### 2.1 Terminology ¶

In this section we explain and contrast some of the terms `ne` uses. Understanding these distinctions will go a long way towards making the rest of this manual make sense.

A file is a group of bytes stored on disk. This may seem rather obvious, but the important distinction here is that `ne` does not edit files; it edits documents.

A document is what `ne` calls one of the “text thingies” that you can edit. It is a sequence of lines of text in the computer’s memory—not on disk.2 Documents can be created, edited, saved in files, loaded from files, discarded, et cetera. When a document is loaded from or saved to a file, it remains associated with that file by name until the document is either closed or saved to a different file. Interactions between documents and files are handled by the commands under the ‘`File`’ menu. The ‘`Documents`’ menu commands only deal with documents. See Menus.

Internally, `ne` holds its documents’ text in buffers. A buffer is a chunk of memory in which `ne` holds text. In addition to each document’s text, buffers hold any loaded or recorded macros, undo records, a copy of your last deleted line, a copy of all your previous responses to long input, and several other things.

#### Footnotes

##### (2)

Actually, it can be in a region of the disk used to simulate a larger memory. `ne` will switch to such a simulation whenever the computer’s memory is not sufficient for editing a file. This means, in particular, that out-of-memory errors can be caused by insufficient disk space, too.