Comair System Crashes; Passengers Stranded 398
Broerman writes "30,000 people have had their flights cancelled by Comair this weekend thanks to a computer system shutdown. It appears that due to weather and other problems that flights began to be cancelled on Thursday and the backlog choked the system. 1,100 flights have been cancelled so far, including all flights through 12/26. Does anyone know what platform their system was based on? What kind of system just totally crashes? The official statement is that 'There was a cumulative effect with the canceled flights and trying to get crew assigned that caused the system to be overwhelmed.' It seems highly improbable that a system would crash because it had too many reservations. The system should only be able to hold as many reservations as it has flights/seats. It would seem that it's more likely that the system was overloaded with use and that caused a meltdown. When you add in the problems experienced by US Airways, this hasn't been a Merry Christmas for many."
Fire away! (Score:5, Funny)
It doesn't matter... (Score:2, Insightful)
Re:Fire away! (Score:5, Insightful)
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.
Re:Fire away! (Score:4, Interesting)
Interesting...
Job postings might give some insight: Comair, Inc. jobs [yahoo.com] into what they are using.
Re:Fire away! (Score:3, Insightful)
My preliminary diagnosis: blown rollback segment. With too many flights being cancelled, the simultaneous rescheduling of all those crew resulted in a SQL transaction that exceeded the size of what the DBMS could undo. So an uncommitted statement failed and the application code either was not prepared for such a possibility or could only handle it by timing out. Scheduling tasks could no longer move forwa
Re:Fire away! (Score:3, Interesting)
SQL transactions generally last seconds and involve operations like "open tr, is there space in this flight?, reserve space, close tr". Not "open tr, wait for flight to fill up, close tr". Rescheduling or canceling flights probably isn't accomplished using transactions: it's application level logic.
My personal diagnosis: I think it has nothing to do with the backlog, and that the system just melted under high s
Re:Fire away! (Score:3, Insightful)
Yes, but you pretty much spelled out what my point was in that the n^2 complexity issue is unrelated to transactional operations. That is, a transaction is a transaction, it is scalable, so it doesn't matter whether the actual operation for computing stuff is O(n^2), the transaction is still a fixed cost. On a side point: I don't agree that because the
Re:Fire away! (Score:5, Informative)
Someone from Comair (who shall remain anonymous) provided me with some details whch people here would be interested in:
Re:Fire away! (Score:5, 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.
Yep, you are right! (Score:5, Informative)
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.
Re:Fire away! (Score:5, Informative)
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! (Score:5, Informative)
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 [sita.aero], but the two share information.
Re:Fire away! (Score:5, Informative)
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:AIX? (Score:3, Funny)
So lets think this one through for a second. The people who work there say the system that failled runs on AIX and that its the application thats gone whoopsie. So they obviously must be lying since everyone knows that the minute an application
Happens all the time... (Score:5, Interesting)
Re:Happens all the time... (Score:5, Informative)
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.
Re:Happens all the time... (Score:2)
Re:Happens all the time... (Score:3, Funny)
There's some...thing on the
Re:Happens all the time... (Score:5, Interesting)
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.
Re:Happens all the time... (Score:3, Insightful)
Each time the industry is making money and IT is flush a project is started, to examine all the code in the system and refactor and rewrite to modern
Re:Happens all the time... (Score:5, Funny)
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...
Re:Happens all the time... (Score:3, Insightful)
I'd love to see some uptime numbers for past systems versus the systems we have today. I wonder if t
Re:Happens all the time... (Score:3, Interesting)
I did hear of one company that went out of business because their accounting system was writt
Official my arse... (Score:4, Insightful)
Besides, it's pretty obvious their OS wasn't digitally signed.
Re:Official my arse... (Score:2, Informative)
Its one of SCO's last large scale deployments. You know who to blame now.
Online Anime Gallery's [sharkfire.net]
MOD PARENT UP (Score:2)
System Tracked Crew Location, Not Reservations (Score:5, Informative)
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.
Re:System Tracked Crew Location, Not Reservations (Score:2, Funny)
Re:System Tracked Crew Location, Not Reservations (Score:5, Funny)
The last thing I want to hear at 30k feet is that my current flight has been cancelled...
Re:System Tracked Crew Location, Not Reservations (Score:4, Funny)
The Bernoulli Principle [fiu.edu]. And I don't think computers crashing are going to affect it. This isn't the Matrix, after all.
Re:System Tracked Crew Location, Not Reservations (Score:3, Interesting)
I also don't eat at diners where the help isn't properly groomed. Same principal: if you can't take of simple stuff, you probably can't take of something more impo
Re:System Tracked Crew Location, Not Reservations (Score:3, Insightful)
Perhaps if computer usage/programming had evolved to the level of personal hygenie, namely routine effort anyone could do would prevent computer crashes, your point would be convincing. However, in practice we realize even the best professional programmers make errors even buffer overflows (a
Someone's gotta say it... (Score:3, Insightful)
I don't know. Frankly, it has less to do with the platform than the custom software that runs on it.
