Dear ExpressionFlow readers and fellow LabVIEW developers. I’m very excited to tell you, that recently I’ve founded a new Helsinki based company, Agile 4, providing LabVIEW software development related consultation services. Today, it’s time to come out of the shadows and public with the company.

Agile 4 Ltd. is a software design, development, and software strategy consulting start-up specialized in building state-of-the-art LabVIEW based technology solutions. We are comitted to providing our customers with the best possible software solutions and world class software expertise.

We at Agile 4 are enthusiastic about software development with LabVIEW. We want to help our customers succeed in their business environment by helping them to make the best possible software solutions for their market. We understand that software development is an investment and we think our customers should get the best value for their software related investments.

ExpressionFlow will continue to as a LabVIEW and visual programming blog. I’ll do my best to keep posting articles on subjects close to me and Agile 4.

For more information on the company, please visit Agile 4 website.

Today I transferred ExpressionFlow from my old shared hosting provider to Mosso hosting cloud. If you are experiencing any problems, please report them so I can get the problems fixed.

Mosso is a kind of hybrid solution. You get the easiness of shared hosting together with the power of a cloud. During the last six months I’ve been using Mosso to host several different web sites, and I must say I’ve been impressed by the simply superb customer service they have. When ever I’ve had any troubles at all, my problems are solved immediately by the very helpful and skilled customer service. I can’t say the same of my old hosting provider. For fixed price a month you can host an unlimited number of web sites on both Windows and Linux hosts limited only by the total consumed system resources a month. Actually, the only thing I’ve been missing is a hosting plan with less capacity than the only current hosting plan they’re providing. If you are interested in test driving Mosso, use the referral code REF-EXPRESSIONFLOW at sign-up and you’ll get $50 credit.

A leap second will be added at the end of the year 2008. That is after 23:59:59, a positive leap second at 23:59:60 would be counted, before the clock indicates 00:00:00 of the first day of 2009. The addition of a leap second may mesh up with the time synchronization of your software and your application may end up functioning in an unpredictable way. more…

How many times you have seen an error message window to pop-up in an application giving you a meaningless error message and all you can do is to press “Ok” or “Cancel” without any idea where the error message was related to. At best the error message gives you some hint what was wrong and you may get back on track with the application. However once you close the pop-up, you no longer have the details of the error message to help you with fixing the problem. Do the applications you yourself have developed behave this way?

Well, things don’t have to be this way? On the contrary, you as a developer should design applications so that you never let your users to find  themselves in situations like this. It’s not only a benefit of the user, but also a benefit of you as a developer. Once your applications works fluently and gives your users intuitive feedback, you need to spend much less time for the user support and you’ll have much more time for your most important tasks.

One way to increase the usability of your application is to avoid pop-up windows altogether and instead display contextual error-messages in-place as close to the actual point-of-problem as possible. For example, when you have a user editable string control, your application should display the error message right next to the string control and instruct the user right away fix the problem occurred.

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Have you been thinking of moving to subversion to manage your source code but don’t want to set up your own subversion server. Subversion has become a de facto standard among LabVIEW developers around the world as a source code control solution. Weather you are a lonely developer or leading a large group of developers, source code control hosting service might be the best solution for you. Using a managed subversion hosting service is cheap, and you don’t have to consume your valuable time in setting up and maintaining the subversion server.

There are several subversion hosting services out there. I’ve been using for the source code of my personal LabVIEW projects and other software projects service provider called ProjectLocker. For merely $2.50 a month ProjectLocker provides a managed subversion service for my projects as well as Trac issue management tool. This cheapest ProjectLocker service package is suitable for personal development projects but they also have bigger packages for larger groups. The price per user for all packages ranges from $1-$2,50 per month, which is hardly nothing compared to the value of having a managed source code control service together with an issue management service. ProjectLocker promised to offer ExpressionFlow readers the first 30 days free on a subscription to any of their services by entering “LABVIEW” in the Promotional Code field at signup.

