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After eight years with Dallas-based Southwest, Director of Reservation and Distribution Technologies Terry Hornbaker said he’s become a believer in the HP 3000. If it appears to be a dramatic shift, it only serves as an example of the flexibility and cost effective attitude at the only airline to show profitable quarters for 24 straight years.

“When I came here, I was Big Blue,” Hornbaker said. “Now I’m being converted to brown,” he added, referring to the color of the nameplates on HP 3000 systems. “When I first assumed this position with Southwest Airlines I had a stated objective of killing the HP 3000,” Hornbaker said. “But, life changes. Five years ago we had one, and I thought it was going to be dead.”

But changes in the airline reservation industry – and a fortunate acquisition by Southwest in 1993 – combined to make the HP 3000 absolutely vital to keeping its 230-plus aircraft filled with passengers flying between 52 United States cities. The fifth largest domestic airline logged more than 2.3 billion revenue passenger miles in December 1997.

Its HP 3000 commitment has grown as well. From a single HP 3000, Southwest’s installation has swelled with plans to have well over 60 systems, including nine in regional reservation centers and eight more in the national reservation core complex, along with an HP 3000 in every airport on the Southwest circuit.

The widely touted ticketless travel application was the airline’s first milestone for the 3000, but the main reservation center set to go online this spring will dwarf the scope of that success. “Southwest embarked on a project to move away from the IBM mainframe to create a system that would meet their needs on an alternative platform at a lower cost,” Hornbaker said, “and the HP 3000 was selected. We can take a network failover or hardware failover and still keep running without interrupting service.”

Hornbaker said he estimates the airline’s investment in the reservation system is 10 times the size of ticketless investments, controlling every seat on every Southwest aircraft. All that reliance on the HP 3000 developed from successfully meeting a need to create a business application in a matter of months.

Cushion change

In addition to a lot of hard work, Southwest’s ability to meet an unseen business need came from good fortune, the kind of serendipity managers hope for in a world of changing business conditions. A few months after Southwest acquired tiny Utah-based Morris Air, the larger airline had to come up with a way to eliminate ticketing on as many of its seats as possible.

Ticketing in the airline industry is served by several reservation networks known as CRS systems, from the largest Sabre to less-comprehensive Apollo, Worldspan and System One networks. Southwest had a formal, paying alliance with Sabre, while the other CRS systems listed Southwest flights for free. In 1994 Apollo, Worldspan and System One sought to transform their complementary listings of Southwest’s flights to paid CRS listings. Keeping an eye on costs to maintain profitability, Southwest chose to tighten its relationship with Sabre and learn to sell tickets without being listed on all CRS networks.

Hornbaker said that a meeting with senior management and Southwest president Herb Kelleher in that year came up with a solution to the problem. The airline would create a ticketless reservation system to keep its flights available to travel agents while dropping off the other non-Sabre networks. The hitch was the ticketless system had to be developed in four months.

At that point Southwest’s acquisition of Morris began to pay off bigger than anticipated. While the airline had bought the smaller carrier for aircraft and route considerations, it also had acquired a less-noted asset – the MARS ticketless application written by Morris IT manager Dave Evans. MARS was written in COBOL for Morris’ HP 3000s.

“In typical Southwest style, I’ve got a napkin on my bulletin board where it all began,” Hornbaker said. “We drew figures of the MARS application connecting via a WAN to our reservation server.” The miracle would be getting it all in step in just a few months, leveraged by the fact that Southwest had one HP 3000 and the MARS code.

“It was one of those things like when you buy a couch and find some money in it when you get it home,” Open Skies’ Evans said. “Right after the sale [of Morris] there was an internal memo from American Airlines’ technology operation – one that stated they thought the reason Southwest bought Morris Air was because of the technology innovations we were making.”

