I wrote bos.s and msys.s from scratch. I am not aware of any binaries or source for these. bos is written in an entirely position-independent manner so that it can be compiled with a v1 assembler, v2 assembler, etc. and still run when loaded at location 54000 in core. Other than the option to load a paper tape, I believe this to be as true to V1 as possible. msys was implemented to be as true to V1 as I believed possible. It copies images directly from disk without modifying them, as I believe the original V1 msys did. There is no header kludging, since a V1 a.out UNIX kernel should be bootable without modification. For wunix (warm unix), I took the build/loadfile, stripped off the first 6 bytes, then copied the next 16K bytes, just as the boot/installboot script does. For building under UNIX itself, there are a variety of strategies. Here is my list, in order of preference: 1. Use the V1 assembler. This will produce a 12-byte header that is exactly compatible with the kernel source as it appears in the listing. As many people on this are aware, the first 12 bytes get manually patched by the UNIX code when it starts up. But, I don't think the V1 assembler exists anywhere, or at least not that has been found. That kind of makes this option moot. 2. Modify the V2 assembler to produce V1 binaries. If the V2 assembler can be built from sources, then it should be straighforward to edit it to produce V1 binaries (i.e. 405 instead of 407). This would allow a kernel in the true spirit of V1 to be created, then copied into the boot area by msys. It would also allow other programs to all be created as V1 binaries, which has a lot of attraction to me. 3. Modify msys.s to be msys2.s to strip the 407 header and also truncate the copy to not overrun the size of the area being copied into (1K, 6K, 6K, 3K). I just tested a modified version of this and attached it below, since that should help to get things going; but I really think that option #2 would be nice to have eventually. Note to use msys2, you need to copy build/a.out to fs/usr/boot/unix.out, and to put msys2.s into fs/usr/boot/msys2.s. Then after you boot, do: chdir /usr/boot as msys2.s mv a.out msys2 msys2 u unix.out I'll clean up the source and send a complete fs/usr/boot out later tonight. James Markevitch --------------------------- fs/usr/boot/msys2.s ------------------------- / msys2 -- copy file to RF read only slot / / re-creation, based on description in UNIX_ProgammersManual_Nov71.pdf, / page 7-06, BOOT PROCEDURES (VII) / 5/9/08 jam(a)magic.com / 5/17/08 jam(a)magic.com -- hacked to copy 407-format a.out files / b bos 1700 / u warm unix 1704 / 1 cold unix 1734 / 2 unassigned 1764 mov sp,r5 mov (r5)+,r3 / argc cmp $3,r3 / must be 3 bne badcmd / else error tst (r5)+ mov (r5)+,r4 / get first arg cmpb (r4),$'b bne 1f mov $1700,r3 mov $4,r4 br 2f 1: cmpb (r4),$'u bne 1f mov $1704,r3 mov $30,r4 br 2f 1: cmpb (r4),$'1 bne 1f mov $1734,r3 mov $30,r4 br 2f 1: cmpb (r4),$'2 bne badcmd mov $1764,r3 mov $14,r4 2: / open file mov (r5),r5 mov r5,0f sys open; 0:..; 0 bes error mov r0,r1 sys seek; 20; 0 bes error / open rf0 and seek to correct block sys open; disk; 1 bes error mov r0,r2 mov r3,0f sys seek; 0:..; 0 bes error / copy file from file to disk one block at a time 1: mov r1,r0 sys read; buf; 512. mov r0,r5 mov r2,r0 sys write; buf; 512. bes error dec r4 beq 3f tst r5 bne 1b 3: sys exit error: mov $1,r0 sys write; 1f; 2 4 sys exit 1: <?\n> badcmd: mov $1,r0 sys write; 1f; 2 4 sys exit 1: <?\n> disk: </dev/rf0\0> .even buf: .=.+512.