🚀 go-pugleaf

>I am a little confused about what the current state of the art in rom
>monitors is. We have the original WBC monitor, we have the "autoboot
>monitor" and we have the forth monitor.

Ok, I'll talk about the autoboot monitor.

  Features beyond (added to) the "standard" (OR WBC) monitor of Summer 90.

  A) SCSI tape routines including "backup" and "restore" 
      (Added by Charles Rennolet)

  B) disk partitions, boot images, and autoboot and boot commands.
      (Added by me.)


  For the autoboot monitor, you must have a disk label on your disk.
   The current version uses the BSD disklabel.  One of your partitions
   must be labeled "boot images".  The boot images will contain executables
   of any stand-alone program that you want.  After the BSD disklabel is
   a table of "boot images".  Included in the information is an ascii name,
   the location in ram of where to load the image, the length of the image
   and the run address.  The "boot" command uses the image information to
   execute a "read" command followed by a "run" command.  There is NO knowledge
   of ANY file system format.  Included are commands to list the partition table
   and to list the images.  The number of images you have on your disk is 
   limited only by the size of the image partition and the size of the images.
   I have had up to 8 or 9 images when I was testing new changes to the minix
   kernel.   One image can be identified as the "default" image to boot IF the
   auto feature is enabled and is engaged.  You can boot any image by using
   the boot command.  Even if the autoboot feature is enabled in the rom, you
   can specify that there is no default image and the autoboot code will not
   boot any image.

 There is a program called "hdsetup" that I use under minix to set up my disk for
   the autoboot monitor.  It will setup both the BSD disklabel and the image
   table.  (It may not be complete for BSD, but will currently work for minix.
   Once BSD is working, hdsetup may be useful only for work with the image table.)
   hdsetup can add or delete images from the image partition.

 A typical setup for use with the autoboot monitor is (512 byte sectors):

   partition 0: sectors 0 -> end of the disk
   partition 1: sectors 2 -> 2047  (boot images)
   partition 2-7: sectors 2048 -> and on as you want file systems or swap
	 partitions.


Since I have been using the autoboot monitor I have used the raw read
command only a few times to read a bootable image.  And when I did,
(usually to change some data in the image before running it) I used
the "images" command of the autoboot monitor to help me find the image
and know how many sectors to read.

This "autoboot" method should allow the pc532 to boot ANY OS.  You
could write a small standalone program to put in the image partition
that could read a BSD file system and boot the real OS from off the
BSD file system.


--Phil