10 Feb
2016
10 Feb
'16
3:19 a.m.
Jerome -- good point about the IOPAGE. Maybe I'll get an 8kw and 16kw board -- that
gives me 28kw with the included 4kw. I have no specific software so I don't need to
tinker with reducing IOPAGE.
Rich
Sent from my iPhone
On Feb 9, 2016, at 10:47 PM, Jerome H. Fine
<jhfinedp3k at compsys.to> wrote:
Rich Cini wrote:
Thanks guys. This is really helpful. I was
getting confused between the M8044 and M7944 boards. Max memory for the LSI-11 is 32kw,
right?
Correct, the maximum memory on a board is 32kw.
For an LSI-11 (aka PDP-11/03) without any MMU hardware,
the actual maximum memory that can be accessed must also allow
for the IOPAGE registers. Usually, the IOPAGE address range
is 4 kw which leaves 28kw for everything else, including RT-11
(assuming that is what you are running). There is one option
available with some hardware to reduce the address range
set aside for the IOPAGE to just 2kw which then leaves
30kw for everything else. Unless you are running a specific
program which requires the extra 2kw, it is probably not
worth the extra effort.
Jerome Fine