Basic operation procedure is as follows:
- 1. Be loaded.
+ 1. Be loaded. However this is done, as the first thing we write a RETF
+ instruction to 0000:0000 and CALL FAR it (from 16-bit code), or
+ write a RET instruction to 0x00000000 and CALL it (from 32-bit
+ code), backing up the previous content of course, so that qemu+gdb
+ users can intercept via "b *0".
BIOS We are loaded to 0x07C00. The drive used to load us from
is passed in the DL register. The ES:BX and DS:SI regis-
7. The hardware is probed:
- + o Console devices: the default BIOS console (INT 10h, which may be
+ + Console devices: the default BIOS console (INT 10h, which may be
a MDA/MGA/Hercules, CGA/EGA or VGA CRT/LCD, plus DIN or PS/2 or
emulated keyboard) as well as up to four serial ports (via the
BIOS interface).
- + o Memory: ask the BIOS and probe page by page through the address
+ + Memory: ask the BIOS and probe page by page through the address
space, in case the BIOS reports wrong information.
- + o APM support
- + o PXE support
- + o Loadable Multiboot Modules (if any, they are moved off to safe
+ + APM support
+ + PXE support
+ + Loadable Multiboot Modules (if any, they are moved off to safe
locations and the virtual lmbm device and lmbmfs are set up)
- + o Floppy disc drives
- + o Hard disc drives, including El Torito CD-ROM drives
+ + Floppy disc drives
+ + Hard disc drives, including El Torito CD-ROM drives
8. If a command line was passed, it is executed. If it contained a boot
command, the kernel is attempted to be loaded; otherwise, or if it
boot> machine mem -0x100000@0x00F00000
- regs Debugging command displaying register dumps.
-
oldbios Enable or disable the so-called "Old BIOS / Soekris
helper", which restricts boot from loading more than
one sector at a time from disc.
+ pxe Forcibly scan for a PXE boot ROM.
+
+ regs Debugging command displaying register dumps.
+
macro Displays the names of all currently defined macros. Up to four
can be defined, holding up to 256 characters.
auto-booting
tty Name of the active console device, for example:
- + o com0
- + o com1
- + o pc0
+ + com0
+ + com1
+ + pc0
stty [device [speed]]
Displays or sets the speed for a console device. If the baudrate
tion or the ability to stat files (especially remote filesystems).
Examples of valid image specifications are:
- + o fd0a:/bsd
- + o hd0o:/bsd.rd
- + o / (for "ls")
- + o hd0a:/ (for "ls")
- + o lmbm:/ (for "ls")
- + o cd0a:/boot/grub/stage2
- + o tftp:/bsd.rd.i386
- + o lmbm:/bsd4grml
- + o /bsd
+ + fd0a:/bsd
+ + hd0o:/bsd.rd
+ + / (for "ls")
+ + hd0a:/ (for "ls")
+ + lmbm:/ (for "ls")
+ + cd0a:/boot/grub/stage2
+ + tftp:/bsd.rd.i386
+ + lmbm:/bsd4grml
+ + /bsd
Disklabels are read from hard discs (BIOS drive >= 80h) by searching for
a primary MirOS partition first. The default partition type, 0x27, can be
gPXE, but no code yet. For now, gPXE can load boot using Mul-
tiboot, and any passed modules are handled via lmbmfs.
- ustarfs This filesystem will be implemented soon.
+ ustarfs This filesystem is currently only usable with the boot floppy
+ and assumes that the entire floppy disc (except, on sparc, the
+ MD disklabel) is a valid ustar archive.
-MirOS BSD #10-current October 24, 2009 7
+MirOS BSD #10-current August 6, 2010 7