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				Linkway connects IMAGE to ODBC clients with robust access Database middleware offers both 16/32-bit, serial and network links in standalone product Review by Shawn M. Gordon Distributed access to data is a hot topic, and it’s only getting hotter. You see distributed applications and client-server computing becoming more prevalent, and you want to get in the game. A good generic way to leverage your HP 3000 into this is by using an ODBC driver. ODBC is a Microsoft brainchild that stands for Open DataBase Connectivity. The protocol allows you to select a driver, use a generic data access syntax, then read from and write to the database at the other end. The trick in the 3000 market was getting something to read from and write to an IMAGE/SQL database. HP has offered a free 16-bit ODBC driver for IMAGE/SQL, but never got around to writing a 32-bit driver. With the recently-shipped Express 3 MPE/iX 5.5, HP now offers ODBCLink/SE. But CSL has been offering a 16-bit driver since 1995, and a 32-bit driver more recently. Essentially, CSL’s Linkway product can take any MS Windows-based program that supports ODBC such as Word, Excel, Access or Visual Basic, for example, and set it up to get its data straight from your IMAGE/SQL database. Linkway’s approach requires some magic on your end, in much the same way that ODBCLink/SE does: setting up the SQL part of IMAGE/SQL by implementing Allbase database environments (DBEs) for your TurboIMAGE data. Some products on the market that deliver ODBC connectivity don’t require this step, like Minisoft’s ODBC/32 and M.B. Foster Associates’ DataExpress. Unlike ODBCLink/SE and ODBC/32, Linkway doesn’t rely exclusively on a TCP/IP connection to the host. Linkway also supports serial access, which includes dial-up, as well as X25 connections. How does it work? There are two basic components involved in Linkway. Server-side software runs on the HP 3000, a process typically known as a “listener” because it listens for client requests. The client software is the second component. The CSL ODBC driver needs to be installed on each client PC that wishes to take advantage of the Linkway driver. It’s this piece of software that acts as the generic middleware between the client and the server. Once these pieces are installed, a Visual Basic application (for example) doesn’t need to know it’s talking to an Image database on a serial connection – it’s all handled inside the ODBC driver. Features On the server side of the process there are a number of things to occupy your time, but let’s talk about the features. Once your server is running you have a LINKCTL utility that allows you to monitor and manipulate the server process. Commands for running its processes are shown in Figure 1. By building a message file called LINKLOG in the same group and account where the Linkway server is running, you are able to have a comma-delimited log file generated. Since the file is comma delimited, you can import it into any tool to generate custom reports. By building a message file named LINKMON using the same rules, you get a log of all SQL information. Linkway will also tie into Security/3000 from VESOFT if you own it, to make use of the HELLO procedure exits. This allows you to apply the same granular security to the ODBC connections as you use with your regular user logons. This was a nice, unexpected feature.
		Linkway version A.01.00 Computing Solutions Limited 10 St. Andrews Rd Droitwich, Worcestershire, UK WR9 8DN Phone 44 1905 794 400 FAX 44 1905 794 464 email: information@csllink.com Web: www.csllink.com Linkway includes the 3000-based server software and the ODBC driver that is required for the client PCs. It provides 16- and 32-bit ODBC driver support from Win 3.1, Win 95, and Windows NT applications. Linkway supports serial, remote, and X25 connections in addition to standard LAN connectivity. Enhanced security features are supported through Security/3000 by Vesoft. Linkway for the HP 3000 runs on all HP 3000 Series 900s, MPE/iX 4.0 or later. The software is tier- and user-based, ranging from $2,500 for 8 users on a 918 to $20,000 for an unlimited license on a 996, with discounts for multiple CPUs. Support is 20 percent of the purchase price per year and includes phone-in and electronic support as well as new releases of the software.

Some features specific to ODBC are support for Multi-Tables in a single SELECT statement; Multi-Data source support; and support for Microsoft Query97, which is used by Excel and Word for extracting data from databases. Working with unique keys is a big problem that most users run into when attaching to an IMAGE detail data set. Linkway gets around this problem by allowing you to define a multi-column key which would provide a unique value.

	Figure 2: Using Delphi 3 from Borland to open and view IMAGE tables

Numeric scaling provides for server-side manipulation of integer type data, so that only the result is brought down and translated by the client. The 3000’s internal representation of integers is different from the one used in Windows, so translation has to happen somewhere. Linkway’s process is the most efficient way to handle it.

The list of features goes on and on. CSL is to be complimented for the completeness of their product, and the thought given to maintaining industry standards while taking care to support our beloved HP 3000 architecture.

Installation and Documentation

I was able to get the whole installation off the Internet, which was quite convenient. You unzip some files, and then upload a couple of job streams, stream them, then upload the binary files and stream another job which converts them to standard HP program files. I had a little trouble with this process because of the way Reflection was defaulting the binary files. Once I used FTP everything worked fine. CSL was very helpful in this process and went out of their way to make themselves available, even with the dramatic time difference between England and the Pacific Coast of the US.

The documentation doesn’t waste any time getting down to business. They go through the install and then start you right off doing samples. Unfortunately, there didn’t seem to be a straightforward tutorial guide, so I got a bit stuck getting started. The appendices are very good however, and you get a complete description of every file that is part of the distribution.

The TestDrive

It’s a bit of a trick getting all the components set up and going, but once I did it was pretty nifty. I got the Linkway server running, then used the SQL E

		TERMINATE : Terminate the CSL Server KILL 999 : Kill a CSL Server Son which has PIN no. 999 STOP : Kill all sons and terminate the CSL server SONS : List active Server Son PIN numbers PORT 9999 : Change the Sockets Service (Port) No. from 9000 SERVER USER.ACCOUNT,GROUP : Change the Sockets Service to that for this user CONFIG FILENAME.GROUP.ACCOUNT : Use alternate configuration file from LINKSRV.LINKWAY.CSL for networked HP3000's [Applies to LINKCTL only] Figure 1: Commands to monitor and manipulate the server process

xplorer program that comes with Delphi 3 from Borland to open and view the tables. I went ahead and just used the sample table supplied from CSL. If you take a look at Figure 2 you will see how all aspects of the DBE are available in the left pane, and the data in the highlighted table is shown in the right pane. When I connected to the ODBC source I got the Linkway banner, so I knew it was going to the right place. The response was pretty much instant, so I have a warm fuzzy on the ODBC driver implementation.

As mentioned earlier, you can use multiple connection types: serial, network, X.25, dialup. Figure 3 shows how the configuration screen appears. Basically you can set up an ODBC source for any connection type that you are interested in, and then toggle back and forth between them. This is handy if you are a road warrior with a dockable laptop and need to quickly and easily switch between serial and network connections.

	Figure 3: Configuration screen for multiple connection types

The dial-up connection option is a bit more complex to set up, but CSL is right there, ready to help you get it done right. I was very happy with the quality of their support.

Conclusions

Linkway is certainly a robust product, offering a wealth of connection and client operating system options. Make no mistake, any ODBC product takes a fair amount of thought and effort to set up, configure and maintain. The payoff could be tremendous for you, especially if you want to give end users generic reporting tools such as Crystal Reports or R&R and let them go after your database. Keep in mind that while ODBC supports SQL syntax, and Allbase translates this as best it can for IMAGE, if someone does a wild card search on CUST-NAME, for example, you are going to have a serial read. Maybe a long one. Careful thought needs to go into each client-server project.