8 Apr
2025
8 Apr
'25
6:42 p.m.
A fun thing 2.11BSD does is it runs networking in supervisor code
in supervisor mode so that mbufs don't need to appear in the kernel
address space. It was the first thing that came to my mind when
you mentioned having trouble.
This is what I see booting 2.11 under SimH:
44Boot from ra(0,0,0) at 0172150
: unix
Boot: bootdev=02400 bootcsr=0172150
2.11 BSD UNIX #19: Sun Jun 17 16:44:43 PDT 2012
root@pdp11:/usr/src/sys/ZEKE
ra0: Ver 3 mod 3
ra0: RA82 size=1954000
attaching de0 csr 174510
attaching lo0
phys mem = 3932160
avail mem = 3553344
user mem = 307200
May 26 12:08:51 init: configure system
dz 0 csr 160100 vector 310 attached
ra 0 csr 172150 vector 154 vectorset attached
erase, kill ^U, intr ^C
#
A quick look at the code (the best documentation):
"user mem" output is the result of:
printf("user mem = %D\n", ctob((long)MAXMEM));
in init_main.c
MAXMEM is defined in param.h:
/*
* MAXMEM is the maximum core per process is allowed. First number is Kb.
*/
#define MAXMEM (300*16)
So the number being output seems like the intended value.