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diff --git a/bootblocks/README b/bootblocks/README index e78097d..ab115e3 100644 --- a/bootblocks/README +++ b/bootblocks/README @@ -1,114 +1,165 @@ -To install the tarfile bootsector ---------------------------------- +Contents - Create the makeboot program: +1.0 ) Boot sectors +1.1 ) Master boot sector +1.2 ) Dosfs boot sector +1.3 ) Minixfs boot block +1.4 ) Tar boot sector +1.5 ) Skip boot sector +1.6 ) Panic boot sector -$ make makeboot +2.1 ) Booting i86 standalone executable +2.2 ) Booting Elks kernel +2.3 ) Booting Linux-i386 [b]zImage -Create the tarfile +-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=- -$ tar cvfV /dev/fd0 ENIAC monitor.out item2 item3 +1.0 ) Boot sectors -Make it bootable + These boot sectors are mostly designed for floppy use, the exceptions + being the MinixFS and Master boot sectors. -$ makeboot tar /dev/fd0 + The makeboot program makes them very easy to install just format the + disk add the correct filesystem then run a command like ... -Note, the distribution tar file is made using this procedure and can be booted -if uncompressed and copied onto a raw floppy. + $ makeboot minix /dev/fd0 -To install the dosfs boot sector --------------------------------- + As far as I know all boot sectors and programs are 8086 clean, with + the exception that, obviously, the Linux-i386 loader needs access to + extended memory. -$ make makeboot -$ makeboot dosfs /dev/fd0 +1.1 ) Master boot sector -or -$ make makeboot.com -C:\> makeboot dos a: + This MBR is a very simple one with no frills, being less that 254 bytes + long is can be used as an MBR for a disk with old style 'Disk manager' + partitions. All 16 partitions are bootable. - Place a Linux-8086 executable in the root directory of the floppy. +1.2 ) Dosfs boot sector -$ make monitor.out -$ mcopy monitor.out a:BOOTFILE.SYS + Install with makeboot, the boot sector requires the floppy to be double + sided and makeboot checks for this. This boot sector loads and executes + a binary BOOTFILE.SYS from the root directory of the floppy. The file + can be any length and is loaded at $07C00. Because of the load address + this boot sector can be configured to load another boot sector, for + example LILO can be succesfully used in this way. -or -C:\> copy monitor.out a:\bootfile.sys + In fact LILO can be succesfully used in this way on a 2M disk, but + you must create the floppy with the real dos 2M package as superformat + does not create correct bootable 2M disks. Also beware that mounting + a 2M floppy can ... be interesting ... - This works on my 3 1/5 floppy and my 5 1/4, and it _should_ work on - any double sided drive. (It does work on a 3.5/720k floppy too) - For single sided floppies you need to alter msdos.s (the heads var) - and remove the check in makeboot.c + Note this boot sector loads the executable 1 sector at a time, as far + as my testing has gone this is only significant on 8086 machines, all + others (286 8Mhz +) are fast enough to keep up at a 1-1 interleve. -To install the minixfs boot sector ----------------------------------- +1.3 ) Minixfs boot block - Make a minix filesystem on the floppy: + This boot block has varients for floppy and harddisk and works similarly + for both. For the hard disk it must be installed in the partition boot + block with a normal MBR in sector zero of the disk. This boot sector can + be installed with makeboot or simply by copying the 1k file to the start + of the partition (or floppy) to be booted. -$ mkfs -t minix /dev/fd0 1440 -or -$ mkfs -t minix /dev/fd0 1200 + The sector looks for a file or directory called 'boot' if it's a + directory it loads that and does the search again. When it finds a + file it loads it at location $10000 and executes it, beware this + is limited to a file size of 519k. - Make the bootblock program. + There is also support for a helper boot which mean this is the only + boot sector able to load an ELKS image (almost) directly. -$ make minix.bin +1.4 ) Tar boot sector -- Cool Man!! - Install it + This boot sector converts a tar file with a GNU Volume lable into a + bootable floppy image. The boot sector loads and executes the first + item in the tar file after the lable: -$ cp minix.bin /dev/fd0 + $ tar cvfV the_file.tar ENIAC monitor.out item2 item3 + $ makeboot tar the_file.tar + $ cp the_file.tar /dev/fd0 - Place a Linux-8086 executable in the root directory. + This sequence makes a bootable floppy that tar sees as a normal labeled + tar file but when booted from will load and execute 'monitor.out' at + location $00800 (Yes thats 2k!) -$ make monitor.out -$ mount -t minix /dev/fd0 /mnt -$ cp monitor.out /mnt/linux -$ umount /dev/fd0 +1.5 ) Skip boot sector - This works on my 3 1/4 