In-Flight Reboot? 594
Posted
by
michael
from the no-problems-until-you-have-to-fsck dept.
from the no-problems-until-you-have-to-fsck dept.
steelem writes "The Washington Post is running a story about how the F-22 Raptor's software requires in-flight reboots. Apparently the 2 million line software project is 93% done. Knowing most projects I've been on, it'll stay that way for another few years."
Found more on Google. (Score:3, Informative)
The first hit on Google was this [slashdot.org] interesting take on the story.
Re:Why reboot systems at all? (Score:4, Informative)
There are several redundant systems. Let's say for example that your FLCC has 3 identical systems. If one fails, the other two take over until the watchdog timer kicks in and restarts the third (in the case of a software fault).
Anything that is rated for piloted flight is this way, especially fly-by-wire systems or other mission critical components.
This claim is not surprising at all, since it happens all the time.
Humorous (Score:2, Informative)
Sounds sort of scary to me the such a critical component needs to be rebooted at all, boy, I'm glad I'm not a test-pilot.
Re:LinuxBIOS in flight computers (Score:5, Informative)
AFAIK, civilian flight systems are three times redundant. Written by three different isolated teams in three different programming paradigms, from three different cultures to avoid similar faults due to "contamination" by other teams, or simlar faults due to similar paradigms.
(Airbus 340 (3M LOC), Boeing 777 are said to have employed such techniques)
And IRC, they don't fly with at least two redundant fully functional systems.
It makes me wonder why the military has less stringent requirements.
Re:Why reboot systems at all? (Score:4, Informative)
Re:LinuxBIOS in flight computers (Score:5, Informative)
Very unstable yet very maneuverable.
Re:Ejection Seat (Score:2, Informative)
http://www.martin-baker.co.uk/
Propulsion System - an adaptive propulsion system is provided that performs to best suite the prevailing ejection conditions e.g. pilot boarding mass, ejection speed, aircraft attitude. This comprises the proven Mk16-type, self regulating ejection catapult design, and a new switchable under seat rocket motor that allows one of 4 modes/thrust levels to be selected, under the control of the seat microprocessor sequencer.
In F-22 they use the ACES II.
The seat picks the mode of ejection based on conditions, speed, G, etc. The seat automaticly picts the mode of parachute deployment. In a typical ejection the following happens.
Rocket-Catapult Fires
Drogue Deploys
STAPAC Ignites
Parachute Deploys
Drogue Releases from seat
Seat Releases from Crewman
Parachute Inflates
Survival Kit Deploys
This stuff happens automaticly and more stages can be added for things like firing pyros to destroy black boxes, restraining limbs during the ejection, firing transponders, auto deploying life vests and so forth.
Re:Why is this a big deal? (Score:5, Informative)
The sensor fusion software's task is to combine the data from all of the various sources (radar, RWR, multiple datalinks etc.) and redistribute it among the systems that could benefit from it. For example, a target detected by radar would show also up on the Horizontal Situational Display, and would also be re-transmitted via datalink to JSTARS and/or AWACS and any other datalink-capable aircraft. In addition, contact information can correlated for maximum accuracy. A target's radar emissions could be detected by the Radar Warning Receiver, and that information could then be used by the radar for Non Cooperative Target Recognition allowing the radar to display the type of target (though NCTR in the F/A-22 reportedly works differently from this). All of the numerous sensors on the F/A-22 have their resources and products pooled together, allowing for extremely effective target detection, tracking and ID. Sensor fusion is an incredible development in avionics and is one of the foundations of 5th generation fighter aircraft technology.
Re:Avionic stability? (Score:5, Informative)
The APG-77 has a terrain following mode. And the widely spread weak emissions from it are much harder to detect than those from a conventional radar.
The Martin-Baker ACES II ejection seat can save a pilot's life from zero feet of altitude (that's why it's called a "zero-zero" ejection seat- effective down to zero altitude and zero speed)
More details from Code One magainze (Score:2, Informative)
http://www.codeonemagazine.com/archives/2003/ar
Re:What does reboot even mean in this context? (Score:3, Informative)
Re:Hah (Score:3, Informative)
Yeah, I know, if I have to explain a joke, it's not funny. Oh well...
The apollo computers (Score:1, Informative)
THey ran a program. If the program crashed, you'd just restart the program. Its that easy. Think of Apple II or TRS-80, and you have a computer with 100 times the ability.
These things were a lot simpler than you're thinking.
F-16 IFF (Score:1, Informative)
Re:Su-30 series or Quality/Quantity (Score:3, Informative)
Um...bullshit.
The F-15 had to perform the cobra in acceptance testing. It's covered in 4.2 of Mil Std 1787. There are other aircraft that can also perform the maneuver. The cobra is nothing more than a pitch overshoot in response to a "stick snatch." It's part of routine acceptance testing, although it's usually performed at medium to high altitudes.
Some aircraft perform it easier than others. For still other aircraft, the manuever gets easier if you set the plane up for it, as they do with Su-27s at airshows (you've got to manipulate the cg and override the FCS).
Many aircraft simply aren't cleared to perform the maneuver, and it's not covered in pilot training, even with the Su-27. The reason for this is that it's a very showy maneuver that has no use in the practical or tactical realms. That "Goose, I'm gonna hit the brakes and he'll fly right by" is bullshit Hollywood crap; in a real dogfight, the guy behind you might overshoot when you dump that much speed that fast, but all that means if that now you're meat on a stick for his wingman.
