I have written a space invaders type program in Qbasic which uses GET and PUT graphics statements in XOR mode. Although not too bad, the program does slow down when the are lots of sprites whizzing about the screen. I once read a program in a magazine for the BBC computer which used assembly language to access an operating system routine to print the graphics more quickly. I would like to pass the x,y screen coordinates of my characters to an assembly language routine which would then display the character at that location. Is there a similar OS call for the PC ? Where can I find out how to use such a call ? Can I do it simply without having to read a complete introductory course in assembly language ?