[Unix-jun72] Anyone working on V1 mkfs?

Warren Toomey wkt at tuhs.org
Thu May 1 20:58:08 EDT 2008


On Thu, May 01, 2008 at 08:33:35PM -0400, Brad Parker wrote:
> The hardware bootstrap process is in the man pages - it looks somewhat
> rational.  I have not studied it but I think the fun part will be making
> a dectape image which has the binaries to be populated.

I was hoping to have a populated filesystem to start with, because we
should be able to run V1 bin/check using Apout, to check the filesystem.
 
> Having said all that, having a working mkfs would be would be very handy
> and would make setting up  a boot disk much easier!

The V1 manual for filesystem(5) say "Blocks 0 and 1 are collectively known
as the super-block for the device". Can you confirm that block 0 is part
of the super-block, i.e. it's not reserved for bootstrap code? If block 0
is the super-block, it should contain a word (# of bytes in free-map) followed
by lots of 0177 bytes, which are the free-map.

On another note, I thought of taking V6 mkfs.c as a start-point to rewrite
V1 mkfs. I'm trying to work out what f_m and f_n do:

        if(fsys[n] == 'r') {
                if(f == 'k') {
                        f_n = 24;	/* RK, why these numbers? */
                        f_m = 3;
                }
                if(f == 'p') {
                        f_n = 10;	/* RP, why these numbers? */
                        f_m = 4;
                }
        }

Finally, are we going to use RK03 or RK05, as the sizes are different?

Thanks all,
	Warren



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