“We showed that to Herb [Kelleher],” Evans said, “and he laughed and said, ‘I had no idea about the system.’ It was one of those things like ‘Hey, we got a bonus.’ ”

Evans began to consult for Southwest to get MARS linked into the Southwest reservation system, and the software went online on schedule in September of 1994. Along the way Evans founded Open Skies to sell a rewritten version of MARS to other airlines, continuing his relationship with Southwest because it was expanding its plans for HP 3000s. Southwest had checked on MPE’s availability references, and found them better than those of Unix solutions.

Online takeoffs

While the ticketless application was a success at Southwest, the main reservation system was still working on the largest 3090 single-processor system IBM sells. The airline’s system was loosely coupled to the HP 3000 ticketless application, but Southwest wanted to revamp it for computing in the 1990s. Like many airline systems, Southwest’s was written to an arcane, 6-bit data standard that was difficult to couple with TCP/IP networks.

Hornbaker said Southwest studied several options for replacing its reservation system. Based on data available during its 1994 evaluation, the choice came down to either an HP-UX solution or one running on the HP 3000. At that time, Hornbaker said Southwest couldn’t find evidence Unix had the kind of availability needed for a 24x7 application like air reservations.

“What was the Unix reputation three years ago? Memory leaks all over the place, and if it stayed up for week it was great,” Hornbaker said. “When you talked to any of the big-time players that were doing anything with Unix, they said it’s not ready for a ‘gotta have it, must be there’ kind of application. If you could cycle it every night, it was great.”

HP helped Southwest with a proposal for either the 3000 or the HP 9000 as a platform for Southwest’s system, but 1994’s notices on MPE/iX were much better than those of Unix. “Three years ago there were memory leaks everywhere [in Unix]. It’s changed a lot since then, but we went back to our bag of known tricks,” Hornbaker said. “One of the solutions in our bag of tricks that we had to consider was the 3000, because we’d already made an additional investment in it for ticketless.”

The airline does use Unix in its operations for financial work, as well as Windows NT as a bridging platform for desktops and browsers. But the HP 3000’s reputation in the mid-90s gave Southwest advantages that couldn’t be overlooked. “It helps reduce my costs, it’s got a high OLTP reputation, and it’s an integrated solution,” Hornbaker said. “If there’s a problem, at most I’ve got three vendors to work with to solve it – HP, Quest [NetBase] and Bradmark [Superdex]. In a Unix solution I’ve got peripheral vendors, hardware and operating system groups, database suppliers and compiler makers. That gets complex.”

Redundancy and tiers

The Southwest system is designed to sell a ticket after several inquiries, so Hornbaker said three tiers of servers are linked together with shadowing and distributed communications. A caller typically makes several probes about a flight before making a choice, so a buffer system handles lots of reads and also keeps the IMAGE database highly available all at once.

“We can’t afford an outage,” Hornbaker said. “We don’t want customers to have to call back, because they may not. The B tiers are primarily designed to reduce the load on the A tiers, and the C tiers help us distribute more of that read activity on non-volatile data to the local box. They also serve as a central processor, to give us up to 5,000 people connected to us simultaneously.”

Southwest is breaking ground with the distribution and shadowing capabilities of the NetBase solution. Hornbaker said Quest is making some custom modifications for shadowing the Southwest A tier system, “to ensure the hot availability on the secondary A box.” While he’s been talking with other large NetBase sites such as Microwarehouse, he acknowledges that “there’s no one we’ve talked to who’s doing [high availability] the same way we’re doing it.”

This dual-master concept that Southwest is spearheading through the NetBase code will ultimately be available to the rest of the Quest customers, according to Hornbaker. The design is making it possible to do logical transactions across multiple databases, the kind of transaction booster that will let Southwest sell more than a two million seats on a busy day.

“If we were to run a fare sale, we could easily reach that number,” Hornbaker said. “Our capacity in our reservation system alone will support 4,000 people. Then we know that we have some special travel agencies and selected companies that book directly on Southwest, and we have to support the demand from the Internet. When we first sized this application we thought we could plan for 3,000 people. Now it’s at 5,000. In a three-year period, that’s how much it’s grown.”

Next issue: how Southwest has designed and built its solution, and how the company positions its HP 3000s with its other computing platforms.