>> pdisk (from mklinux) is:
>> ftp://nandra.iri.co.jp/pub/NetBSD/macppc/pdisk.tar.gz
>> 
>> I've not finished porting, but it mostly work.
>
>Weird. For me, it won't read anything. It always gets a media error.

Did You try to use /dev/rwd0c?  Currently it works for regular file only.

work-around patch:

*** file_media.c~	Fri Jun  4 03:16:17 1999
--- file_media.c	Wed Jun  9 08:08:45 1999
***************
*** 221,227 ****
  	    off = llseek(fd, (loff_t)0, 2);	/* seek to end of media */
  #if !defined(__linux__) && !defined(__unix__)
  	    if (off <= 0) {
! 		off = 1; /* XXX not right? */
  	    }
  #endif
  	    //printf("file size = %Ld\n", off);
--- 221,227 ----
  	    off = llseek(fd, (loff_t)0, 2);	/* seek to end of media */
  #if !defined(__linux__) && !defined(__unix__)
  	    if (off <= 0) {
! 		off = LOFF_MAX; /* XXX not right? */
  	    }
  #endif
  	    //printf("file size = %Ld\n", off);