When I'm in a text document and I want to go to the next page I have to scroll DOWN.
When the DOS prompt is at the bottom line of the screen and I push the <enter> key the screen scrolls. Is this ScrollUp or is this ScrollDown

In both cases what happens on the screen is exactly the same. The contents are moved upwards and a new (blank) line is displayed at the bottom. An action that video bios function 6 calls 'Scroll window up'.

I'm currently writing a manual of some kind and I would want it to be as exact as possible. Many authors circumvent this problem by never mentioning any direction!

It depends upon your point of view.

Page Down ---> Screen image goes up
Scroll Down ---> Screen image goes up

When you are in text document and you want to go to the next page, you have to MOVE DOWN. But the screen in this moment SCROLL UP. The movement and the scroll are always in different directions. Note that the windows scrollbars actually accept movement commands, not scrolling commands. Moving commands are related to some caret type of element.

In the same time, there is a "panning" type of commands - used for example in PDF readers. In this case you are moving the whole document. In this case, the directions of the scrolling and panning are identical

> Note that the windows scrollbars actually accept movement commands, not scrolling commands

...

> When the DOS prompt is at the bottom line of the screen and I push

Are you in DOS ?

> I'm currently writing a manual

About what?

> ScrollUp = ScrollDown ?

DOS and BIOS can only scroll up. Text vanishing at screen top is lost forever.

> I want to go to the next page I have to scroll DOWN.

NO. You push PAGE_DOWN and scroll up.

But when the rows of the textscreen scrolls up, then the bios does not use a smooth-scrolling of each scan line with adjusting the start address of the row scan register inside of the CRT controller.
So i have written an example of a DOS-textviewer(16 bitmode) for the textscreen with 80 collums and 50 rows using a smooth scrolling.

Hints: The length of a textfiles should be 64 KB or lower.
The comments in the sourcefile are only written in the german language.
www.alice-dsl.net/freecracmaps/Tool/TEXT-OUT.ZIP

Dirk

So basically it comes down to the person giving a command (page down) and the screen performing an action (scroll up).
The subject of the sentence is thus all-important!
Thanks for this clarification!



BIOS actually has functions for both directions.
Function 6 Scroll Window up.
Function 7 Scroll Window down.
Normal DOS console operations will obviously only scroll up.



I'm kind of a DOS addict and so I'm writing a DOS-like OS which naturally needs a manual.