This is the stock BDOS and CCP from the simh Altair disk image.  My BIOS is
called JCWBIOS.MAC, and doing a 'DO BUILD' will build it.  It does not write
to the disk, just builds the CPMBOOT.COM file.  This gets written to the CF
starting at LBA sector 0.  The DPB for the CF reserves the first 16K of each
logical disk for boot code.
