All, I browsed thru the blocks on my `Museum Format' v6 disk image, and after a bit of work found a nice comment from the writers of the code: /* * Optimized RK-11/RK03/RK05/disk driver * * Copyright (c) 1975, the Children's Museum. * * [...] In this * format, block 0 is in its standard place so that * boot programs can be put there; blocks 1 through * NHRKBLK (2435) are located beginning at block #2436, * all remaining blocks are between block 1 & 2435. the * effect of this mapping is to centralize disk head motion * about the center of the disk. * the optimization is ideal for those RK's * which serve as both root device and swap device. It * is less than ideal, although probably still an * improvement over traditional form, for RK's used * exclusively as mounted file systems. So, after a bit of dd(1)ing, I had my two Museum Format v6 disk images into a form which could be read with a normal v6 system. Cheers, Warren