[TUHS] running BSD 2.11 on my PDP 11/70 emulator

[Phil Budne]

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 at 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.