Most linux kernels accept a “vga=” command line parameter, which will set the resolution to use during boot. This is a short list of video modes which can be used, given your kernel supports your video card well enough, and the video card can handle the resulution.
My computer has the correct resolution all the way from boot time, which makes text MUCH easier to read.
The following table shows the mode numbers you can input at the VGA prompt (actually these numbers are plus 0x200 to make it easier to refer to the table)
Colours 640x480 800x600 1024x768 1280x1024 1600x1200 --------+--------------------------------------------- 256 | 0301 0303 0305 0307 031C 32,768 | 0310 0313 0316 0319 031D 65,536 | 0311 0314 0317 031A 031E 16.8M | 0312 0315 0318 031B 031F
For convienence, here is the same table in decimal terms
Colours 640x480 800x600 1024x768 1280x1024 1600x1200 --------+--------------------------------------------- 256 | 769 771 773 775 796 32,768 | 784 787 790 793 797 65,536 | 785 788 791 794 798 16.8M | 786 789 792 795 799