If you have been hosting your personal subversion repository on your local hard drive, you should consider hosted subversion service. With local repository you are tied to a single computer. Hosted subversion service allows you to work from anywhere and from any computer on your projects. If your company is hosting its own subversion server, external subversion hosting could be a cost-effective and easy alternative. If you or your work group is not yet using source code control, you should no longer have any excuses. Source code control is a must have tool in professional LabVIEW development and using a subversion hosting service makes the first steps very easy.

Don’t forget our earlier article Using new LabVIEW Merge Tool LVMerge With TortoiseSVN. Also check ThinkingInG subversion resources.

EDIT: I found a comparison chart on subversion hosting providers. Don’t read the chart literally, as most providers do have multiple products and not all products are listed. Rather take it as a list of subversion hosting providers aand check yourself what kind of solutions they provide. Not that many subversion hosting companies provide services for open source projects only.

I’m very excited to announce a new ExpressionFlow Studio video series that will concentrate on LabVIEW software development. The first episode starts an ExpressionFlow Studio series introducing to LabVIEW object-oriented programming. The topic of the day is introducing the concepts of objects and classes.

Download Drawing Tool example presented in the video

There are numerous reasons why you would like to allow your LabVIEW application to be extended with plugins. First you may want to allow your customer or a third party to add some new functionality to your application. LVOOP plugins provide a way for you to allow third parties to extend your application. Second you may want to separate the built and development process of the core application from the development process of the features of the applications. With OOP projects LabVIEW development environment slows down dramatically as the number of classes gets too high. It may be wise to separate your application so that only the core elements form the main application and all other elements are provided as add-on components. Third you may want to control the memory footprint of your application and specify at runtime which components are loaded into memory; there is no need to keep the code for unused features in memory. Consider for example that your application supports multiple file formats or device drivers. You can load the needed file format plugins or device drivers on demand into memory at runtime. more…

I started to write this article in June 2007 and a recent post on LAVA made me realize that it may still be of use

National Instruments (NI) has provided LabVIEW developers native OOP support (LVOOP) since LabVIEW 8.2. Users of LVOOP can quickly build single inheritance ByValue object hierarchies that are very powerful. However, there are a few corruption issues related to LVOOP that have made me realize that without SCC I would be getting nowhere on my current LVOOP project. I think these principles also apply more generically to all LabVIEW project files.

There are several hurdles that will basically ruin your day when developing in LVOOP without a good backup system in place. SCC systems provide backup and version control for all of the files that you modify during the course of development which allows you to revert your code to a known state when your files get corrupted. SCC systems basically allow you to take snapshots of your project so that you can revert your code at a very granular level should the need arise. Using SCC should be important to anyone who wants to be able to work on code which means this document applies to solo-developers and not just people working on development teams. There are no excuses for not using an SCC system!

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I’m giving a presentation on LabVIEW Object-Oriented Programming at NIDays 2008 in Helsinki today. The presentation is titled Software Development with LabVIEW Object-Oriented Programming. The slides for the presentation as well as the presentation related example application can be downloaded below.

Download NIDays 2008 Presentation Slides

Discussions in English | Finnish

I’m very excited to announce, that to celebrate its first anniversary, ExpressionFlow opens discussion forums in affiliation with the world’s number one independent LabVIEW community LAVA (LabVIEW Advanced Virtual Architects). The new forums will provide ExpressionFlow readers a rich environment for lively discussions and a convenient channel for ExpressionFlow product related support requests.

All our readers can participate in discussions on ExpressionFlow forums. A free LAVA user account registration is required. Anyone with an existing LAVA user account can already participate in the discussions on the forums.

To navigate to the ExpressionFlow forums, click on the forums tab on the top menu just below the ExpressionFlow logo. I welcome all ExpressionFlow readers to participate in the lively discussions on the ExpressionFlow forums.