Why don't you #embed?

Because the linked article is from 2013.

Embedded systems have generally either limited resources such as processing, memory, bus interfaces, or real time operations such as scheduled tasks in short periods, hard/soft deadlines. These sort of requirements address best performance and small footprint, so you mostly need programming languages that meets them.

I wanna develop the small desktop games via Godot for Linux and HTML5 in new year. I started to learn it and go on. And i participated goodreads challenge to read 5 books in new year. The most will be related to programming and operating system. I want to learn go programming, and read all chapters of Tanenbaum books about operating system and distributed systems.

is it RTOS?

If by "RT" you mean "not RT" then yes ;)

:) i dont like the book.

could you perform a benchmark?

in current tech, using sleep is still poorly design.

i use 13.3' macbook pro and it's always enough for coding, reading and watching. i agree that it is still too heavy, in fact the air is more preferable than it.

command line

in fact, xcode and emacs are not in same category exactly. emacs isn't complete ide, it is full-featured text editor. because you think it is an ide, it has some lack. if you work on mac osx, xcode may be more appropriate for your demand.