Re: (Score:3, Interesting)
Re:Someone's gotta say it... (Score:2)
Re:Someone's gotta say it... (Score:2)
At what point did the head sysadmin become responsible for finding bugs in the code?
Re:Someone's gotta say it... (Score:4, Insightful)
Whether it is the cooling system for the computers, the operating system, the applications or simple hardware issues, it HAS to be the IT Director's responsibility. I mean, who the hell else?
Re:Someone's gotta say it... (Score:5, Insightful)
Bringing the /. effect to the weary masses. (Score:2, Funny)
My theory? (Score:5, Funny)
Simon.
Re:My theory? (Score:2)
Bart & Lisa: PLUG IT IN! PLUG IT IN!
Nerd (Doug): What, the rock tumbler or the TV?
Bart & Lisa: THE TV! THE TV!
(Itchy and Scratchy theme plays, Krusty comes back on)
Krusty: WOW! They'll never let us show that one again... never in a million years!
Re:My theory? (Score:4, Funny)
Re:My theory? (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? (Score:5, Funny)
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 (Score:5, Insightful)
A stab in the dark here but I'm assuming a system without foresight and redundancy?
It's obvouis... (Score:3, Funny)
That doesn't need answering.
Re:It's obvouis... (Score:2)
That doesn't need answering.
Damn! We warned them to test KDE 3.3 out before upgrading!
(Ok, so just more obnoxious than anywhere near fatal)
It was running on SCO Unix... (Score:5, Funny)
blaming the system can backfire (Score:5, Insightful)
Scalability and Twelve Step TrustABLE IT (Score:3, Interesting)
See Twelve Step TrustABLE IT : VLSBs in VDNZs From TBAs [blogspot.com].
and also The ActiveGrid(TM) Grid Application Server [activegrid.com] and Grid Computing [google.com] in general.
Re:Scalability and Twelve Step TrustABLE IT (Score:5, Insightful)
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.
Where did the system fail under stress? (Score:2)
Re:Where did the system fail under stress? (Score:2)
Leasing third party servers for stress testing (Score:2)
Re:Leasing third party servers for stress testing (Score:2)
It is then an issue as to whether you really want to design IT systems for every scenario. It costs a *lot* of mone
Re:Scalability and Twelve Step TrustABLE IT (Score:2)
it's not an excuse to miss research on what the system could be hit with.
Re:Scalability and Twelve Step TrustABLE IT (Score:2)
Wow, I didn't know that 3270 emulators were even programmable, and surely wouldn't try to base an airline reservation system on them. Seems far better to use something like a mainframe than a grid of terminal emulators, although there must be a few distributed mips there...
Scalability on demand and third party servers (Score:2)
If you choose a standardize
This is getting a little to common for them. (Score:4, Interesting)
Re:This is getting a little to common for them. (Score:2)
From old information... (Score:5, Informative)
This article [20minutesfromhome.com] outlines how this joint venture re-vamped Delta's IT systems (again remember, this is 1995):
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 [airlinefinancial.com], is described as
Wipro handles some of Delta's inbound reservation calls in India and the Phillipines. [wipro.com]
In conclusion, it would appear that either Tata's AFS arm or Wipro do the IT for Delta airlines.
Re:From old information... (Score:2)
But management saved 13.7% by hiring H1-Visas (Score:2, Interesting)
Re:It's a tragedy when... (Score:2)
this story as an evidence.
though seriously, there's quite a lot of companies out there that instead of hiring incompetent people could be better off buying the services from outside. outsourcing doesn't necessarely mean it's crap, there's a lot of domestic in-house crap and idiots everywhere.
Crew assigment is a hard problem (Score:5, Informative)
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 (Score:2)
Re:Crew assigment is a hard problem (Score:2)
Then it's a matter of feeding the data at a rate so you don't backlog faster than the amount of data you get in.
If you ar
Re:Crew assigment is a hard problem (Score:3)
Re:Crew assigment is a hard problem (Score:5, Interesting)
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.
Can anyone say... (Score:3, Funny)
30,000? (Score:5, Funny)
Re:30,000? (Score:5, Funny)
That is not a bug but an accurate model of reality. When you strand 32,768 passengers, they will turn negative.
I don't know about their internal system... (Score:3, Interesting)
So don't assume that the internal system was Windows just yet. Then again, don't assume that it wasn't.
Re:I don't know about their internal system... (Score:2)
whole story? (Score:5, Informative)
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/ [syslog.org]
Re:whole story? (Score:5, Interesting)
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.
Re:whole story? (Score:3, Informative)
This summer, I was flying from Paris to Ft. Lauderdale via Philadelphia on USAir. The Paris->Philadelphia leg was handled by the same plane that does USAir's Philadelphia->Paris flight that same day. The incoming flight was about four hours late, so of course our outgoing flight was also four hours late. Sucks, but what can you do.
So we get into Philadelphia at about 9PM instead of 4:30PM and everybody rushes to get
Re:whole story? (Score:3, Informative)
Okay troll, I'll bite. Maybe he had a limited amount of time off. Maybe that was the most convenient time to fly. Whatever. It doesn't matter.
