[TUHS] Upgrading from 11/40 to 11/45 in Unix v6

Will Senn will.senn at gmail.com
Mon Dec 31 13:31:34 AEST 2018

> On Dec 30, 2018, at 8:43 PM, Clem cole <clemc at ccc.com> wrote:
> The primary difference between the 11/40 class and 11/45 class is separate I/D space which I sometimes refer to as the 17th address bit because it allows you a full 64k of data space as well as a 64k of instructions space.  

Do you know of some commonly used at the time v6 programs that needed that much space?

> After you are booted, a 45 class machine will run 40 class binaries unchanged.  40 class machines can not run a.outs that are seperate I/D.

Good to know.

> You’ll probably want to configure a kernel for the 45 class machine.  Look at the differences in the *.s files in the kernel. IIRC there is a different file for 40 class and 45 class systems

I read about this in ’Setting up Unix Sixth Edition” and I see the source comments. It looks pretty straightforward to configure the system for separate I/D. Is there any material difference between doing it at install time vs having run on 11/40 for a while and moving the disk over to the 11/45 later?

On a related note, how difficult is it to copy the system from rk to hp? I know I can rebuild, but I’m sure there’s a quicker/easier method...

> That said if you running the simh I would recommend going all the way to an 11/70 configuration because you can set it up for 4M of main memory.

Maybe this will be the next upgrade :).

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