128 1 1 1 1 1 1format gap length 80 80 80 80 80 80format fill character 0f6h 0f6h 0f6h 0f6h 0f6h 0f6hhead settle time 01h 01h 01h 01h 01h 01hmotor on delay 1 8 sec 0 0 0 0 0 0maximum track 3 7 13 28 56 56data rate 80h 80h 80h 80h 80h 80h__________________________________________________________________________ the disk parameters for the rom correspond to the 256 k column for the two concatenated rom 39 s the computer of the preferred embodiment also has a provision for connection to an external disk drive not shown the bios must therefore be able to distinguish between a request for an external disk drive and a request for an internal ram card or ms dos rom if the request is for an external drive the bios acts in a standard manner to access that device if however the request is for ms dos or for data or program steps stored on the ram cards the bios performs a specially designed program sequence referred to below as the 34 ram rom driver 34 which makes the ram cards and or the ms dos rom 39 s appear as floppy disks to the software making the request as shown schematically in fig3 the sequence of events for a software disk service request is as follows 2 bios determines whether the request is for a physical floppy disk or a ram card ms dos rom if an external drive is attached to the system the internal ms dos rom 39 s are.