Serial lines and v6 ...

Bob Manners rjm at
Sat Dec 2 04:39:49 AEST 1995

Having given up trying to work out why v6 runs on my /34a, and v5
doesn't, I've turned my mind to the problem of trying to get a second
DL11 up and running so I can use a terminal as well as my trusty

I've set up a second DL11 on CSR address 176500, vector 300. This
device is set for 96008N1, for what it's worth, and works just fine
under RT11.

I rebuilt the v6 kernel to enable a second DL11 interface. I have no
guide to the source, so all this is based on my guesswork. Needless to
say, it doesn't work, and I'm now out of ideas:

Modified /usr/sys/dmr/kl.c, the KL/DL-11 driver source. I'm assured
that the KL11 is an ancient serial interface ...

Extract from said file ...

/* base address */
#define KLADDR 0177560 /* console */
#define KLBASE 0176500 /* kl and dl11-a */
#define DLBASE 0175610 /* dl-e */
#define NKL11 1
#define NDL11 0
#define DSRDY 02
#define RDRENB 01

I simply changed the number of KL11's from one to two:

#define NKL11 2

A further comment in the code says:

 * set up minor 0 to address KLADDR
 * set up minor 1 thru NKL11-1 to address from KLBASE
 * set up minor NKL11 on to addresss from DLBASE

What this is saying is that minor 0 will be 0177560 (my console, which
works fine), minor 1 will be 0176500 (which should be my second
DL11). The code even does what the comment says ... ;)

So I rebuild the kernel, reboot.

Now, /etc/mknod /dev/tty1 c 0 1

makes the device, and

echo Hi >/dev/tty1


/dev/tty1: cannot create

What is up? Naturally if I set up a login for that terminal by editing
/etc/ttys, the process loops and causes a great deal of disk
thrashing. Something is clearly up with the configuration of the
device drivers here ...

Does anyone know how I'm supposed to do this properly? Advice and
guidance would be much appreciated ...

On a completely different note, would someone be so kind as to give me
the source for a very small Bourne shell and accompanying utilities
(/bin/test etc...) that I could port to v6 without too much difficulty?




Robert Manners                                  Osney Laboratory
rjm at                          Dept of Engineering Science
                                                University of Oxford
                                                01865 288762
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       "Wall Street or Crack Dealer Avenue,
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