Comair System Crashes; Passengers Stranded

Fire away! by weeksie · 2004-12-25 23:11 · Score: 5, Funny

Anybody know what they were running? I'd like to see this flamewar get started as soon as possible.

Re:Fire away! by mirko · 2004-12-25 23:16 · Score: 5, Insightful

There recently was a big card problem here, in Europe.
It did not come from a peculiar OS but just because a partition got filled by index tablespace extents.
So, it could just be that they ran out of place and it froze the whole application.

--
Trolling using another account since 2005.
Re:Fire away! by [Xorian] · 2004-12-26 05:56 · Score: 5, Informative

Someone from Comair (who shall remain anonymous) provided me with some details whch people here would be interested in:

The computer system in question runs AIX. The box itself is still up and running just fine; this is purely an application error. This application was not written in-house at Comair, but by another large aerospace company -- SBS (http://www.sbsint.com/, owned by Boeing.) This bit of software does not use an external database, it tracks everything itself. It is a dedicated system responsible only for flight crew assignments. (The blather in the original submission about passenger reservations is way off-base. Those functions are handled by a completely different system.)

The great majority of Comair's traffic flows through the midwest, and the central base of operations is in Cincinnati. The midwest was hit by a major snowstorm this week, causing many, many crew reassignments. It appears right now that the application in question has a hard limit of 32,000 changes per month (ouch). Consider that Comair runs 1,100 flights a day and there are usually 3 crew members on each aircraft. A big storm like this can cause problems for days after the snow stops falling. That's a whole lot of crew changes.

In Comair's defense, this has never happened before and is unlikely to happen again. The crew system was already on the chopping block long before this incident, with its replacement scheduled to go live in January. If this freak storm had happened a month later, this likely never would have occurred.

--
CVS is teh suck. Use Vesta instead.
Re:Fire away! by [Xorian] · 2004-12-26 06:21 · Score: 4, Informative

Just to be absolutely clear: I've only ever communicated with this person on-line, and I can't verify who they are in real life or that they actually work for Comair. It seemed credible though, and it seemed worth posting to de-bunk the slashdot knee-jerk reaction of blaming Microsoft. To me, an application using a 16-bit integer for something seems like a very likely explanation.

--
CVS is teh suck. Use Vesta instead.
Re:Fire away! by Anonymous Coward · 2004-12-26 06:48 · Score: 5, Informative
If it was the crew scheduling system, and it was SBS's Maestro Crew scheduling system, I can fill in some details.
Maestro is delivered on AIX, uses a rather old version of Informix for it's database, and is tied together using the TUXEDO TP monitor from BEA.
The business logic is written in C, and abstracted away using Tuxedo.
In the case of a major schedule disruption, this program isn't responsible for "solving" the problem, but is responsible as being the system of record for holding the new crew schedule.
My guess is that the changes to the crew schedule were large enough that some piece of the system was overwhelmed. ( For example, a transaction that was too large and overran the rollback buffers in Informix ).
Without the system of record in place, a manual process would be very difficult. You would have to figure out:
- Which crews where in which locations
- What aircraft each crew member was qualified on.
- How long they had flown already that day. ( Legalities about how much time you can fly before you need mandatory rest )
- Which routes to send those crews on
- How to get the crews back to a specific city to run the next day's schedule
Of course, any mistakes you made doing this manually would overflow into other systems. For example, you might send an aircraft that's due maintenance to a city with no maintenance facilities.
Also, for those that were critical of the system not being highly availble...this doesn't sound like the kind of problem that HACMP and replicated databases would have helped. The hot standby would have choked at the exact same point.
Re:Fire away! by Daa · 2004-12-26 07:41 · Score: 5, Informative

just to give you an idea, here is the applicable FAA reg for crew scheduling, and the pilots contract may have additional terms that must be met.

