> For the complete documentation index, see [llms.txt](https://computerscienceeducation.gitbook.io/co-lab-manual/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://computerscienceeducation.gitbook.io/co-lab-manual/reference-documentation/input-output.md).

# Input/Output

Doing I/O may be quite tricky, even more so in Assembly. Normal processes do not have permission to access the hardware I/O devices directly, so the input and output must be handled by the operating system. Instructing the operating system to do so is typically done through so-called *system calls*, that hand control over to the kernel until the action is performed.

However, as you may have guessed, different operating systems have different ways of... well... *operating*. Luckily, the C Standard Library is available on essentially any major operating system you might run on your device and it offers abstractions for I/O that hide the underlying system calls. Furthermore, the functions of the C Standard Library (like `printf` and `scanf`) come with many niceties, like ASCII-to-integer (or *vise versa*) conversions.