3 ms·

What is the other 1%? (I was only able to glance through pieces of the article for now)

ajb 12y ago
Probably the coffee machine. Although given the effort required to write safety critical code, I wouldn't be surprised if the coffee machine had more lines of code than the rest of the airplane.
- twistedpair 12y ago
  The galley is a main source of in flight fires. I'd expect such systems to be classified as critical to flight safety. Obviously not as much as the auto pilot, but it is still a system that could bring the plane down if an oven or cofee pot shorts. IFE, on the other hand, is not.
- userbinator 12y ago
  I wouldn't be surprised if the coffee machine didn't have a single microcontroller in it, but a simple old-fashioned analogue controller. The prevailing attitude in safety-critical systems is "if it works (and has been certified with much $$$), leave it alone".
Narkov 12y ago
Presumably PHP.
raverbashing 12y ago
If I had to bet it would be the non-safety systems, like lighting Or just their website and intranet maybe?
ghshephard 12y ago
Given how reliably the video system fails on the 777, I'm going with the In Flight entertainment system.
- saryant 12y ago
  Boeing doesn't manufacture those. AFAIK Panasonic is the leading vendor today.
WildUtah 12y ago
The hardware access routines, real time operating system, and bottom level I/O can't be written in ADA. CPUs accept only machine code, so those programs have to be written at least partly in machine code. Likewise the compiler has to generate CPU instructions,the opcodes and operands of which are embedded in the code generator as binary data. That is code that isn't in ADA either.
- amock 12y ago
  Ada get compiled to machine code, so of course it can run directly on the CPU. There's also no reason it can't be used to write a compiler and there's probably several Ada compilers written in Ada. I'm not sure what you mean about binary data having to be embedded in the code generator; you can easily generate arbitrary binary data from almost any language.
- axman6 12y ago
  > The hardware access routines, real time operating system, and bottom level I/O can't be written in ADA. I disagree, Ada has fantastic tools for writing these sorts of code; you can precisely define data types down to the bit level and their precise locations and endianess in memory. Have a look at pages 50-68 of [1] to see these in action. you don't have to know Ada to be able to see what's being defined, and that's it exactly matches the specification of the memory mapped IO registers. Some reference c code is given, but there is no guarantee that the compiler will do what you want; the Ada language does guarantee it. [1] http://cs.anu.edu.au/student/comp4330/Lectures/RTES-03%20Interfaces.01.pdf http://cs.anu.edu.au/student/comp4330/Lectures/RTES-03%20Int...
- pjmlp 12y ago
  It seems you never programmed in Ada...

ajb 12y ago

Probably the coffee machine. Although given the effort required to write safety critical code, I wouldn't be surprised if the coffee machine had more lines of code than the rest of the airplane.

twistedpair 12y ago
The galley is a main source of in flight fires. I'd expect such systems to be classified as critical to flight safety. Obviously not as much as the auto pilot, but it is still a system that could bring the plane down if an oven or cofee pot shorts. IFE, on the other hand, is not.
userbinator 12y ago
I wouldn't be surprised if the coffee machine didn't have a single microcontroller in it, but a simple old-fashioned analogue controller. The prevailing attitude in safety-critical systems is "if it works (and has been certified with much $$$), leave it alone".

Narkov 12y ago

Presumably PHP.

raverbashing 12y ago

If I had to bet it would be the non-safety systems, like lighting Or just their website and intranet maybe?

ghshephard 12y ago

Given how reliably the video system fails on the 777, I'm going with the In Flight entertainment system.

saryant 12y ago
Boeing doesn't manufacture those. AFAIK Panasonic is the leading vendor today.

WildUtah 12y ago

The hardware access routines, real time operating system, and bottom level I/O can't be written in ADA. CPUs accept only machine code, so those programs have to be written at least partly in machine code. Likewise the compiler has to generate CPU instructions,the opcodes and operands of which are embedded in the code generator as binary data. That is code that isn't in ADA either.

amock 12y ago
Ada get compiled to machine code, so of course it can run directly on the CPU. There's also no reason it can't be used to write a compiler and there's probably several Ada compilers written in Ada. I'm not sure what you mean about binary data having to be embedded in the code generator; you can easily generate arbitrary binary data from almost any language.
axman6 12y ago
> The hardware access routines, real time operating system, and bottom level I/O can't be written in ADA. I disagree, Ada has fantastic tools for writing these sorts of code; you can precisely define data types down to the bit level and their precise locations and endianess in memory. Have a look at pages 50-68 of [1] to see these in action. you don't have to know Ada to be able to see what's being defined, and that's it exactly matches the specification of the memory mapped IO registers. Some reference c code is given, but there is no guarantee that the compiler will do what you want; the Ada language does guarantee it. [1] http://cs.anu.edu.au/student/comp4330/Lectures/RTES-03%20Interfaces.01.pdf http://cs.anu.edu.au/student/comp4330/Lectures/RTES-03%20Int...
pjmlp 12y ago
It seems you never programmed in Ada...