noun
read-only; input-only
Computing term for a file mode or device that only allows reading or input, not writing or output.
このファイルは入力用で開かれているので、書き込みはできません。
This file is opened as read-only, so you cannot write to it.
読み取り専用 is a more common term for 'read-only' in general computing contexts.
Compound of 入力 (input) + 用 (for the purpose of). A straightforward technical term.