121.471 Flight time limitations and rest requirements: All flight crewmembers.
top

(a) No certificate holder conducting domestic operations may schedule any flight crewmember and no flight crewmember may accept an assignment for flight time in scheduled air transportation or in other commercial flying if that crewmember's total flight time in all commercial flying will exceed--

(1) 1,000 hours in any calendar year;

(2) 100 hours in any calendar month;

(3) 30 hours in any 7 consecutive days;

(4) 8 hours between required rest periods.

(b) Except as provided in paragraph (c) of this section, no certificate holder conducting domestic operations may schedule a flight crewmember and no flight crewmember may accept an assignment for flight time during the 24 consecutive hours preceding the scheduled completion of any flight segment without a scheduled rest period during that 24 hours of at least the following:

(1) 9 consecutive hours of rest for less than 8 hours of scheduled flight time.

(2) 10 consecutive hours of rest for 8 or more but less than 9 hours of scheduled flight time.

(3) 11 consecutive hours of rest for 9 or more hours of scheduled flight time.

(c) A certificate holder may schedule a flight crewmember for less than the rest required in paragraph (b) of this section or may reduce a scheduled rest under the following conditions:

(1) A rest required under paragraph (b)(1) of this section may be scheduled for or reduced to a minimum of 8 hours if the flight crewmember is given a rest period of at least 10 hours that must begin no later than 24 hours after the commencement of the reduced rest period.

(2) A rest required under paragraph (b)(2) of this section may be scheduled for or reduced to a minimum of 8 hours if the flight crewmember is given a rest period of at least 11 hours that must begin no later than 24 hours after the commencement of the reduced rest period.

(3) A rest required under paragraph (b)(3) of this section may be scheduled for or reduced to a minimum of 9 hours if the flight crewmember is given a rest period of at least 12 hours that must begin no later than 24 hours after the commencement of the reduced rest period.

(4) No certificate holder may assign, nor may any flight crewmember perform any flight time with the certificate holder unless the flight crewmember has had at least the minimum rest required under this paragraph.

(d) Each certificate holder conducting domestic operations shall relieve each flight crewmember engaged in scheduled air transportation from all further duty for at least 24 consecutive hours during any 7 consecutive days.

(e) No certificate holder conducting domestic operations may assign any flight crewmember and no flight crewmember may accept assignment to any duty with the air carrier during any required rest period.

(f) Time spent in transportation, not local in character, that a certificate holder requires of a flight crewmember and provides to transport the crewmember to an airport at which he is to serve on a flight as a crewmember, or from an airport at which he was relieved from duty to return to his home station, is not considered part of a rest period.

(g) A flight crewmember is not considered to be scheduled for flight time in excess of flight time limitations if the flights to which he is assigned are scheduled and normally terminate within the limitations, but due to circumstances beyond the control of the certificate holder (such as adverse weather conditions), are not at the time of departure expected to reach their destination within the scheduled time.
Re:Fire away! by Anonymous Coward · 2004-12-26 08:24 · Score: 5, Informative

No. It is the version of SBS that pre-dated Maestro. It was brought into Comair in the early 1980's. It's written in FORTRAN and uses whatever record managment system that came with the compiler.
As such it used some very interesting data representations. For example, it tracked time using julian minutes. There are 44640 minutes in a 31 day month. That's small enough to fit in a 16-bit unsigned variable. This approach, nearly taboo by modern standards, was a God-send during Y2K. The system never needed to know what year it was. It became the running wisecrack, "You can't have a Y2K problem if you don't have a 'Y'".
The Aircraft to Flight assignments is another system, but the two share information.

Happens all the time... by Anonymous Coward · 2004-12-25 23:12 · Score: 5, Interesting

When I lived in Chicago, they would lose their radar system on what seemed like a strong wind. And I got stuck in Denver overnight once because the computer system they use to calculate the weight of departing flights crashed. I have a feeling these kinds of crashes are much more common than most people think.

Re:Happens all the time... by hughk · 2004-12-25 23:39 · Score: 4, Informative

I have a lot of friends working at a large airline.
Yes, but it is mostly recoverable. The heavy iron handles things like backend reservations, checkin and cargo. Smaller systems handle things like weight/balance and fuel and PCs are typically used for the front-ends.
Weight/balance calcs can be done more or less by hand if necessary, however a larger fuel margin is needed. Checkin can be done by hand (you have seen those sticky label systems). However to lose reservations is a major problem.

