Confused about the resolution

[JohnPublic]

Hello I'm reading an NES doc which states this (Note, this is all relative to NTSC)

The NES resolution is 256x224. There are 262 scanlines per frame, 20 of which are V-Blank.

First off, how does that make any sense, 262 scan lines? how can that be over the resolution of 224? Even without the V-Blank, thats 242 which is not even near 224.

Whats the true resolution here? also, is there overscan?

Also, just to make sure, is every line drawn in order? It doesn't do anything funny like draw every other scanline right?

[tokumaru]

The vertical resolution of the NES is 240 scanlines, not 224. Don't be fooled by emulators that crop the top and bottom 8 scanlines. And yes, the total is 262: 20 are VBlank, 1 is pre-render, 240 are rendered and 1 is a dummy.

If this doc says the resolution is 256x224, you should stop reading it right now. Who knows what else could be wrong?

[CartCollector]

This document (search for "Frame rendering details") has a detailed description of the scanlines rendered during a frame. The reason that a lot of documents have the NTSC resolution as 224 scanlines is that most NTSC TVs are unable to display the full 240 scanlines.

[Petruza]

Well, there are 240 actual scanlines rendered to the screen, although the first and last 8 aren't usually seen on the screen of TVs and emulators.
the remaining VBlank, and the other 2 Tokumaru mentions, aren't really lines of pixels rendered anywhere, but rather the time that it would last if they where scanlines rendered. Right?

[tepples]

Well, there are 240 actual scanlines rendered to the screen, although the first and last 8 aren't usually seen on the screen of TVs and emulators.

I worked out exactly how much of the screen "should" be visible: Overscan