So, why isn't everyone using IEF today, and if you are of a certain age, why have you not even heard of IEF? CASE tools were a big thing for a while, which means many people liked them and many other people did not. The latter were usually put off by the rigor, they thought they were giving up flexibility. Programmers could be put off by the fear that it replaced what they did, whereas what it did was just move programming up to logical Action Diagrams, just like 3GLs had been a move up from assembler coding.
But two things happened that really killed IEF and CASE as a whole: IBM's AD-Cycle, and ERP systems like SAP.
AD-Cycle: As I said, CASE tools were a big thing in the years around 1990. IEF was only one of many tools you could buy, but the vast majority of the tools only did part of the job, As described in an earlier post, there were modeling tools that analysts would use but went no further; these were called Upper-CASE. Other tools existed that would generate code from some kind of input; these were called Lower-CASE. The Upper and Lower referred to the parts of the lifecycle the tools covered when viewed as a waterfall that went from high (initiate, analyze) to low (design, code, test). After a while, vendors of one kind of tool would partner with the vendor of the other kind of tool, and both would trumpet that you could now do the whole life-cycle if you used their tools together.
Unfortunately, there were so many tools that you could not just pick any two you liked; if you picked one, then only so many other tools would work with it. I suppose somebody though this was a huge problem or opportunity, because IBM (still the big player in the largely still mainframe world of the time) decided they had the solution.
You see, each upper-CASE tool had some kind of repository or encyclopedia to store its models, especially if you created them on a PC, after which you would upload to one repository that all modelers would have access to. Those repositories, like the tools, were proprietary to the vendor. IBM decided it would create one common repository that all tools could use, so you could then use any combination of upper and lower you wanted. Add some services and its own tools, and the whole thing is presented to the world as AD-Cycle. Immediately a whole lot of the most popular tools signed on to the program.
Remember, IEF wasn't upper or lower, it was the whole deal, which was known as Integrated-CASE. Texas Instruments looked at AD-Cycle and said, we like our own repository just fine and we don't interface to any other tools, so you folks carry on and when you have something usable we will consider it. (I am trying to remember if IEW did sign on to AD-Cycle, I think it did but don't recall why.)
The problem was that the AD-Cycle repository was a disaster. Real customers who bought it got something that was huge, slow and not very functional. News got around and sales tanked but, even worse, companies who had not used any CASE tools yet avoided all CASE tools, not just the AD-Cycle repository. The whole tools segment was hit, and this hit home to me when I was attending my second IEF user conference, and the main TI guy for IEF walked up to the microphone and announced that TI had sold IEF to a relatively unknown software tool company. TI was a hardware company, and they just decided a failing software segment was not for them anymore. The new vendor changed the name but eventually was bought up, and up and up, until IEF disappeared into the maw of Computer Associates. I changed companies not too much later (for other reasons), so that was the last I saw of IEF.
But it did carry on, and I think some version of it may still be being used by its original customers, but that was it.
What helped to finally bury it was the parallel arrival of the big ERP systems like SAP. They were selling to management that you could buy SAP and not have to develop anything. So, if you stopped in-house development pretty much cold, why would you buy an admittedly pricey I-CASE tool that was just for development? Well, you wouldn't, and that was that.