--
See my journal, I write things there
Re:Happens all the time... by Greyfox · 2004-12-26 01:07 · Score: 4, Interesting

From looking at the various terminals that the airline people use, I suspect that most of those airline systems are held together with duct tape and library paste and no one really understands how the whole system works anymore. We see that a lot in non-IT industries (And a few IT ones, too.) Of course, the folks using the IBM ones are not ever supposed to go down...
I moonlighted as an AS/400 operator for a cruise line for a while. We had the system go down once because the janitor turned off the air conditioner in the closet the AS/400 lived in. They didn't dedicate a more secure facility for the computer because the computer wasn't demonstrably central to how the company made money. Turns out they couldn't launch a ship without it. Oops. I suspect that mentality is also prevalent throughout the non-IT industries. They don't know how important their computers are to their business models until those computers die on them.

--
I'm trying to teach myself to set people on fire with my mind... Is it hot in here?
Re:Happens all the time... by TopShelf · 2004-12-26 03:47 · Score: 4, Funny

I used to work with a guy who at one time was an HP3000 operator back when those things were as big as your average washer/dryer combo. His shop had about a dozen of these things, and one night he and a buddy were playing frizbee with the circular write-protect rings that were used on the reel-to-reel tape drives.

Sure enough, his buddy whipped one at his head, and as he ducked out of the way, he fell back and by accident hit the power switch located on the back of one of the HP3000's. In an instant, all the ticket terminals for one airline (I can't recall which one) at O'Hare airport went down, prompting a frantic call from VP's wondering what disaster had struck. So who knows what could have happened this time around...

--
Stop by my site where I write about ERP systems & more

Official my arse... by Omicron32 · 2004-12-25 23:14 · Score: 4, Insightful

Sounds like my Mother wrote the official statement. A techy would never report something in that way.

Besides, it's pretty obvious their OS wasn't digitally signed. :p

My theory? by Ckwop · 2004-12-25 23:18 · Score: 4, Funny

The janitor pulled out the plug for the mainframe and used it to drive is floor polisher..

Simon.

Re:My theory? by rlauzon · 2004-12-26 00:45 · Score: 5, Funny

Probably not. It's an old story (quickly retold):

Army base computer going down every night. So the grunt in charge of it stayed the night to see what was happening. When the computers went down, he heard the hum of the floor buffer.

The janitor had plugged his floor buffer into the same power as the computers and it caused the crashes. It was quickly fixed by telling the janitor to not do that and putting locking covers on the power outlets.

But they dreaded telling the base commander what the issue was. So they told him it was "a buffer problem."
Re:My theory? by jridley · 2004-12-26 04:49 · Score: 5, Funny

A friend was sysadmin at a manufacturing plant, and the janitor kept plugging into the power conditioned sockets with a very large, power-hungry floor polisher. He was actually blowing power supplies. Every one cost several thousand dollars in service calls to replace the power supply and downtime.

My friend put "COMPUTER USE ONLY" stickers OVER the power-conditioned sockets. The janitor ripped them off to plug in, and blew another power supply.

My friend finally confronted the janitor, who was a really obstinate PITA. He stood there and said "Yeah, I did it, and I'm gonna keep doing it, and I don't give a damn about you or your fu*kin' computers."

This was a automotive union shop, very difficult to get people fired.

But, in a show of karma rarely witnessed by mortals, the VP of the division was standing within earshot but out of sight. When the janitor finished saying he didn't give a damn that he was costing the company $10,000 a week because he was too lazy to go get an extension cord, the VP walked around the corner and said hi. I don't know whether the guy ran to his car or the VP kicked his ass right over the top of it.

stating the obvious by Anonymous Coward · 2004-12-25 23:20 · Score: 5, Insightful

"Does anyone know what platform their system was based on? What kind of system just totally crashes?"

