IBM Releases iSeries ODBC Driver for Linux

by Joe Hertvik

IBM has released a beta version of the iSeries ODBC Driver for Linux. The driver provides OS/400 data access for Linux applications using the ODBC API, and is available for Intel-based Linux machines running Red Hat Linux 7.x, SuSe Linux 7.x, or TurboLinux 7.x, and on the iSeries within logical partitions using Red Hat 7.xx.

IBM specifies that you must have Unix ODBC Driver Manager 2.0.11 or higher installed on the Linux client to use the beta ODBC driver. Note that the Unix ODBC Driver Manager is not provided by IBM; it is a free and open solution that can be downloaded from the Unix ODBC Web site.

IBM's Client Access group produced the Linux driver, which is based on the Client Access Express for Windows ODBC driver. As such, you will see some familiar Client Access utility programs packaged with the driver, including CWBPING, for verifying connections to OS/400 host servers; CWBNLTBL, for downloading conversion tables; and CWBCOPWR, for altering communications settings. Another similarity to Client Access is that the Linux ODBC driver is written to the same ODBC API. It also accesses OS/400 data through the same OS/400 host servers as the Client Access products.

But the Linux ODBC driver differs from Client Access Express ODBC in several important ways. The Linux driver is ODBC V3.5 ANSI driver, while the Client Access Express version is an ODBC V3.5 Unicode driver. As a result, the Linux driver doesn't support Unicode strings passed as arguments to the APIs; to use Unicode strings as API parameters, Unix ODBC Driver Manager maps these calls to the ANSI driver interfaces, so there may be some additional overhead here. In addition, the Linux beta driver doesn't support many common Client Access ODBC functions, such as MTS, two-phase commit, APIs that display a GUI, translation DLLs, and DSN connection options for user and password prompting. While these omissions may be discouraging to people who are used to the fairly mature Windows ODBC driver, remember that the Linux driver is only a version 1.0 beta and that IBM will surely add more features in later versions. You won't be able to get everything the first time out of the gate.

Linux ODBC data source names can be configured through an IBM-provided GUI interface, or configured manually through an .odbc.ini file. However, you'll need to become comfortable with the manual configuration anyway, since IBM has indicated that the GUI contains only the most commonly used connection options. To configure all the available ODBC options, you must manually edit the .obdc.ini file.

It's both practical and significant that the driver came from the Client Access group. It's practical because IBM leveraged years of development work in Windows-based technologies to bring OS/400 ODBC connectivity to the Linux platform. So the driver may be more stable than you might otherwise expect from a version 1.0 beta. It's significant because the Linux driver is another step away from the Windows-only view of the world, which the Client Access group has traditionally supported. The first step was taken last year, when the group released iSeries Access for Web, which provides a browser-centric view of OS/400 resources. With the new Linux driver, Client Access is taking a second step by providing Linux-based software for OS/400 access.

Now, you might be thinking that the Linux ODBC driver presages a Client Access Express product for Linux. I asked IBM whether Express client for Linux was in the cards, and IBM replied that it already has a Linux desktop connectivity solution in iSeries Access for Web. According to IBM, it is recommending iSeries Access for Web to Linux users because that software and WebSphere Host Publisher (which also comes with Client Access) both run under the Netscape browser on Linux. IBM further indicated it has been recommending iSeries Access for Web to its own customers, who have tried it and liked it. However, iSeries Access for Web may not be the best substitute for Client Access PC5250, because it has a weak 5250 option based on the old Workstation Gateway interface, which was a marginal Web-based 5250 solution to begin with (see "IBM Releases iSeries Access for Web Beta," August 4, 2001). iSeries Access for Web and WebSphere Host Publisher are pretty much about providing Web-based access to iSeries information, not about 5250 emulation. And iSeries Access for Web also runs under the WebSphere Application Server, which has with a hefty price tag for running on a cheap operating system like Linux. So although IBM is recommending a WebSphere solution for Client Access-like processing, that may not be your best option, and if you're looking for Client Access-like software for your Linux desktop, you might want to check out any of the free 5250 emulators for Linux that are available on the Web.

If you do give IBM's iSeries Linux ODBC driver a try, be sure to drop me a line at jhertvik@itjungle.com and let me know what you think.