Flight Chaos! Britain Is Grounded!

The undeniable truth · Aug 30, 2023

Ilkley said: ↑

I do love to hear from people who know what they're talking about.
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Well you have to assume they know what they’re talking about…..

sydney_horn · Aug 30, 2023

StuBoy said: ↑

Back home now and we got away with it for sure today. Went through the airport onto our flight and back home as if the storm hadn’t happened in Majorca on Sunday and the AT failure hadn’t happened yesterday. So thankfully, for the kids especially, the travelling was fine. I must say, although things aren’t great, as usual the media spin is making it out to be travel Armageddon. Of course that’s just my experience from Palma in Majorca today.
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I flew out from Gatwick yesterday. It was no busier than usual imho. Flight took off on schedule.

The media love a disaster drama so definitely a lot of negative spin by them.

Malteser2 · Aug 30, 2023

The undeniable truth said: ↑

Well you have to assume they know what they’re talking about…..
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I admit I didn’t understand any of Skylab’s post. It all seemed to be written in code to me.

Heidar · Aug 30, 2023

SkylaRose said: ↑
No, C++ is a programming language as is Ada. They are relatively the same age and size but Ada is a much safer language. C++ has big problems due to it's handling of memory, almost all of it is done with raw pointers that are coded by hand. While not a problem in the hands of an experienced developer, the slightest slip up could spell the sort of disaster we have seen.
Code:
class Example
{
public:
    Example();
    ~Example();

protected:
    unsigned int*       sum;
};
Usage in program without proper care:
Code:
if (sum == 10)
{
 // do something
}
else
{
    try  // this will always fail
    {
        restart();
    }
    catch(unhandled Exception ex)
    {
        // do something with the exception
    }
}
In a nutshell, the statement sum == 10 will fail because the computer is trying to access a possible non-positive number by it's value. Because 'sum' is declared within the sample class as a pointer to the address of sum, it will not return any result that the can be computed. Pointers need to be "de-referenced" when they are used. You could get the memory address of sum with:
Code:
int sum = &sum;
To correct the above example, sum needs to computed with the memory address that sun is pointing to. Hence:
Code:
if (*sum == 10)
Is valid because sum is not being directly accessed, the memory location of where the computer has the value of sum stored is.

Now in Ada, pointers do exist, but they are used very sparingly. Instead of accessing the data through a manual call to the address by de-reference, it is already known to the compiler at compilation due to the variable being declared having the access to the value granted through the language.
Code:
type Example is tagged record
Sum : Natural;
end record;
So now I have created a single record (package) that holds single variable sum, which is declared to be Natural (it cannot be false positive or negative). It's also "tagged" so it's access is restricted.
Code:
type My_Example is access Example;
This is the same as the C++ statement, but the de-reference is not required. My_Example already has full access to the memory address of Sum through the tagged record type.

This is a very small example of how safety differs between the two languages, but the main point is, if the error within the ATC was a memory leak this the main cause of it. Just missing out an single '*' when executing the binary will send the program into meltdown, because this sort of error, as far as the C++ standard is concerned, is 100% correct.
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Oi, no professionals

WillisWasTheWorst · Aug 30, 2023

Well, Minister, the usual thing to do in these circumstances is to blame the French.

Since63 · Aug 30, 2023

SkylaRose said: ↑
No, C++ is a programming language as is Ada. They are relatively the same age and size but Ada is a much safer language. C++ has big problems due to it's handling of memory, almost all of it is done with raw pointers that are coded by hand. While not a problem in the hands of an experienced developer, the slightest slip up could spell the sort of disaster we have seen.
Code:
class Example
{
public:
    Example();
    ~Example();

protected:
    unsigned int*       sum;
};
Usage in program without proper care:
Code:
if (sum == 10)
{
 // do something
}
else
{
    try  // this will always fail
    {
        restart();
    }
    catch(unhandled Exception ex)
    {
        // do something with the exception
    }
}
In a nutshell, the statement sum == 10 will fail because the computer is trying to access a possible non-positive number by it's value. Because 'sum' is declared within the sample class as a pointer to the address of sum, it will not return any result that the can be computed. Pointers need to be "de-referenced" when they are used. You could get the memory address of sum with:
Code:
int sum = &sum;
To correct the above example, sum needs to computed with the memory address that sun is pointing to. Hence:
Code:
if (*sum == 10)
Is valid because sum is not being directly accessed, the memory location of where the computer has the value of sum stored is.

Now in Ada, pointers do exist, but they are used very sparingly. Instead of accessing the data through a manual call to the address by de-reference, it is already known to the compiler at compilation due to the variable being declared having the access to the value granted through the language.
Code:
type Example is tagged record
Sum : Natural;
end record;
So now I have created a single record (package) that holds single variable sum, which is declared to be Natural (it cannot be false positive or negative). It's also "tagged" so it's access is restricted.
Code:
type My_Example is access Example;
This is the same as the C++ statement, but the de-reference is not required. My_Example already has full access to the memory address of Sum through the tagged record type.

This is a very small example of how safety differs between the two languages, but the main point is, if the error within the ATC was a memory leak this the main cause of it. Just missing out an single '*' when executing the binary will send the program into meltdown, because this sort of error, as far as the C++ standard is concerned, is 100% correct.
Click to expand...
Thanks for the comprehensive reply, Skyla. I’ve just plucked up the courage to admit my juxtaposition of ‘E-‘ and ‘C++’ was meant to be a jokey allusion to exam grading….
Reading through your post, I have to say I’m not disappointed that IT studies were not available when I was at school, but I’m glad someone enjoys doing it!

The undeniable truth · Aug 30, 2023

Since63 said: ↑

Thanks for the comprehensive reply, Skyla. I’ve just plucked up the courage to admit my juxtaposition of ‘E-‘ and ‘C++’ was meant to be a jokey allusion to exam grading….
Reading through your post, I have to say I’m not disappointed that IT studies were not available when I was at school, but I’m glad someone enjoys doing it!
Click to expand...

Did they even have computers when you were at school, let alone IT studies ?

Since63 · Aug 30, 2023

The undeniable truth said: ↑

Did they even have computers when you were at school, let alone IT studies ?
Click to expand...

Ha-ha, funny. When I went into the lower 6th it was possible to do a term of ‘an introduction to computer studies’ but it was limited to about 10 people per term and I didn’t bother trying. The room that housed the computer was about twice the size of the classroom in which the lessons were taught!

hornmeister · Aug 30, 2023

Since63 said: ↑

Ha-ha, funny. When I went into the lower 6th it was possible to do a term of ‘an introduction to computer studies’ but it was limited to about 10 people per term and I didn’t bother trying. The room that housed the computer was about twice the size of the classroom in which the lessons were taught!
Click to expand...

I bet you also didn't fancy carry around suitcases full of punched cards either?

Since63 · Aug 30, 2023

hornmeister said: ↑

I bet you also didn't fancy carry around suitcases full of punched cards either?
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Wheelbarrows back then, don’t you know?

Teide1 · Aug 30, 2023

hornmeister said: ↑

I bet you also didn't fancy carry around suitcases full of punched cards either?
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Don’t forget the paper tape!

Keighley · Aug 30, 2023

What’s a computer?

(Eat yourself fitter).

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Flight Chaos! Britain Is Grounded!

The undeniable truth First Team Captain

sydney_horn Squad Player

Malteser2 Reservist

Heidar Squad Player

WillisWasTheWorst Its making less grammar mistake's thats important

Since63 Squad Player

The undeniable truth First Team Captain

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hornmeister Tired

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