Hi, you are not the first one who is planning FreeDOS ports for embedded x86:
http://fd-doc.sourceforge.net/faq/cgi-bin/viewfaq.cgi?faq=incoming/277 This FAQ entry contains a detailled description of the needed BIOS services for the kernel. You can remove some of them by modifying the kernel a bit. You should not try to remove all - it is easier to keep them in the BIOS, even if this means that you have to improve your BIOS first. If you want to use non-BIOS disks, you will have to load a driver which offers simple sector read / write. You can load the kernel into RAM and start it, but then, you need at least a very tiny and simple disk (could be a disk image in ROM, as in ROMOS) with already active drivers to provide files like config sys. In config sys, you can load the abovementioned driver (if the disk is partitioned, it would have to process the MBR itself - but the KERNEL can do all the FAT processing for you) to gain access to more disks. Summary of required services: Int 0x11 / 0x12 (trivial) provide system information Int 0x14 / 0x17 are used to init and access COM and LPT ports, but only if system information told that such ports exist. Int 0x19 can be used to reboot, but is not really needed. Some values at 0x40:?? have to be present for FreeDOS. For DISK access, functions 0, 1, 2, 3 and 8 should be present of int 0x13 (more if you prefer LBA access instead of CHS). Read MEMDISK of SYSLINUX sourcecodes for an example. For KEYBOARD access, int 0x16 functions 0, 1, 2 are needed, for modern keyboards also 0x10, 0x11, 0x12. For SCREEN access, int 0x10 functions like 0x0e (TTY) are used, but you should add a few more like 2, 9 and some status functions / cursor movement. For CLOCK access, int 0x1a is needed, and 0x40:0x6c has to do the usual timer tick - many DOS programs expect that. The int 0x1e contents should tell about the geometry of your (possibly simulated) floppy. Eric ------------------------------------------------------- SF email is sponsored by - The IT Product Guide Read honest & candid reviews on hundreds of IT Products from real users. Discover which products truly live up to the hype. Start reading now. http://productguide.itmanagersjournal.com/ _______________________________________________ Freedos-kernel mailing list [EMAIL PROTECTED] https://lists.sourceforge.net/lists/listinfo/freedos-kernel