A stab in the dark here but I'm assuming a system without foresight and redundancy?

It was running on SCO Unix... by bani · 2004-12-25 23:23 · Score: 4, Funny

They obviously didn't take mcbride's "license or we will have you shut down" threats seriously enough.

blaming the system can backfire by ext42fs · 2004-12-25 23:24 · Score: 5, Insightful

It's not the OS, it's the people behind who's to blame. Yes, stupidity and MSW often go together but in a few years one will probably occasionally see a massive linux outage due to... similarly stupid people.

This is getting a little to common for them. by jhobbs · 2004-12-25 23:25 · Score: 4, Interesting

Back on May 1st of this year Delta's internal traffic monitoring system grounded them worldwide when it was hit by a worm (forget which one). Yours truly was flying that day. I spent 7 hours on a runway in Cleveland. (Talk about adding insult to injury.) Comair is a regional carrier of Detla's. I wonder who handles Delta's IT needs?

Re:Scalability and Twelve Step TrustABLE IT by hughk · 2004-12-25 23:49 · Score: 4, Insightful

No, its more difficult in the airline industry. The system by default tries to keep as many planes in the air earning money as possible. If you have an outage which disrupts this choreography, there is a tremendous knock-on effect as passengers/urgent cargo must be rebooked.

I have seen the major hub for an airline closed because of snow for just a couple of hours in the early morning, but the resulting chaos of rescheduling/rebooking caused the reservations system to crash after just a few minutes of uptime. The same would keep happening after restarts.

It is normal to test system up to several times normal load, but they were seeing peaks at over 100x. The old, 3270 emulator based system would have slowly got through it but the newer system died.

--
See my journal, I write things there

Crew assigment is a hard problem by rsilva · 2004-12-25 23:59 · Score: 5, Informative

'There was a cumulative effect with the canceled flights and trying to get crew assigned that caused the system to be overwhelmed.'

I am only trying to make sense out of the above comment from the official statement above.

Crew assigment is a hard problem, it is usually an MILP (Mixed Interger Linear Programming) .

Such problems may be very hard to solve in reasonable time. Maybe (I'm shooting in the dark here) the first delays made the crew assigment problems grow too large for being solved in reasonable time.This would generate a snow ball effect as the assimgment problems would keep on growing maing the system "crash".

We may never know what really happened but this would be a nice example for my classes :-)

Re:Crew assigment is a hard problem by coyote-san · 2004-12-26 03:06 · Score: 4, Interesting

It's far harder than that alone since you also have to get the aircraft back to the right city (many are in the wrong city due to airport shutdowns due to the weather). Obviously you want to optimize the number of passengers carried along for those flights, but at the same time you'll be "burning" allowed worktime for the crew.

Even worse the crew and aircraft are independent variables. Obviously you need a crew to operate a flight, but the crew may end up in the "wrong" city for the usual schedule. It may be better to leave a plane on the ground and fly its crew "deadhead" to the "right" city than to have them fly a load of passengers to the "wrong" city.

There are reasonably efficient algorithms to solve these problems, but we spent most of my entire second-semester graduate-level algorithms class studying them (network flows). The algorithms most developers would come up (including me after a decade of experience and graduate-level algorithm class) are extremely inefficient and scale horribly.

The bottom line is that it's easy to imagine a system that has no problem with pertubations from the regular schedule but is totally overwhelmed when starting from scratch. I hope the bean counter who saved the company a few bucks by insisting on far more modest hardware gets canned for his costly lack of foresight, but we all know that IT will catch the heat.

--
For every complex problem there is an answer that is clear, simple, and wrong. -- H L Mencken

30,000? by __aafkqj3628 · 2004-12-26 00:22 · Score: 4, Funny

30,000 passengers? Getting dangerously close to an integer overflow there.

Re:30,000? by edp · 2004-12-26 04:47 · Score: 5, Funny

"30,000 passengers? Getting dangerously close to an integer overflow there."
That is not a bug but an accurate model of reality. When you strand 32,768 passengers, they will turn negative.

