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In this video I would like
to talk a bit about CPU architecture.

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So the CPU architecture defines how
instructions are executed on the cpu.

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And it's still the case that if
you have a program that is compiled

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for ARM, it won't work on
Intel CPUs and the other way around.

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Why is that? Well, that's because
Intel CPUs use the complex instruction

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set computing CISC ARM CPUs use
reduced instruction set computing or RISC.

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And that has been a main difference that
has been existing for a long time yet.

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And the problem is that
the instruction sets are incompatible.

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And that is why code needs
to be compiled for either construction set.

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If you want to find the architecture that
you are using, you can use the ARC command.

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Alternatively, the CPU architecture is
also shown in the current kernel

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version in use Uname R
if you want to see it.

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Let me
show you.

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Okay, to start it, I would like to
run a program and that is my zombie program.

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What do we see? Well,
we see this error message.

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The error message is giving
me cannot execute binary file

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exec format error. Now what
is this exec format error?

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That is indicating that I'm
running it on the wrong architecture.

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Hey, does the file
utility give me anything?

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Let's use file
on which zombie.

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And there you can
see that this is a

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binary that has been
compiled as x86 64.

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And that's exactly the problem, because if
you use file no matter which other program,

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like PASSWD for instance, there you can
see that is compiled for ARM ARC 64.

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So it's in the binary for
which architecture they have been created.

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So you can use ARC
to figure out your architecture.

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And as you can
see, I'm on arc.

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And you can also use UNAME R.
UNAME R is also showing you that in

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the kernel version. So I'm on the
ARC kernel version and that's providing enough information.

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And it means that I can only
use programs that have been compelled for arm.

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Now I can tell you from my own practice, because
I'm using virtual machines on top of the ARC architecture.

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Most programs on Linux by default work perfectly
on Intel. When you are working on ARC architecture,

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every now and then doesn't happen too often,
but you might find some externally obtained programs that

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won't work and give you this exact format
error. And this is what is behind it.