CP/M for the N8VEM (with 1.44Mb floppies) The zipfile JC070510.ZIP was created on a DOS system. It contains all the source code and tools to make a CP/M 2.2 system ROM for the N8VEM single board computer which is capable of reading and writing 1.44Mb 3.5" floppy disks. All credit for the CP/M implementation goes to Digital Research, Andrew Lynch, and Dan Werner. All I did was modify the disk I/O routines to use the interrupt system. ****** TO USE THIS DISTRIBUTION, THE J1 (interrupt) JUMPER ON THE DISK I/O BOARD MUST BE INSTALLED. ****** The best way to make the ROMIMAGE.BIN, and other BIN files is with Microsoft NMAKE.EXE. If you don't have NMAKE, then use the BUILDROM.BAT file. Note also the NEWDISK.BAT and WR.BAT command files. The former zaps a formatted floppy to make a blank CP/M file system. The latter writes a boot record to the beginning of a disk. ********************************************************************** Differences: The CP/M A: and B: drives have been swapped in this version. A: is now the RAMdisk, and B: is now the Floppy drive. F: is the same ROMdisk; likewise G: ********************************************************************** Directions: Edit the DSKY/UART selection at the top of BLOADER.ASM. Edit the sysgen options at the top of CBIOS.ASM. Enabling Floppy support alone supports 720K floppies with the modified disk driver; a second line ups the size of floppies to 1.44M. Then do your NMAKE or batch build. Tip: You don't have to burn the ROM yet. OOPS!!! Yes, you must burn a ROM. The new code will not run with the J1 interrupt jumper OFF; and the old code will not run with the jumper ON. You just can't have it both ways. BLOADER appears quite solid with the new code. So once you have the new version up (it will boot both 720K and 1.44M), you can easily tinker with the CBIOS or any- thing else: just boot from a floppy, DD or HD. ********************************************************************** Feedback, good or bad, should be directed to: John Coffman 05-Jul-2010