Re: [TUHS] v6tar from v7 on v6, too large?

Now that I think about it, the linked systems that are part of the V6 distro tape are all linked to run on an 11/40. They will boot and run OK on a more powerful machine (/45 or /70), but they will act like they are on a /40 - i.e. no split I+D support/use (user or kernel). So to get split I+D support, you need to build a new Unix binary, with m45.s instead of m40.s. If you haven't done that, that's probably what the problem is. Aside: V6 comes in two flavours: no split I+D at all, or split I+D in both the kernel and user. For some reason that I can't recall, we actually produced an 'm43.s', BITD at MIT, which ran the kernel in non-split-I-D, but supported split I-D for the users. I wish I could remember why we did this - it couldn't have been to save memory (the machine didn't have a great deal on it when this was done - although I have this vague memory that that was why we did it), because running split I+D in the kernel does not, I think, use any more physical memory (provided you don't fiddle with the parameters like the number of buffers) than running non-split. Or maybe it does? One possible reason was that the odd layout of memory with split I+D in the kernel made debugging kernel code harder (we were doing a lot of kernel hacking to support early networking work); another was that we were just being conservative, didn't need to extra space in the kernel that I+D allowed, and so didn't want to run it. Noel