System Tracked Crew Location, Not Reservations by reallocate · 2004-12-26 00:38 · Score: 5, Informative

Of course, a techie didn't write the PR release. Who in their right mind would let a techie anywhere near a PR release?

BTW, Comair, a Delta feeder headquartered outside Cincinnati, says the system that crashed was used to monitor crew locations and track working hours to ensure no one went over the legal maximum. Comair says the system crashed as a result of massive crew rescheduling following a record snow in their service area on Wednesday. There is no backup.

--
-- Slashdot: When Public Access TV Says "No"

Re:System Tracked Crew Location, Not Reservations by Pharmboy · 2004-12-26 01:30 · Score: 4, Funny

You know, I have my OWN reservations about flying on an airline when they have no backups and can't keep their computers from crashing. Whats to keep their planes in the air?

The last thing I want to hear at 30k feet is that my current flight has been cancelled...

--
Tequila: It's not just for breakfast anymore!

Re:Travel tip by xlation · 2004-12-26 00:42 · Score: 5, Informative

From: http://www.fly.faa.gov/FAQ/faq.html

The term "Rule 240" refers to a rule that existed before airline deregulation. There is no longer an actual Rule 240. The term, as it is now used, refers to each airlines "conditions of carriage" policy. You would need to contact the airlines to obtain this.

whole story? by confusion · 2004-12-26 00:51 · Score: 4, Informative

This comair story is all I'm seeing getting press. I think its a lot bigger than that.
My sister flew Delta on Dec 23rd from Detriot to Atlanta. Plane was 2 hours late, but no big thing. Waited 5 hours for her luggage, with no dice. By the time we got in line for luggage services, there were at least 600 people in the line already.
Talking to other passengers from 10+ different flights from different cities, no one got their luggage that night. Apparently, it wasn't just Atlanta - the local news in Tampa and Detroit had segments on how the airports had taken over parts of taxiways to sort through seas of bags that didn't make it on to planes.
It's been 2 days, and Delta has no idea where the stuff from that flight is. I'm guessing it isn't just Comair that got hit by some computer problems.

Jerry
http://www.syslog.org/

Re:whole story? by garcia · 2004-12-26 01:32 · Score: 4, Interesting

Personally I think that Delta was being a bunch of assholes about the whole thing...

Seeing that my 7pm flight was cancelled for the 23rd I spent 20 minutes redialing from two different phones until I got past a busy signal. After 50 minutes on hold I got through to a representative who scheduled me for the 24th's 7pm flight. I spent the rest of the time rearranging time off from work, the dog's time to be spent at the kennel, car rental stuff, and phone calls to my fiance who would meet me at the airport, and to family we were supposed to see.

At 7am on the 24th the flight was already cancelled. At this point I didn't give a shit anymore. Delta was saying I would have to use my tickets by the 15th of January because "it wasn't their fault". I knew it wasn't the fucking weather down there as plenty of people were saying it was fine in the area. So I call again and get through after redialing for 65 minutes. I get through to a rep after 50 more minutes in queue. She tells me she can't do anything but schedule me for the 25th at 7pm so I'd have to get in queue for the reissue desk. Fine...

After 2 hours and 11 minutes in queue (with no hold music or sound for that matter) someone calls on my home line at 5:15pm from Delta to tell me my 7pm flight is cancelled (cute, I would have been at the airport by then). I tell that rep to get me into the reissue queue as I've been on hold with them for 2 hours.

I finally get through and tell them I want my money back. They tell me I need to speak to customer service. After waiting on hold (with the reissue rep) for 25 minutes the reissue rep offers to refund my money.

We can't fly out for New Years as the kennel is booked and I'd feel horrible asking someone to watch our dog in our house for me than 1 night. So basically we have to wait quite some time to fly down there again.

It was a little bit of a pain in the ass to wait on hold and be jerked around for two days for something that was their fault when they continually claimed wasn't. BAD WAY TO TRY AND PLEASE A CUSTOMER.