The Mig-25 was already obsolete then in terms of technology but the sheer speed of the plane (Mach 2.8+) is unmatched by any other fighter.
Note that shortly after reaching that top speed, it needs new engines.
Quantum Gate (Score:3, Informative)
The "sequel that never happened" happened around 1995 and was called The Vortex: Quantum Gate II [adventurecollective.com], it continued your adventures on the other side of the quantum gate. They actually released a soundtrack [amazon.com] to this one.
WRONG (Score:2, Informative)
Besides, I'd love to see three sets of hardware (all totally different) run the *same* software. Without any modification.
Re:What's it written in? (Score:2, Informative)
Re:Su-30 series or Quality/Quantity (Score:4, Informative)
The Mig-25 borders on a desparation weapon. It was designed specifically to counter high altitude bombers and spy planes that the United States routinely flew over Soviet airspace. In that it failed. It's fairly clear today that a Mig-25 could not sustain the speed or attain the altitude necessary to attack an SR-71.
The Soviet Union pawned off various models of the Mig-25 to the third world. Iraq had probably 15 Mig-25s at the start of the Gulf War (the first), of which perhaps 7 were operational.
The shootdown happened because the Mig was misidentified multiple times as it flew past an American strike package. Had it been identified, it would have been killed. The shootdown was more the result of tactics than technology. That Mig pilot was both brave and lucky.
The Mig was not moving at Mach 2.8. A Mig-25 can only do this at high altitude (70K+) and only for a short time. The shootdown happened between 25-30K, where the F-18's were operating. Flying at almost Mach 3 destroys the engines of a Mig-25. This isn't a problem if you're goal is to hit one high-value, high-altitude target and glide back to base. It does matter if you intend to engage in sustained warfare.
In 1976, a Soviet defector landed a 1976-built Mig-25 in Japan. A few interesting things [wvi.com] were learned; with a full load of weapons and fuel a Mig-25 can handle only slightly more than 2Gs of force. At it's best it can handle about 5gs. This is no dog fighter. An F-4 can do better, much less any modern aircraft.
Re:Su-30 series or Quality/Quantity (Score:3, Informative)
For the record, I misquoted the story. Here's a link [lucia.it].
I quote: "Gulf War Experience -
Did you know that a MiG-25PD recorded the only Iraqi air-to-air kill of the Gulf War? It dropped an F-18C on the first night of the war--then went on to fire another missile at an A-6 and buzz an A-7, all while avoiding escorting F-14s and F-15s.
An isolated incident? How about the single Iraqi Foxbat-E that eluded eight sweeping F-15s then tangled with two EF-111As, firing three missiles at the Ravens and chasing them off station. Unfortunately, the Ravens were supporting an F-15E strike, and the EF-111's retreat led to the loss of one of the Strike Eagles to a SAM. Oh BTW, the Foxbat easily avoided interception and returned safely to base.
There's more. When F-15 pilots were fighting for the chance to fly sweeps east of Baghdad late in the war, itching for a chance to get a shot at an Iraqi running for Iran, they weren't expecting the fight that a pair of Foxbats put up. Two Foxbats approached a pair of F-15s, fired missiles before the Eagles could get off shots (the missiles were evaded by the Eagles), then outran those two Eagles, four Sparrows and two Sidewinders fired back at them. Two more Eagles maneuvered to cut the Foxbat's off from their base (four more Eagles tried, but were unable to effect an intercept), and four more Sparrows were expended in vain trying to drop the Foxbats.
The Iraqis had a total of twelve MiG-25PDs at the beginning of the war, of which maybe half were operational at any given time. Imagine what trouble they would have caused if there had been more. The Foxbats, when well flown, proved capable of engaging allied fighters and avoiding them at will. Only the limitations of their weapons proved a problem."
Re:The apollo computers (Score:1, Informative)
Re:LinuxBIOS in flight computers (Score:2, Informative)
Not necessarily true. To certify software systems using the currently accepted civilian standards for software development (DO-178B), you need to show through analysis that the failure rate of the entire system is below some threshold. One way to attain that threshold is to use multiple, redundant systems that have a higher-than-threshold failure rate, such that the combined failure rate is below the threshold. There is no requirement to use redundancy; it just happens to be an effective way to meet the failure threshold.
I have developed avionics software for business jets and I can tell you that the system on which I worked was designed to be only two-times redundant, and it was redudant with another instance of itself, not a wholly independent system. That level of redundancy was sufficient to meet the required failure threshold.
Re:What does reboot even mean in this context? (Score:1, Informative)
Re: LinuxBIOS in flight computers (Score:3, Informative)
> The language used for all of this is ADA, which is one devious language to program in.
Actually, I find Ada [sic] quite elegant to program in.
> Everything requires exception handling, and every exception needs to be handled.
Actually exception handlers are optional. But in avionics you probably do want to handle exceptions, regardless of which language you're using.
> The 2 million lines of code is surprising, not because it seems like a lot, but because it seems like so little.
Ada is somewhat verbose because it uses "begin" and "end" instead of "{" and "}", and a few other things along that line, but it's absurd to pass judgement on the size of a program without the slightest idea how many function points it implements.
In my experience, the more familiar I become with Ada the more lean and elegant my programs are. As with virtually every other programming language, you can set up abstractions and program at "a higher level" than Joe Noobie would do. Possibly the F-22 avionics were programmed by noobies or idiots, but somehow I doubt it.
Re:LinuxBIOS in flight computers (Score:5, Informative)
Correct (Score:2, Informative)
Re:Recorded radio chatter of the future (Score:3, Informative)