F-22 Avionics Require Inflight Reboot

An anonymous reader writes "The Atlanta Journal & Constitution is fronting a lengthy piece on the USAF's new F-22 and its upcoming shootout with the existing fleet of F-15's & 16's. One line in the article really jumped out at me: 'When avionics problems crop up now, pilots must restart the entire system as if rebooting a personal computer.' I did some googling, and this is about as much as I could find: The hardware backbone for the system is the Hughes Common Integrated Processor, which, in turn, appears to be built around the Intel i960 CPU. I couldn't find a name for the operating system, but it appears to be written in about one and a half million lines of Ada code; more on the Ada hardware integration and Ada i960 compilers is here. Any Slashdotters working on this project? If so, why do you need the inflight reboot? PS: Gamers will be interested to learn that nVidia's Quadro2 Go GPU and Wind River's VxWorks Operating System are melded in the F-22's Multi-Function Display."

Comments

How I solved this for a heads up display - 15 ya

[jerryasher]

Sine, cosine? Assuming you have a line draw routine and a raster display, none of that is needed.

About fifteen years ago for a prototype heads up display I had the same exact problem: draw the tick marks for a compass rose with no memory and no time. There was no scaling of the circle, only rotation about a fixed center.

After some though, what I did was to store in a table the tickmark endpoints for 45 degrees of arc (I recall it being 22.5 and not 90 degrees) for all the displayable rotations of that arc. Then at runtime, my compass rose routine would exploit the symmetry of the situation to determine the endpoints of all the other displayable tickmarks.

It used very little memory since at any point in time we only displayed tick marks at 5 degree intervals. Therefore 45 degrees of those would be 9 tick marks, or 18 ints (two ints per tickmark). At 5 degree intervals with a resolution of 1 degree, you only need a table of 5 x those 18 ints, or 90 ints all told.

I always loved the 3am epiphany!

Re:There Is Something Rotten in Software Engineeri

[Black Parrot]

> Software functionality should not be fundamentally different from hardware functionality.

Am I to understand that you are saying that software, like hardware, should only fail when it fails?

Granted, we have a software reliability crisis on our hands. But hardware isn't generally fault-free either. I've had a lot more Zip drives die on me than I've had kernel panics. And arguably a kernel is much more complex than the design of a removable disk drive.

> An algorithmic system is temporally inconsistent and unstable by nature.

That's an absurd claim. It's possible to prove correct behavior for algorithmic systems. Time is explicitly accounted for in most such proofs.

The biggest engineering difference between software and hardware is that people find software errors acceptable, or even normal, whereas they have never reconciled themselves to, say, collapsing bridges or wings falling off of airplanes. When that attitude changes we'll start seeing software that rivals hardware in reliability, not before. Most of the engineering concepts required for producing good software have been around for quite a while.