Thanks for ruining our Christmas.

Not surprising, coming from Comair by Anonymous Coward · 2004-12-26 00:54 · Score: 5, Interesting

Some of my co-workers are on contract developing Java software for Comair.

Comair are very tied to particular systems, and don't want to change even when the developers have pointed out problems. Case in point: a J2EE-based employee portal, based on Novell exteNd (Novell Portal Service) and a one-way HPUX server. NPS runs in Tomcat, which is servicing requests (via mod_jk) through Apache. No other application shares the machine, and Comair will only consider vertical scaling, not horizontal.

The application creates at least two threads per connection, and when the thread count goes beyond a relatively low threshold (between 300 and 400), Tomcat deadlocks. It's not because they're running out of space in the allocated JVM heap, and they've tuned mod_jk to allow for heavy load. The current solution is to restart Tomcat when the system locks up.

Novell's support has been less than stellar, so the Java contracting group was informally asked what to do. We had all kinds of useful suggestions, from dumping NPS for another portal implementation, to creating custom thread-pools, to using JDK 1.4 new I/O and a minimally-threaded design, and even using round-robin DNS and a group of independent portal servers to share the load. Comair are wedded to particular minimal cost solutions, however, and it shows.

At least when the portal crashes, it only impacts employees and not passengers.

Read the code, Luke (episode II) by chiph · 2004-12-26 00:59 · Score: 4, Funny

Somewhere deep in the code is a comment that says:

// I don't need to check for this condition because
// my asshole manager Steve Johnson says it'll
// never happen

{friggin' slash - When I say plain old text, I mean plain old text!}

From old information... by gminks · 2004-12-26 01:51 · Score: 5, Informative

According to this article [written in 1995] , Dell and AT&T created a new company called TransQuest Information Solutions.

This article outlines how this joint venture re-vamped Delta's IT systems (again remember, this is 1995):

During 1995 and 1996, TransQuest reengineered Delta's systems to migrate them from Hitachi mainframes running Natural, Adabas, and DB2 to an open systems environment. The new systems are written in C++ and access Sybase databases of reusable and distributed objects. The systems run primarily on Sun, HP and AT&T servers under UNIX with clients running under UNIX, MS-DOS, and Windows. The clients are connected to the servers over high bandwidth TCP/IP frame relay networks.

Job titles for the company's 1,100 computer professionals include Systems Engineer and Software Engineer 1 through 8. Staff members recently developed an aircraft weight balance system that can be accessed by pilots to determine how luggage and fuel have been distributed within the aircraft for balance during a flight. This system was developed in C++ on AT&T and HP UNIX servers and will be available on 40,000 devices to 2,000 users.

The trail runs dry here, job postings stopped around 2001.

Which really raises suspicions that all the code is written and maintained offshore. The question now becomes who is handling this for Delta.

One of Tata's spinoffs, Airline Financial Support Services, is described as

"an example of an external service provider that handles a wide range of back-office functions for the airlines. AFS handles sales, refund, traffic and cargo; performs fare audits; manages yields and revenues by performing departure and post-departure processing checks; books crews; deals with overbooked flights and wait-lists; adminsters frequent flyer programs; draws up flight navigation charts; such as landing or route facility charts; and provides customer care." This according to ebstrategy.com

Wipro handles some of Delta's inbound reservation calls in India and the Phillipines.

In conclusion, it would appear that either Tata's AFS arm or Wipro do the IT for Delta airlines.

Re:Someone's gotta say it... by Antique+Geekmeister · 2004-12-26 01:56 · Score: 4, Insightful

Occasionally, however, the head IT guy gets over-ridden by management or by available finances. I've been there, saying "we need to spend money on this" and having to make do with much less money, or even with a cut in funding. You need to document the problem in advance to cover your ass, and get it in print and saved offsite to protect yourself from that kind of mistake. I've done that, too. It helped protect me from a nasty lawsuit because I demonstrated where I had told a consulting client, in print, when the systems would start failing and the resulting legal liabilities, and gotten it signed by the company notary.

