1- Assembly Language Step-by-Step: Programming with Linux2 Oct 2009 by Jeff Duntemann or https://www.tutorialspoint.com/assembly_programming/
for beginner?
4- I need an advice about how to study assembly.
1- In what year of learning assembly language may i found jobs?
2- Which assembly jobs can i found after two years of learning assembly?

I'd cook with a high level programming lang and add the assembly as a topping.

Finding jobs that you can do BETTER if you know assembler is easy. Finding one with assembler as a requirement is rare. Finding one with that as the MAJOR requirement is VERY rare.

If you want to be a developer or software engineer, continue with assembler as it makes you THINK into the machine. An invaluable skill! But also learn at least TWO higher level languages. By the time you finish BOTH may be obsolete, but you will find that picking up a new language once you have mastered two is easier. With every language you add, learning the next is easier than learning the last.

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Years ago, I worked on an IBM operating system (VM/SP, VM/XA, VM/HPO) that was – at the time – coded entirely in assembly language. But, even then, IBM was moving to the use of a high-level language (of their own devising) instead.

Today, quite frankly, CPU architectures are not designed to work with programs that are "hand-coded." Instead, they are built to efficiently process the output of optimizing compilers, and CPU manufacturers such as Intel and AMD work very closely with compiler writers ... and, offer compilers of their own ... in order to transform typical programming-language constructs into efficient code, and to detect and "do the right thing for" any particular CPU model.

To see how assembly code is typically used these days, you need look no farther than the /arch subtree of the Linux kernel, where all "architecture-specific" programming will be found. You'll basically find two sorts of things there:

1. "Trampoline" code, which is used immediately after Linux is launched on a particular hardware system, in order to set up that hardware sufficiently to let it then "bounce into" the Linux environment.
2. Short subroutines, which implement specific low-level operations in the actual manner required by "this architecture."

These days, you basically don't find significant work being done "in assembly." Although "C" compilers have traditionally had the asm { ... } directive, Microsoft's latest compilers have actually taken it out(!).

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sundial is right. Except for a few subroutines where speed is of the essence and you make extensive use of specialized processor commands (like SSE or equivalent commands in a video compressor or something similar), you're much better off just using C. It's much more legible, maintainable, etc. Assembly, almost by definition, inevitably leads to almost incomprehensible spaghetti code and modern compilers know more about instruction scheduling, pipelining, and optimization than you do. Assembly was important back in the old days like early Macs. where everything was prototyped in Pascal and then hand compiled to Motorola 68000 assembly to squeeze everything out of old processors. This really isn't necessary any more.

Not that you shouldn't learn it, I took an assembly language class in college and it helped me a lot in understanding programming, but I don't really ever actually use assembly.

Also ... here is a link to Intel's online source of the eight(!) manuals which describe the external characteristics of their current microprocessors!

The IBM/360 "Principles of Operation" ("POP") manual consisted of one document designed to be printed using a line-printer.

Manuals describing other microprocessors – 6502, 68000, Z-80 – were similarly thin, and the architectures they described were relatively uncomplicated.

Architectures today are too complex for humans to write efficient code for them using manual methods. But, compilers can do so easily. In the aforementioned manuals, Intel describes how best to write the source-code for maximum optimizability. They provide compilers themselves, and they also work very closely with compiler-writers such as Microsoft and the gcc team.

I recommend that you spend some time in the /arch folders of the Linux source tree, not just for x86 but also for other architectures. You should know enough about x86 assembly to be able to read and understand the subroutines that you find in the proper subdirectories. But you need not expect to write one, yourself.

"Low-level operations" are also best done by using "well-known libraries" to do the actual work. These libraries have been carefully crafted and compiled to do the work, and it is known that they do so correctly.

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