He shouldn't have to plan for weather, high traffic, and/or computer screwups. That is the airlines JOB. You know, the people who took the money and agreed to get him from point A to point B. Bad weather in the winter? From the massive effects it has on th
Not surprising, coming from Comair (Score:5, Interesting)
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.
I'm surprised (Score:2, Interesting)
Re:I'm surprised (Score:4, Insightful)
What else do they have to do? They've got this huge ass budget, all those people watching a lot of honest citizens. It was 10 years between the first attempt on the world trade center and the second. We've built and paid for this entire monster agency for an event that might be 10 or 15 years away. What are they going to do in the meantime? Grope women at the airport. They have to do something to justify their existence, Otherwise we'd have admit we over-reacted to 9-11.
It's obvious what happened (Score:2, Funny)
No manual process? (Score:2)
Re:No manual process? (Score:2, Insightful)
seen it before (Score:2)
Sounds like Diebold may have been contracted for the job.
I'd like to know (Score:3, Interesting)
This is a worst case scenario for a system of that nature because of so many dependent calculations and calls to other systems. It takes more than just having a plane and a crew...which is a lot of work all by itself. It has to have a gate and connecting flights. Then multiply all that by 30,000 people, roughly 120 plane loads, and complicate it by some airports being closed. I bet you could actually watch the lights get dimmer in the server room. Still when you know the potential peak demand you have reserve capacity. Slow is okay, stop is unacceptable.
Bailout (Score:2)
Southwest refuses to drink the Kool-aid (Score:5, Interesting)
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 (Score:3, Interesting)
Re:Southwest refuses to drink the Kool-aid (Score:4, Insightful)
The hub-spoke system is easier to manage, and can be profitable if the airlines relize that they aren't unlimited resources, and decentralize the hubs on a limited basis.
Anyways Southwest doesn't drink anyone's koolaid, they run all their own in house designed systems (I am not sure they are even on Sabre anymore), including web apps. It's an intresting concept, but it probably causes their IT managers to pull their hair out.
Re:Southwest refuses to drink the Kool-aid (Score:4, Informative)
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.response from an AA employee (Score:3, Interesting)
---
"ugh... I worked 9pm-1am yesterday (xmas day). I spent the first two
hours of my shift calling people to tell them their flight was
cancelled and reschedule them. Most of them were taking flights out to
Miami and the Caribbean to spend New Years Eve partying on the beach.
Honestly, I had little pity telling them they were going to miss out on
one day of tanning especially since they seem to 'blame' the weather on
us.
"One hour into my shift our reference system went down. No IT people
were willing to come in and fix it. I had the system up for booking
flights and making reservations, but I could not look up any of our
rules and regulations. Ah well, enjoy your xmas off IT guys!! Enjoy
the weather in Cabo San Lucas!! Cheers!!
"Fortunately, we have a backup of all our html files saved as text
files. However each text file can only hold serval hundred text
characters. So, when I want to look up our baggage policies the normal
html file is called BAG INFO. In the backup system BAG INFO is
separated into 10 or 20 text files and I have to 'page' through them by
typing BAG INFO P2, BAG INFO P3, BAG INFO P4. The text files are not
indexed and are not searchable. It took me 10 minutes to find and
advise someone how big a bag they can take to Puerto Rico.
"After I started taking incoming calls again, there were people calling
in on Christmas day to book their trips for Spring Break. There were
over 100 calls on hold to talk to us, and there were people sitting on
hold for half an hour to ask me how much it would cost to book a trip
to Fort Lauderdale in March. Couldn't that wait until the day after
Christmas?
"Yes, the airline industry does not prepare for emergencies as well as
it could for the holidays when people want to travel in record numbers.
However, I think the general public could try to have their own backup
plans in place as well and realize that the travel industry in general
does not have the equipment or the staff to handle everyone in the
country wanting to travel all at once in one week. Do people stock
their refrigerators year round with enough food to feed everyone in
their families at one meal like they do at Christmas?
"Even though we try to accommodate everyone as best as we can on the
holidays, we want to to have a holiday just as bad as the rest of
everyone else. Working in the travel industry should not indenture us
to be your slaves over holidays. The public needs to have a little bit
of compassion and realize how much we give up in our own personal lives
just to help you get where you are going. Frankly, the way most people
treat me on the phones I don't think they deserve our help and
compassion. And don't call on Christmas day to book flights in March.
That phone call is making someone work on a day they shouldn't have to.
"anyways.... heh..... guess i had a bad night at work last night, huh
"MERRY XMAS!"
Re:The system runs Linux (Score:2)
Re:The system runs Linux (Score:2)
Re:The system runs Linux (Score:2)
Knowingn nothing else, I'd guess they overflowed a key database partition. A lot of old programmers very foolishly over-partition available disk, trying to outguess the OS about what partition will need how much space and instead of protecting themselves from disast
Re:Travel tip (Score:5, Informative)
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.
Re:Travel tip (Score:2)
Re:Slashdot this (Score:2)
Read the code, Luke (episode II) (Score:5, Funny)
{friggin' slash - When I say plain old text, I mean plain old text!}
Re:Simple Solution (Score:4, Insightful)
p