Southwest refuses to drink the Kool-aid by Oswald · 2004-12-26 03:06 · Score: 4, Interesting

This computer problem of Comair's just demonstrates how unworkable the hub-and-spoke system of flight scheduling is. It's a flawed concept, foisted on a naive public by an industry locked in some sort of mass psychosis. In the pursuit of minor economies of scale, the big airlines treat their passengers like packages (hey! it works for Fedex, and their cargo can't even walk itself to the next gate...), treat airport runways and air traffic controllers like unlimited resources, and waste vast amounts of jet fuel. The fact that Southwest Airlines (which does not use a hub-and-spoke scheduling system) is profitable, and the rest of our major airlines are either in, just out of, or about to go into, bankruptcy doesn't seem to dent their thick skulls.

I have watched the operation at Atlanta for over 21 years, and I've seen how cutthroat the competition for a major hub is, but it feels like watching two dogs fight over two bones--you can't tell if they're fighting out of greed or stupidity. Southwest doesn't even fly into Atlanta--they know that only a pyrrhic victory would be possible under those circumstances. Management at the other airlines has been criminally incompetent ever since airline deregulation, but it's the passengers, employees and shareholders who pay the penalty time and again.

Re:Southwest refuses to drink the Kool-aid by Anonymous Coward · 2004-12-26 06:31 · Score: 4, Informative

Actually, the only thing that makes these sort of problems easier for Southwest is the consolidated fleet types. With nothing but 737's, you don't add complexity to the scheduler for things like pilot and f/a qualifications.

What happened to Comair here could happen to just about any airline. There is no comprehensive suite of software that handles crew scheduling, aircraft scheduling, reservations, and the myriad of other functions that are needed to run an airline.

Reservations, for other than tiny airlines, are still managed by large TPF mainframes. TPF is a very "bare bones" operating system that runs on IBM mainframes, and was written specifically to deal with high volume / high transaction rate systems. Personally, I've seen 5 attempts at 3 different airlines to replace it with something modern. ( like Unix with an RDBMS ). Each attempt failed miserably, and the airline went back to TPF. Note that TPF is not MVS, OS/390, or any other more mainstream Mainframe OS. It's purpose built.

Unfortunately, this means that all of the other applications have to interface with TPF via screen scraping. To further compound the problem, no "suites" exist to handle the following functions, so most airlines have to "sew together" best of breed solutions for these basic functions:

Crew Scheduling - F/A's and pilots bid on slots to fly, this system takes those bids and turns it into a schedule.
Aircraft Scheduling - Tracks which tail numbers are flying which flights for the dispatchers
Optimization - Different optimizers to do things like:
- Fuel Tankering - Use the jets as "tankers" so that you buy fuel where it's cheapest for flights later in the day
- Crew Optimization - "Traveling Salesman" type solver to incur lowest labor cost, get crews back to home base, etc
- Schedule Optimization - Use the aircraft in the most cost efficient way to cover all of your scheduled flights.
- Maintenence Optimization - Pull aircraft in for Scheduled Maintenance at the optimum time.
- Reacommodation - When things go wrong ( weather, mechanicals, whatever, pull in all of the above variables to crank out a new schedule, crewing, mx schedule, etc )
Booking Engines, for the internet and reservations agents
Point of Sale and Boarding functions for agents, skycaps, and kiosks
Interline functions where other airlines sell your tickets, and transfers for bagggage, etc

Anyhow, this list isn't comprehensive, but shows enough of the disparate pieces that you can imagine why these "glitches" happen. Very few of the items from the list above come from the same vendor, or even run on the same platforms.

Yep, you are right! by Anonymous Coward · 2004-12-26 06:41 · Score: 5, Informative

Your statements are accurate.

I was a unix sys admin there, but left for greener pastures during the dot-com craze. The non-redundant hardware at the time ran AIX, and had a great support contract from IBM. The SBS application however, always had monthly issues, at least at that airline. They were looking for a replacement then, and I'm not suprised they still haven't replaced it.

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