VMODE, an internally defined number variable, controls the mode of the video display system.
Changing VMODE automatically changes the state of the video system, as well as adjusting a
number of related CIGAL variables associated with the screen dimensions and cursor control.

The allowable values for VMODE will depend on the system's video hardware. Illegal values are
generally ignored, however, some video system hardware can cause a system hang-up if set to an
illegal value. Exercise some caution when changing this parameter.

The meaning of the different VMODE values is as follows:
VMODE values 0 to 19 correspond to video modes 1 to 19 as defined by IBM.
VMODE value 20 is used to put a Hercules graphics adapter into graphics
mode.
VMODE values 51, 84, 97, and 103 are used for Super VGA modes.

VMODE Graphics Text_Dims Graph_Dims Wdsiz Base_Address Mem_Size Monitors
0 - 40 x 25 320 x 400 4 BW 0B800h 800h
1 - 40 x 25 320 x 400 4 0B800h 800h
2 - 80 x 25 640 x 400 4 BW 0B800h 1000h
3 - 80 x 25 640 x 400 4 0B800h 1000h
4 1 40 x 25 320 x 200 2 0B800h 2000h
5 1 40 x 25 320 x 200 2 BW 0B800h 2000h
6 1 80 x 25 640 x 200 1 BW 0B800h 2000h
7 - 80 x 25 720 x 400 1 BW 0B000h 1000h
8 - 20 x 25 160 x 200 4 0B000h 0
9 - 40 x 25 320 x 200 4 0B000h 0
10 - 80 x 25 640 x 200 2 0B000h 0
13 1 40 x 25 320 x 200 4 0A000h 2000
14 1 80 x 25 640 x 200 4 0A000h 4000
15 - 80 x 25 640 x 350 1 BW 0A000h 14000
16 1 80 x 25 640 x 350 4 0A000h 14000
17 1 80 x 30 640 x 480 1 BW 0A000h 0
18 1 80 x 30 640 x 480 4 0A000h 0
19 1 40 x 25 320 x 200 8 0A000h 0
20 1 80 x 25 720 x 348 1 0B000h 8000h
35 (23h) - 132 x 25 1056 x 350 4 0B800h 256k 1,2,5
39 (27h) - 132 x 25 1056 x 350 1 0B000h 256k 1,2,5 * 51 (33h) - 132 x 44 1056 x 352 4 0B800h 256k 1,2,5
55 (37h) - 132 x 44 1056 x 352 1 0B000h 256k 1,2,5
83 (53h) 1 800 x 600 4 0A000h 256k 1,2,5 * 84 (54h) 1 800 x 600 4 0A000h 256k 5 * 97 (61h) 1 640 x 400 8 0A000h 256k 3,4,5
98 (62h) 1 640 x 480 8 0A000h 512k 3,4,5
99 (63h) 1 800 x 600 8 0A000h 512k 5
101 (65h) 1 1024 x 768 4 0A000h 512k 4,5 *103 (67h) 1 1024 x 768 2 0A000h 256k 4,5
Monitors: (1) TTL mono (2) EGA (3) VGA (4) IBM 8514 (5) Multisync