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RISC OS 3.7 User Guide

Appendix F: Old-type screen modes

This appendix gives information about the numbered screen modes that were used with earlier versions of the RISC OS operating system. This information is only needed for backward compatibility purposes: for example, you may be using an old software application or game that demands a particular old type screen mode.

Display manager

This section gives a quick recap on how the new screen Display manager operates and where to find more information.

In the Screen configuration option of !Boot, the type of monitor used with your computer is defined. This controls the selection of resolutions used by the Display manager. The Screen configuration option of !Boot is described in Screen on page 40.

Use the Display manager to choose the display resolution and number of colours used by the desktop. The Display manager is described in the section Desktop colour and resolution.

The display options that your monitor can use depend upon the characteristics of your monitor. These characteristics are described in a special file called a ModeInfo file. This file is tuned to each monitor type and should not normally be changed. If there is no monitor type for your particular monitor you should contact your Acorn dealer for information.

Backward compatible screen modes

There are several reasons why you may want to use an old type screen mode;

• To play a game that demands an old type screen mode.
• To use an application that demands an old type screen mode.
• To generate old type sprite files using !Paint.

Choosing a backward compatible mode

You can choose old-type numbered modes from the Display manager icon bar menu. Choose the Mode window, delete any information in the box, and then type in the mode number you want to use. Click on OK.

If your chosen mode is not available, the Display manager will substitute one with the same number of colours.

Old type sprite files

Your computer uses a new sprite file format, the file type used to save !Paint pictures. However you cannot use one of these new format sprite files on a computer running RISC OS 3.1 or earlier. If you want to use a sprite on a computer running an earlier version of the operating system you should create it while using one of the backward compatible screen modes. Alternatively the graphic translator application !ChangeFSI can convert between sprite types.

Mode table

The table of modes on the following pages show:

• The mode number.
• The text resolution in columns rows.
• The graphics resolution in pixels, which corresponds to the clarity of the mode's display.
• The number of colours available.
• The monitor types that support that mode:

Monitor types are;

• 0 : Standard monochrome or colour monitor
• 1 : Multi frequency monitor
• 3 : VGA-type monitor
• 4 : Super VGA-type monitor

List of screen modes

This is the list of screen modes supplied with RISC OS. Third party suppliers may produce software and hardware that produces different video modes; such modes are not listed here.

