The Acorn Electron had seven screen modes (0 to 6) allowing different combinations of text columns, text rows, graphics resolution and number of colours on screen. The BBC Models A and B also had Mode 7. The combinations were:
Mode	Graphics Resolution (Pixels)	Text Columns x Rows	Max Colours on Screen	RAM Needed
0	640 x 256	80 x 32	2	20 KB
1	320 x 256	40 x 32	4	20 KB
2	160 x 256	20 x 32	16	20 KB
3	Text only	80 x 25	2	16 KB
4	320 x 256	40 x 32	2	10 KB
5	160 x 256	20 x 32	4	10 KB
6	Text only	40 x 25	2	8 KB
7	Teletext compatible Text and block graphics only	40 x 25	8	1 KB