging messages on your IBM i can be more than a full-time job if you have to do it manually. Messages need a response and resources must be monitored—often over multiple systems and across platforms. How can you be sure you won’t miss important system events? Automate your message center with the Robot Message Management Solution. Key features include:

  • FORTRAThe thought of printing, distributing, and storing iSeries reports manually may reduce you to tears. Paper and labor costs associated with report generation can spiral out of control. Mountains of paper threaten to swamp your files. Robot automates report bursting, distribution, bundling, and archiving, and offers secure, selective online report viewing. Manage your reports with the Robot Report Management Solution. Key features include:

  • FORTRAFor over 30 years, Robot has been a leader in systems management for IBM i. With batch job creation and scheduling at its core, the Robot Job Scheduling Solution reduces the opportunity for human error and helps you maintain service levels, automating even the biggest, most complex runbooks. Manage your job schedule with the Robot Job Scheduling Solution. Key features include:

  • LANSA Business users want new applications now. Market and regulatory pressures require faster application updates and delivery into production. Your IBM i developers may be approaching retirement, and you see no sure way to fill their positions with experienced developers. In addition, you may be caught between maintaining your existing applications and the uncertainty of moving to something new.

  • LANSAWhen it comes to creating your business applications, there are hundreds of coding platforms and programming languages to choose from. These options range from very complex traditional programming languages to Low-Code platforms where sometimes no traditional coding experience is needed. Download our whitepaper, The Power of Writing Code in a Low-Code Solution, and:

  • LANSASupply Chain is becoming increasingly complex and unpredictable. From raw materials for manufacturing to food supply chains, the journey from source to production to delivery to consumers is marred with inefficiencies, manual processes, shortages, recalls, counterfeits, and scandals. In this webinar, we discuss how:

  • The MC Resource Centers bring you the widest selection of white papers, trial software, and on-demand webcasts for you to choose from. >> Review the list of White Papers, Trial Software or On-Demand Webcast at the MC Press Resource Center. >> Add the items to yru Cart and complet he checkout process and submit

  • Profound Logic Have you been wondering about Node.js? Our free Node.js Webinar Series takes you from total beginner to creating a fully-functional IBM i Node.js business application.

  • SB Profound WC 5536Join us for this hour-long webcast that will explore:

  • Fortra IT managers hoping to find new IBM i talent are discovering that the pool of experienced RPG programmers and operators or administrators with intimate knowledge of the operating system and the applications that run on it is small. This begs the question: How will you manage the platform that supports such a big part of your business? This guide offers strategies and software suggestions to help you plan IT staffing and resources and smooth the transition after your AS/400 talent retires. Read on to learn: