Cool Stuff: Transitive Emulates Server Platforms on Other Iron

by Timothy Prickett Morgan

What if you could run Linux, Unix, and mainframe applications on the same box? What if that box could be powered by Itanium, Opteron, X86-X64, or Power/PowerPC processors? This would be pretty cool, right? And it would definitely shake up the server market. Well, a nearly magical piece of software called QuickTransit, created by a little known company called Transitive, does just such a thing, and that software is poised to change the server market in a big way.

Transitive actually launched QuickTransit last September, but the product has only come to my attention because server and workstation maker Silicon Graphics is using it to support applications developed long ago for its Irix-based MIPS workstations and servers on a new line of Linux-Itanium workstations called the Prisms. SGI knows that ISVs and companies that developed their own applications cannot necessarily afford to port those applications to Linux and Itanium. SGI wants to sell new workstations, and the only way it will be able to do that is to license QuickTransit from Transitive to demonstrate to customers that the software works and that they do not have to port their applications, but can rather run them in emulation mode. You might have also heard about a new technology that Apple will be using to support PowerPC-based Mac applications on its future Intel-based machines, called "Rosetta." This is, in part, based on QuickTransit as well. (See the separate story in our sister newsletter, The Unix Guardian for more on Apple's move from PowerPC to X86/X864 chips.)

I feel somewhat remiss about not reporting the initial Transitive launch last September, but I was in the middle of converting our old Midrange Server site to the new IT Jungle site, and somehow I didn't hear about this. But, I have heard about it now, and the advent of the QuickTransit software presents some interesting possibilities. Let me explain where Transitive came from and how it is attacking the market and then you will see why this is, somewhat unfortunately, true. But first, a little history.

While at Cambridge University seven decades ago, Alan Turing proved that in theory you could emulate any computer on any other computer. (And there were not even, strictly speaking, computers yet!) Turing went on to build the Colossus code-breaking computer during World War II and followed up after the war with a professorship at Manchester University, which is in the city in the United Kingdom that also bears that name. Only during the past several decades, as computers have become more powerful and flexible, has it been even possible to contemplate running applications in emulation environments. Most of us have heard of emulation environments, and some of us have used them either at work or at home. I used the Windows 3 emulator inside OS/2 Warp for a bit; Insignia Solutions sold the SoftWindows 95 emulator; Linux has the open-source Wine emulator for Windows apps; DEC created FX!32 to run 32-bit Windows applications on 64-bit AlphaServers; HP is currently using the "Ares" emulation environment to run PA-RISC applications on Itanium (and it is very clever, by the way). And the two things that can be honestly said of emulation environments is this: the performance is generally terrible and the compatibility of the emulated environment is rarely 100 percent perfect. This, quite obviously, puts a significant damper on the whole idea.

Back in 1995, Alasdair Rawsthorne, a computer science professor at Manchester University and a processor designer well acquainted with deconstructing programs at runtime and optimizing them, gathered up some students and decided to take a whack at the software emulation problem. And they came up with a way to modularize the emulation problem in such a way that they could not only improve the level of emulation, but also make it so they could support multiple platforms with their emulation. The result of that work is QuickTransit. After five years of development, Transitive was formed in October 2000, and after three rounds of venture capital financing (bringing in $24 million), the company delivered QuickTransit a year ago and it is making headway in getting some traction in the market. The company is headquartered in Los Gatos, Calif., where it has seven employees, plus a development center with 60 engineers back in Manchester.

There are four flavors of Transitive's emulation software:

• QuickTransit for Itanium: supports MIPS, Power/PowerPC, X86, and mainframe binaries
• QuickTransit for Opteron: supports MIPS, Power/PowerPC, and mainframe binaries
• QuickTransit for X86: supports MIPS, Power/PowerPC, and mainframe binaries
• QuickTransit for Power/PowerPC: with support for MIPS, X86, and mainframe binaries

QuickTransit has three key parts: a front end where the binaries written for one platform (for instance, AIX applications running on PowerPC servers) reside and a back end that links to the new platform, which might be Linux running on Itanium. Sitting between this front end and back end is an optimizer layer that translates blocks of instructions in the AIX-Power application into an intermediate form, which Transitive calls intermediate representation, or IR. The optimizer, as the name suggests, performs optimizations on these blocks of instructions and stores these routines in the cache of the server, in the case the Linux-Itanium box. The optimizer then encodes the binaries for the new target environment and handles all of the operating system and graphics mapping calls, which allows the application to run. Bob Wiederhold, president and CEO at Transitive, says that QuickTransit can support any operating system that is Unix-like or Linux-like as a source application platform and move it to any other Unix-like or Linux-like platform; also, the software can move any applications (including the operating systems) that run on IBM mainframes to an Unix or Linux platform.

Wiederhold says that Transitive is not looking to sell QuickTransit directly to end users--unless they happen to have really deep pockets. Transitive's business model is to sell the software to companies that make gaming consoles, various consumer electronics, embedded systems, and desktop, workstation, and server makers who are all facing, in one way or another, a legacy software lock in for operating systems and their applications. Because of this lock in, ISVs cannot move their code to the platforms the market wants, and server makers cannot endorse a new hardware technology because they are restricted by their software and the platform that it is tied to.

QuickTransit is not actually magical, warns Wiederhold, so not every application can be moved from one platform to another. There are some software functions, for instance, in Irix that simply do not exist in Linux, and there is no way to map these. So the OEM customer who is going to buy QuickTransit to embed it in their devices has to do a prototype development test, which costs $250,000, to check for such things. Then, the OEM has to pay a one-time technology licensing fee of many millions of dollars for each processor/operating system pair within each product line. (In other words, if you have two product lines and four processor/operating system combinations, you pay eight times.) The software also has annual usage fees in the range of millions of dollars per year and annual maintenance fees on the order of hundreds of thousands of dollars per year. You can see that the venture capitalists are pretty keen on getting their bait back. And Wiederhold scoffed at the idea of selling to users or taking the product open source, where Transitive could create a whole lot of trouble.

While the software does not yet support Sparc or PA-RISC applications from the Unix platforms of Sun Microsystems or Hewlett-Packard, Wiederhold concedes that "there are some big opportunities there." Windows is not supported today, and neither is OS/400, but Rawsthorne says there is no reason that OS/400-Power applications would not run within QuickTransit, which means OS/400-based software can be ported to Itanium, X86, or Opteron--if IBM wants to do it. This would be a great way to get a puppy iSeries server that sells for $2,500 and $5,000 to attack the SMB market for real.

Rawsthorne and Wiederhold were perfectly silent when asked why, given the vast installed base of Sparc and PA-RISC iron and disgruntled users on those boxes, Transitive would work on the IBM Power platform first. This may be because IBM approached Transitive first to encourage them to do this, which seems unlikely unless you think about how IBM might want to port mainframe applications to future Power6 servers. Maybe this is how IBM will do it--if it consolidates the mainframe onto the Power platform at all.

As for who is using QuickTransit, only SGI has come forward and admitted it thus far. But Wiederhold says that six of the eight top computer companies are looking at it right now. Any vendor with a big legacy platform has to be interested--period. "No one wants to be on the front end of this," explains Wiederhold, "and everyone wants to be on the back end." That sentence had a nice double entendre to it, meaning no vendor wants to be the first to use the software and concede a kind of defeat, and no one wants to be the platform that end users are moving away from.

Still Rawsthorne is hopeful about the prospects of QuickTransit. "I think people have had 30 years of bad experience with emulation technology, so they will have to evolve," he explains. "But as this technology gets demonstrated, QuickTransit will be something that vendors will not hide, but emphasize."