When I first started working with the AS/400, we supported two means of providing green-screen access to the server using SNA over Twinax: dumb terminals and PC Support with an emulator card. The fun of dealing with controllers, ports, switches, line terminators, and emulator cards is now a thing of the past for the most part, thanks to TCP/IP. With standardized network communications, you can easily provide IBM i green-screen access to practically all of the operating systems on your network.
A lot has changed since the days of SNA, although I do miss the capabilities of the Twinax printers. And we still have a trusty Twinax terminal as the backup terminal in case we ever have TCP/IP issues, but other than that, the Twinax lines have been removed and the clients are now using TCP/IP to access the IBM i.
This article will introduce you to IBM System i Access emulator alternatives and the operating systems that they can run on. This is the first article in a series that will describe some of the options that I am currently using. The following articles will provide comprehensive details on configuring and installing these 5250 emulators on different operating systems.
I've had the opportunity to use multiple operating systems on my desktop throughout my career. I used UNIX at college. I used the VAX system while employed at Digital Equipment Corporation. But the primary desktop operating system that I have used for development since I have worked on the IBM i has always been the Microsoft Windows operating system...until recently. Now my primary desktop operating system is Linux.
As you start integrating your RPG applications with other operating systems, you start expanding your expertise and want more flexibility to access your IBM i on those operating systems. This article will go over some of the applications that I use and invite an open discussion on other alternatives that you may be using.
I'm sure most of you are familiar with the IBM iSeries Access 5250 emulator. Sam Lennon recently wrote an excellent series of articles for MC Press Online about different ways to "Soup Up iSeries Access" (Part I, Part II, and Part III), and I recommend that you read that series to discover some of the options you may not have known existed.
I'll discuss several alternatives to the IBM iSeries Access emulator, and every one of those alternatives provides a Windows version of the software, so I'll focus my discussion of the details on a potentially less-familiar operating system.
As your RPG applications begin to reach beyond the IBM i, you'll start to learn about different technologies and ways to integrate them with your programs. And what better way to start experimenting with different technologies than Linux? You can download and install on your Linux system a lot of the technologies that are available for the IBM i.
You can dig in as far as you want to (and it's free) without having to worry that your learning curve will take longer than the 30-day trial period and without investing your efforts into program development and then obligating your talents to a technology that you cannot afford to support.
Being an RPG programmer, you will probably want to get a 5250 emulator on your Linux system as soon as possible. You could use Telnet, but that would be cumbersome and would not present your user interface in a manner that would represent your target audience.
Another possibility would be to install Linux and Windows as options for a dual boot on your computer. But once you start using Linux on a regular basis, you may find this an undesirable option to support for the sole purpose of 5250 emulation. You can also install a live version of Linux that you can run directly from a CD or USB storage medium if you want to try it without installing it on your hard drive.
IBM System i Access for Linux
IBM provides a Linux version of IBM System i Access that is available from IBM's Web site. You can download an RPM file that includes a 5250 emulator and the ODBC driver to access a DB2 database. There is an RPM available for 64-bit platforms, but at the time this article is being published, it only contains the ODBC driver.
If you are new to Linux or intend to start using Linux in the near future, then the next article will be a great reference for you because I'll be going into the details of installing the 5250 emulators. So don't worry if you don't understand what I'm saying here about the installation details. An RPM file is a file format that is used for software package management to automate software installations and removal.
tn5250 is the first working 5250 emulator that I used on Linux, and I still use it today. tn5250 runs on Windows and any Linux or UNIX operating system. This application is easy to install and includes freely available technical support via its mailing list. I posted questions, and we started diving right into source code and call stacks. The mailing list helped out with the simpler questions too.
You can download tn5250 from the SourceForge Web site.
One of my recent jobs included providing information to the Internet, which involves other departments to harvest the data. One of these departments is Graphic Design, which notoriously consists of Macintosh users. The idea of putting a Windows computer in a room full of Macintosh advocates for the sole purpose of accessing the IBM i was not an appealing option, so we wanted to provide the capability to access the IBM i using the company's existing machines.
MochaSoft provides a 5250 emulator that you can easily install on Macintosh computers. The technical support is great, and the cost is minimal. At the time that we purchased the software, it was $25 per license.
MochaSoft also provides emulators for Linux, Palm, Nokia 9300/9500, Windows Mobile, Active X Components, Windows, and DOS.
You can download the 30-day trial version from Mochasoft's Web site.
tn5250j is a 5250 emulator that evolved from the tn5250 open-source project. tn5250j is a rewrite of the tn5250 in Java, so you can run it on any operating system that supports Java. This software provides the usual 5250 emulator as well as some additional GUI options.
You can download tn5250j from the SourceForge Web site.
This article is intended to introduce the software emulators that are available, but there are also other options to provide green-screen support to your users.
If you wish to give your users emulator sessions that provide virus protection at minimal cost, you could consider using TCP/IP thin clients. Some of the thin clients that I have installed support multiple emulator sessions, printer sessions, Web browsers, and Java runtime environments--without the hard drive, thereby preventing users from installing additional software and getting viruses.
IBM also provides browser-based access to the System i with System i Access for the Web.
Breadth of Information
This article is intended as an introduction to some of the options that are available. There are a lot of options out there to choose from. I've covered only some of the emulators that I've used, so feel free to share your experiences in the forum.
In the next article, I'll provide detailed installation and configuration instructions for the Linux alternatives that will address some of the most commonly needed features.
Expanding Your Possibilities
When you begin integrating the IBM i with other operating systems, it can seem like a lot at first. But, when you have a few solid leads that give you the familiar green-screen as the results, you'll become exposed to the fun new features that you can play around with. Hopefully, this article has encouraged you to take your first steps into expanding your options with other operating systems.