Mode	Text resolution	Pixel resolution	Logical colours	Monitor types	Desktop mode	Notes
0	80 x 32	640 x 256	2	0,1,3,4	Yes	3
1	40 x 32	320 x 256	4	0,1,3,4	Yes	3
2	20 x 32	160 x 256	16	0,1,3,4	3
3	80 x 25	Text only	2	0,1,3,4	3,4,6
4	40 x 32	320 x 256	2	0,1,3,4	3
5	20 x 32	160 x 256	4	0,1,3,4	3
6	40 x 25	Text only	2	0,1,3,4	3,4,6
7	40 x 25	Teletext	16	0,1,3,4	3,4
8	80 x 32	640 x 256	4	0,1,3,4	Yes	3
9	40 x 32	320 x 256	16	0,1,3,4	Yes	3
10	20 x 32	160 x 256	256	0,1,3,4	3
11	80 x 25	640 x 250	4	0,1,3,4	Yes	3
12	80 x 32	640 x 256	16	0,1,3,4	Yes	3
13	40 x 32	320 x 256	256	0,1,3,4	Yes	3
14	80 x 25	640 x 250	16	0,1,3,4	Yes	3
15	80 x 32	640 x 256	256	0,1,3,4	Yes	3
16	132 x 32	1056 x 256	16	0,1	Yes	5
17	132 x 25	1056 x 250	16	0,1	Yes	5
18	80 x 64	640 x 512	2	1	Yes
19	80 x 64	640 x 512	4	1	Yes
20	80 x 64	640 x 512	16	1	Yes
21	80 x 64	640 x 512	256	1	Yes
22	96 x 36	768 x 288	16	0,1	Yes	1
23	High resolution monochrome monitor only
24	132 x 32	1056 x 256	256	0,1	Yes	5
25	80 x 60	640 x 480	2	1,3,4	Yes
26	80 x 60	640 x 480	4	1,3,4	Yes
27	80 x 60	640 x 480	16	1,3,4	Yes
28	80 x 60	640 x 480	256	1,3,4	Yes
29	100 x 75	800 x 600	2	1,4	Yes	1,2
30	100 x 75	800 x 600	4	1,4	Yes	1,2
31	100 x 75	800 x 600	16	1,4	Yes	1,2
32	100 x 75	800 x 600	256	1,4	Yes	1,2,7
33	96 x 36	768 x 288	2	0,1	Yes	1
34	96 x 36	768 x 288	4	0,1	Yes	1
35	96 x 36	768 x 288	16	0,1	Yes	1
36	96 x 36	768 x 288	256	0,1	Yes	1
37	112 x 44	896 x 352	2	1	Yes	1
38	112 x 44	896 x 352	4	1	Yes	1
39	112 x 44	896 x 352	16	1	Yes	1
40	112 x 44	896 x 352	256	1	Yes	1
41	80 x 44	640 x 352	2	1,3,4	Yes	1,3
42	80 x 44	640 x 352	4	1,3,4	Yes	1,3
43	80 x 44	640 x 352	16	1,3,4	Yes	1,3
44	80 x 25	640 x 200	2	1,3,4	Yes	1,3
45	80 x 25	640 x 200	4	1,3,4	Yes	1,3
46	80 x 25	640 x 200	16	1,3,4	Yes	1,3
47	45 x 60	360 x 480	256	1,3,4	Yes	1,7
48	40 x 60	320 x 480	16	1,3,4	Yes	1,7
49	40 x 60	320 x 480	256	1,3,4	Yes	1,7

Notes:

1. These modes were not available in RISC OS 2.00, nor (except for mode 31) were they available in RISC OS 2.01.
2. These modes are not available on early models of RISC OS computers (i.e. the Archimedes 300 series, 440, and 400/1 series, and the BBC A3000).
3. If you are using a VGA or Super-VGA-type monitor, these modes are all displayed on a screen having 352 raster lines. Where a mode has fewer than 352 vertical pixels, it is centred on the screen with blank lines at the top and bottom. Because of their appearance these modes are known as letterbox modes. The refresh rate is 70Hz.
4. These modes provide compatibility with BBC and Master series computers.
5. In these modes circles, arcs, sectors and segments do not look circular. This is because the aspect ratio of the pixels is not in a 1:2, 1:1 or 2:1 ratio.
6. These are gap modes, where the colour of the gaps is not necessarily the same as the text background.
7. These modes were not available in earlier versions of the operating system.

256 colour modes

In 256 colour modes, there are some restrictions on the control of the colours. Only 64 base colours may be selected; 4 levels of tinting turn the base colours into 256 shades. Also, the selection from the colour palette of 4096 shades is only possible in groups of 16.

Monitor types

If you attempt to select a mode which is not appropriate to the current monitor type, a suitable mode for that monitor is used.

Monitor types and screen modes

Not all monitors can display all of the old type screen modes. The following table lists the screen modes each monitor can display:

Mode	Multi-freq monitor	VGA & LCD monitor	Super VGA monitor
0 - 15	Yes	Yes (See Note 1)	Yes (See Note 1)
16,17	Yes	No	No
18 - 21	Yes	No	No
22	Yes	No	No
23	Not supported	Not supported	Not supported
24	Yes	No	No
25 - 28	Yes	Yes	Yes
29 - 35	Yes	No	Yes
32	Yes	No	Yes
33 - 36	Yes	No	No
37 - 40	Yes	No	No
41 - 46	Yes	Yes	Yes
47	Yes	Yes	Yes
48-49	Yes	Yes	Yes

Note 1: VGA and Super VGA type monitors can display modes 0 to 15 with reduced height (letterbox mode). These modes are retained for compatibility.