Question for Comair folks...

[smellthejeta]

OK, one more try. By the way, the computer language used makes no diference at all. Doesn't matter if it's FORTRAN, C, Basic, or assembly language. The issue is whether the programmer wrote the program to correctly handle arithmetic overflow errors.

Computers use binary arithmetic. All digits are 1s and 0s. An integer number can be signed or unsigned (unsigned means positive numbers only, signed numbers can be positive or negative).

Computers process data in chunks of bits.
A byte is 8 bits which can represent 0 to 256 (unsigned) or -127 to 127 (signed).
A word is 16 bits which can represent 0 to 65536 (unsigned) or -32767 to 32767 (signed)
A longword is 32 bits which can represent 0 to 4294967295 (unsigned) or -2147483647 to 2147483647 (signed).

So it looks like the program Comair was using was tracking change events with a 16 bit signed integer value. The number of changes hit the limit (32767) and then went 1 over. Whenever that happens, the positive number now overflows to a negative number and the computer throws a numeric overflow exception. If the programmer who wrote the program never anticipated that an overflow would happen, he probably did not code for the event and the program crashed (apparently without saving any data).

One of the things that strikes me as odd is why the programmer would have chosen a signed int when a negative number is probably never used in that variable.

 

[LarryinTN]

Mebbe in the freightdog world..... 1 in 7 for sked service means at base, free of duty..

Read the regs. 24 in 7 can be anywhere as long as you're off duty. Any additional restriction is from your contract.

The "freightdog world" has it's advantages. I'm currently in the middle of 15 scheduled days off. No vacation. No sick leave. Just 15 consecutive scheduled days off. Additionally, in 2004 I fly less than 400 hours block time and was paid for 929.9.

 

[Snoopy58]

One of the things that strikes me as odd is why the programmer would have chosen a signed int when a negative number is probably never used in that variable.

The programming language may not have offered the choice between a signed & an unsigned integer. Back in the days of BASIC, you had choices like integer, real, string, and then arrays of various sizes. The programmer can deal with all the errors to HIS code that he can think of, but if the code out of the complier / interpreter has a problem (overflow, etc), that's beyond what the coder has much control over.

 

[DaveJ]

One of the things that strikes me as odd is why the programmer would have chosen a signed int when a negative number is probably never used in that variable.

I believe that signed integers are the default for FORTRAN.

Back in the 80s, I was a contract programmer for Delta at their jet base for a number of years. Most of the systems I dealt with were written in FORTRAN on an IBM mainframe. Some of the things I was working on were more modern, using C, X-Windows and relational databases.

I was the project leader for a scheduling system called the Aircraft Routing System (ARC). ARC took the Aircraft Control Time Log (ACTL) report of maintenance coming due on each aircraft each day, massaged the ACTL against the flight schedule from marketing and calculated the flight schedules for each aircraft. The trick was to make sure each a/c with maintence coming up would overnight at a maintenance station that could actually perform the maintenance without exceeding the hour, cycle, or day limit on the maintenance.

 

[FlyComAirJets]

Imagine old Admiral Grace Hopper

The programmer who wrote all this mess has probably died of extreme old age.

 

[Anaconda]

The article seems to place blame on Delta because of the low IT budget it has allocated.

that was the first article i've seen that actually pins some of the blame on delta. in the past few days it seems dal has wanted to deflect all of the responsibility on comair.

 

[Slim]

Several days ago, on the FNC web site, an article about Comair and USAirways lumped the problems together...computer failures, weather and illegal job actions. The way the article was written, I could see this slant coming and it happened.

Yesterday, Rush Limbaugh's guest host, Roger Hedgecock (?), was taking exactly that approach. One of his callers, a Comair F/A tried to set him straight. He didn't realize there was no job action situation at Comair, but then took a different track. He said Comair was created by DAL to lower their costs. He expressed several other inaccuracies. One was that Comair, like USAirways, is on the verge of bankruptcy.

I heard this slant, again, on several other radio talk shows today. I certainly hope corporate communications is going to try to set some things straight (but am not holding my breath!).

Has anyone else noticed this?

 

[surplus1]

If you listen to the likes of Rush Limbaugh you deserve whatever you hear.

 

[I.P. Freley]

I guess we should all listen to Al Franken instead. He's ALWAYS right.

 

[Slim]

I listen to, and read, a variety of news sources. That includes ALPA. That way, I can get my hands on as much information as possible, then get a feel for what is really happening. Rush Limbaugh has never been, and never will be, my only source of information.

Rush, FNC and others in the national media are falling into the trap I described in my earlier post. The local CVG media outlets are not buying into the labor actions excuse. Other outlets, unfortunately, are doing so.

Local TV stations are doing a better job reporting the facts. Unfortunately, when their national network (ABC, CBS, NBC) news comes on, there's conflicting information over the same story.

The Enquirer quoted a former DL F/A who clearly had no knowledge of the facts. Her assertions went unchallenged.

I was a communications major in college. What I learned then is not being practiced today and hasn't been for the last 15-20 years. Too many reporters don't verify their facts. Mainstream media outlets wonder why their credibility continues to diminish.

Fly safe!

 

[surplus1]

Too many reporters don't verify their facts.

I agree with that. Of course it is also true that Rush Limbaugh is not a "reporter". He's nothing more than a propagandist, therefore he has no need to verify or be concerned about "facts" and seldom broadcasts any.

This man is a blowhard with an agenda. "Facts" have never interfered with his opinions.

 

[737 Pylt]

This man is a blowhard with an agenda. "Facts" have never interfered with his opinions.

You mean kind of like yourself, Huh surplus??
737

 

[Tim47SIP]

You mean kind of like yourself, Huh surplus??
737

Darn! You beat me to it. His posts over the last few months have unequovocally proved one thing. He IS the king of spin. What a tool!

 

[General Lee]

Surplus1 has some good points, well, that is if you can find them in his 15 page diatribes explaining how Dalpa is out to get him.


Bye Bye--General Lee

 

[surplus1]

Thank you gentlemen. Now I would like the three gentlemen (737Pylt, Tim47SIP and the General) to all get together, hug each other intensly and sing Kumbaya. When they're finished there will be photo ops and refreshments in the lounge.

Everyone smile politely, applaud generously and feign interest.