Re: [TUHS] Re: Porting Unix v6 to i386

I think that v7 would be far easier to port than v6. Although it's not much bigger than v6, the code is a lot cleaner, and there are less machine dependencies. One of the reasons for a lot of the changes between v6 and v7 was a conscious effort to make it more portable . The old assignment operators like '=+' changed to "+=". 'Unsigned' and 'long' data types are missing from v6 (and reflected in the kernel), so all integer calculations were 16 bits. Unsigned ops were done using 'char *'. v7 was ported to the Vax and the Interdata. ioctl is there, and the 'standard io' library. The file seek call in v6 had either block (512) or byte offsets, and v7 introduced lseek to replace it. Only 16 bits were used to store block numbers in inodes, so filesystem sizes were restricted (not a real problem since both v6 and v7 could run happily on a 2.5Mb RK05 disk, including swap space and c compiler). 'vi' ran under v7, but v6 only offered 'ed' (or variants like 'em') and 'qed' If you hadn't guessed, v7 is by far my favourite Unix variant. Lean, clean and without the latter clutter of supporting networking in the kernel.