Clerity, which is based in the Chicago suburb of Oakbrook Terrace, has been doing ports of old Wang word processing systems and HP 3000 MPE-based minicomputers to other platforms, and had approximately 25 employees before buying Sun’s Mainframe Transaction Processing (MTP) and Mainframe Batch Manager (MBM) systems software and middleware for an undisclosed sum.

The MTP software is, in essence, a clone of IBM Corp’s CICS transaction monitor and COBOL environment for mainframes, and MBM is a set of software that can mimic the Job Control Language of a mainframe that runs batch jobs.

Clerity has acquired all of the intellectual property associated with these tools, as well as the 3270 Pathway protocol software, which emulates the green-screen processing of an IBM mainframe, the Web client front end for this software and the toolkit for porting applications and tweaking them to run on a Unix box.

What Clerity also has as part of the deal is 27 out of the 30 employees who supported these products at Sun, which doubles the size of Clerity. Being privately held, Cameron Jenkins, Clerity’s chief operating officer, did not divulge how big Clerity is in terms of revenues. But it is not hard to figure out that there is a lot more money to be made in porting and rehosting mainframe applications than dealing with old Wang and HP minis.

The Sun tools have a long history, and were originally spun out of Bull SA, the French mainframe and Unix server maker, in the early 1990s as a vendor called UniKix. At that time, Unix servers were getting powerful enough to take on more than departmental tasks, and having a clone CISC environment and a relational database allowed mainframe shops to move their COBOL applications to a Unix environment without giving up the way they coded those applications.

In 1997, Fisher Technology Group bought UniKix and ported the code to Windows, and in 1999, PeerLogic, a middleware company located in Silicon Gulch, acquired the UniKix tools to take its run at the mainframe.

In August 2000, as the Internet bubble was bursting, Critical Path, a maker of e-mail and messaging software, acquired PeerLogic for a stunning $416m in stock, but by September 2001, that company was ready, willing, and eager to sell the tools to Sun. At that time, Sun was launching its high-end StarCat 15000 UltraSparc-III servers, and needed a story to tell–any story to tell, since the IT business was in a tailspin–and that story was that it could now take a direct run at the mainframe.

It is safe to say that the UniKix tools have had as many marriages as Liz Taylor.

At the point where Sun acquired the mainframe rehosting tools, 300 companies with 900 installations worldwide had rehosted CICS and other mainframe applications using them. Sun targeted customers with fewer than 1,000 MIPS of processing power in their mainframe complexes because they are easier to take away from IBM than larger accounts.

Sun’s initial run rate for mainframe replacements using these tools was 50 companies a year, and that represented about $50m to $100m in sales for the company, including hardware, software, and services. That run rate dropped off significantly in recent years.

Sun’s approach was to try to get companies to rehost some non-critical mainframe applications–as if such things existed–to test the idea, and then get them to do more. This was smart. The problem was that Sun stopped supporting AIX, IBM’s Unix variant, and HP-UX, Hewlett-Packard Co’s Unix variant. This left a number of customers in the lurch.

It also meant that companies that didn’t want to pay a hefty premium for Sun Sparc/Solaris gear–which was very pricey compared to IBM’s own Power-based pSeries and System p5 servers until this year–did not buy the Sun rehosting solution. Ditto for those who like HP-UX Unix and IBM mainframes. According to Jenkins, a few very large AIX accounts were able to wrangle support out of Sun, but officially, Sun only supported the UniKix tools on Solaris from that point forward.

To Sun’s credit, even with those constraints, it was able to get 85 customers with a total of 1,400 sites to use the UniKix tools and pay for ongoing licenses and support for the software. But, Jenkins is very eager to go back to the 50 customers who are running on HP-UX and AIX at some 300 sites and get them back into the fold using MTP and MBM.

We have been looking to get into this space for some time, said Jenkins. We are big believers in CICS and mainframe-style processing. And now we are taking away the shackles that Sun put on these products.

Sun was interested, obviously, in driving its own platform sales. In its original announcement from 2001, Sun pegged the opportunity at $20bn with its high-end servers and the mainframe rehosting tools, but a few years later, it pegged it at a more sober $1bn opportunity. As Clerity did the deal, Sun had 50 potential customers kicking the tires on the MTP and MBM software.

Clerity has, by virtue of the deal, become a Sun platform partner, and was already an IBM partner. Now, it is opening up a relationship with HP. In fact, since July, Clerity has been working on a port of the mainframe rehosting tools to HP-UX and Jenkins says that this work will be done within a month or so.

Clerity will support HP-UX 11i v2 on PA-RISC and Itanium processors. Support for AIX, which is a key platform for True Blue mainframe shops, which want to move some of their workloads off the big iron and onto cheaper Unix iron, is also on the way. And, of equal importance, Clerity will support Linux platforms, too, which Sun did not.

Linux will be supported on X64, Power, and Itanium platforms, and if Clerity goes so far as to support Linux on the mainframe, this will present a very interesting prospect. Mainframe shops could end up rehosting MVS and z/OS mainframe applications on Linux partitions – on their mainframes.

Clerity does not, by the way, have to stop at the IBM mainframe. Being initially a Bull product, the toolset has features to port GCOS applications running on Bull mainframes and ACOS applications running on NEC Corp mainframes to Unix. The software can also be used to port applications off of vintage Fujitsu Ltd and Hitachi Ltd mainframes.