On Fri, Jan 6, 2012 at 12:25 PM, David Riley <fraveydank at gmail.com> wrote:
So wait, then, what's the difference between a /23
and a /23+ if not the 22-bit addressing? ?I was led to believe that was it.
Just KDF11-A vs KDF11-B... KDF11-A may or may not be 22-bit (only Rev
A is 18-bit). All -B are 22-bit. Dual-height CPU only vs Quad-height
CPU plus dual SLU plus on-board Boot ROMs.
If you are building a system from scratch and have an up-rev KDF11-A
plus a couple of serial ports (like half of a DLV11-J) plus a
Bootstap/terminator board then compare that to a /23+ system, the
effective difference is that the /23+ system will have fewer boards to
do the same thing and more open slots. No effective difference from a
software standpoint.
One can also assemble a KDF11-A system in one of the oddball narrow
backplanes that originally shipped with the LSI-11/2 where a KDF11-B
won't fit, but that's still just packaging.
A minimal /23+ system could be as little as 2 modules - KDF11-B plus
memory - use the second SLU for a TU58 or TU58 emulator and you could
boot RT-11. A /23 system will have more boards.
-ethan