hard copy of the image as shown by the video display 26 and as defined by the image data stored in a video image memory 34 in the random access memory ram 18 of fig1 the basic disk operating system bdos 28 is preferably of a type which is generally characterized as being non reentrant such as those sold under the tradename control program monitor cp m by digital research and microsoft disk operating system sold by microsoft such non reentrant basic disk operating systems bdos are suitable for use in computers such as the ibm pc ibm xt dec rainbow t i professional and like computers therefore although a hard copy of the image displayed by the video display 26 may be provided immediately by the printer 22 upon the depression of the print key to provide the print key request 52 since only the basic input output system bios 36 is utilized it is not possible to interrupt the basic disk operating system bdos 28 to transfer bit mapped image data from the video image memory 34 to the disk 16 in order to enable a hard copy to be made after the termination of the applications program 38 by the printer 22 recalling the bit mapped image data stored by the disk 16 referring now to fig4 there is shown a basic system software organization for the computer system 10 of fig1 incorporating the image saving routine of this invention as shown at 30 in conjunction with the image saving routine 30 there is also provided a basic disk operating system bdos stub as shown at 54 and a video stub as shown at.