floppy, and it _should_ work on any double sided - drive. Be sure to make the filesystem the full size of the floppy. + This bootsector displays a message then loads and executes the hard disk + MBR at location $07C00 +1.6 ) Panic boot sector -Booting a Linux-386 bzImage ---------------------------- + Displays the message 'PANIC! NO OS Found!' and freezes. -NOTE: This only works with bzImage files NOT zImage files. +-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=- -Take 1 msdos floppy. +2.1 ) Booting i86 standalone executable -$ makeboot dos /dev/fd0 -$ mount -t msdos /dev/fd0 /mnt -$ cp monitor.out /mnt/bootfile.sys + All the boot sectors (dos, minix, tar) check for a ELKS-i86 magic number + at the start of the file they load and will correctly set the segment + registers before calling. The executable should be a 'standalone' + executable compiled with 'bcc -Ms ...' or similar. -$ cp /usr/src/linux/arch/i386/boot/bzImage /mnt/vmlinuz -$ echo 'root=/dev/ram ramdisk_file=ramdisk.gz mem=80M' > /mnt/vmlinuz.cmd -$ cp /archive/ramdisk.gz /mnt/ramdisk.gz -$ umount /dev/fd0 +2.2 ) Booting Elks kernel -The stuff about ramdisk is only if you want an init ramdisk. You can also use: + Only the minix boot sector can directly boot an elks kernel and even that + needs a helper function because of the complexity. The helper is called + 'minix_elks.bin' and needs to be copied onto the disk as '/boot/boot' + with the ELKS image copied on as '/boot/linux'. This works, with the + correct boot block, on either floppy or harddisk. -vmlinuz.app: Arguments prepended to the Linux command line. -vmlinuz.cmd: Arguments appended to the Linux command line. -vmlinux.dfl: Arguments appended to the Linux command line. +2.3 ) Booting Linux-i386 [b]zImage -If there's a *.cmd file you won't be asked anything. If there's a *.dfl or -neither you'll be asked: + None of the boot blocks can _directly_ boot a Linux-i386 kernel the + program 'monitor.out' must loaded by the boot sector and this can + load a zimage or bzimage from an MSDOS or Tar floppy. -vmlinuz: + This example is for and MSDOS floppy, Tar is very similer except that + 'monitor.out' must be the first file in the tar and can have any name. -where you can type a command line to override the *.dfl file. If there's -a *.cmd file the *.dfl file is ignored, the *.app file is placed at the -start of the line whichever you do. + Note also for a tar file the 'ramdisk.gz' file must start on the first + disk but can extend across as many floppies as is needed. -If the file isn't called 'vmlinuz' you can still boot it by typing "=linux" -at the prompt '>' where 'linux' is the name of the bzImage file. + $ mformat a: + $ makeboot dos /dev/fd0 + $ mount -t msdos /dev/fd0 /mnt + $ cp monitor.out /mnt/bootfile.sys -Escape or ^C will interrupt the boot and drop you to the '>' prompt. -Esacpe or ^C at the '>' prompt will reboot - (This may be a little sensitive :-) + $ cp /usr/src/linux/arch/i386/boot/zImage /mnt/vmlinuz + $ echo 'root=/dev/ram ramdisk_file=ramdisk.gz mem=80M' > /mnt/vmlinuz.cmd + $ cp /archive/ramdisk.gz /mnt/ramdisk.gz + $ umount /dev/fd0 -A file called 'help.txt' will be displayed upto the first line that starts -with a '%', chunks after that (seperated by '%'s) will be displayed when -the user presses a function key, home, page up or page down. (Note it's -best if you try to ensure 'help.txt' is completely contained on one track -so the file is entirely in the track buffer) + The stuff about ramdisk is only if you want an init ramdisk, if the ramdisk + name begins with a '+' the program will ask for another disk first. + You can also use: + + vmlinuz.app: Arguments prepended to the Linux command line. + vmlinuz.cmd: Arguments appended to the Linux command line. + vmlinux.dfl: Arguments appended to the Linux command line. + + If there's a *.cmd file you won't be asked anything. If there's a *.dfl or + neither you'll be asked: + + vmlinuz: + + where you can type a command line to override the *.dfl file. If there's + a *.cmd file the *.dfl file is ignored, the *.app file is placed at the + start of the line whichever you do. + + If the file isn't called 'vmlinuz' you can still boot it by typing "=linux" + at the prompt '>' where 'linux' is the name of the bzImage file. + + Escape or ^C will interrupt the boot and drop you to the '>' prompt. + Esacpe or ^C at the '>' prompt will reboot + (This may be a little sensitive :-) + + A file called 'help.txt' will be displayed upto the first line that starts + with a '%', chunks after that (seperated by '%'s) will be displayed when + the user presses a function key, home, page up or page down. + +-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=- + +Robert de Bath <rdebath@poboxes.com> 22 Mar 1998 |