This is a testing distribution of 2.11BSD for the PiDP-11. There is a drop-in
replacement disk image for the BSD system included in Oscar Vermeulen’s
systems.tar.gz. The source code for the programs here, including httpd,
are also included in the disk image under /home/user/src/.
I try to keep this distribution up to date with the latest patches, which are available at ftp://ftp.update.uu.se/pub/pdp11/2.11BSD/Patches/
- For more information on the PiDP-11, see: https://obsolescence.wixsite.com/obsolescence/pidp-11
- For more useful tools and guides for 2.11BSD: https://github.com/rricharz/pidp11-2.11bsd
Please refer to the excellent PiDP-11 manual, especially the section titled “A Quick Tour of 2.11BSD”, to get the system set up:
If you’re using the PiDP-11 distribution, unpack 2.11BSD_rq.dsk.xz with
unxz and put the disk image in /opt/pidp11/systems/211bsd/. Boot BSD in
the normal way (i.e., set the panel switches to 0102 octal and press the
address rotary switch to reboot the emulator). Press enter at the boot
prompt.
The system now starts in multi-user mode by default. Johnny Billquist’s patch
456 implemented a “clean” flag in the filesystem, which allows fsck to skip
the boot-time check if the system was previously shut down cleanly. This cuts
a lot of time off the boot sequence and makes it more practical to boot
directly into multi-user mode.
Since this is the first boot and you have not yet configured networking on the system, it will appear to hang for a few minutes as the services try to use the network. See below for instructions on configuring networking.
If you want to boot into single-user mode, see the section at the end of this document.
You can log in as root, user, and tektronix with no password. It’s a good
idea to set passwords for these accounts using passwd, especially if you plan
to connect the system to a network. A lot of network services are enabled by
default, including ftp, telnet, rsh, and rlogin.
Optionally, you can change the name of user to your preferred user name. Use
vipw to edit the passwd file (/etc/master.passwd). Don’t forget to move the
home directory if you change it in the passwd file. You can also add your user
name to the wheel group in /etc/group, which will allow you to su to
root while logged in as your user.
You will need to edit /etc/hosts, /etc/netstart, and /etc/resolv.conf
with the correct IP addresses. You can also change the hostname if you want.
If you’re a vi user, this is a great opportunity to use the original BSD vi.
It’s not as fancy as vim but it works fine. If you like emacs, jove is an
emacs clone that comes installed.
Log in as user tektronix. The directories under /home/tektronix/ contain
example programs and plot files for use with Rene Richarz’ Tektronix 4010
graphics terminal emulator.
See the following pages for instructions:
- https://github.com/rricharz/pidp11-2.11bsd/blob/master/Tek.pdf
- https://github.com/rricharz/pidp11-2.11bsd/blob/master/Tek.odt
Tek4010 terminal emulator for Linux/X:
Aaron Jackson wrote a simple web server, which I added a few features to,
including logging and basic CGI support. It’s running by default; once you have
networking set up, point a web browser to your 2.11BSD IP address and you
should see a default index.html. The document root is /home/www/. More
documentation and the source code are available in /home/user/src/httpd/.
There is an example CGI program in /home/user/src/weather/. It prints the
output of two commands, welcome_html and weather. weather itself relies
on read_sensors, which reads temperature and pressure sensor data from
a memory-mapped sensor device; see
https://obsolescence.wixsite.com/obsolescence/pidp-11-temp-barometer-hack
for further information. Source for all these programs is also included in
/home/user/src/.
You can see the web server with CGI in action (assuming my PiDP-11 is up) at http://chasecovello.ddns.net/.
You can set up a print server on Raspbian (or anywhere else, really), and then
configure 2.11BSD lpd to send print jobs to the remote lpd server.
First, here’s what you need to do to set up the cups-lpd server on the host:
Install cups (and optionally the graphical configuration utility) on Raspbian:
sudo apt install cups system-config-printer
Create /lib/systemd/system/cups-lpd.socket with the following:
[Unit] Description=CUPS LPD Server Socket PartOf=cups-lpd.service [Socket] ListenStream=515 Accept=true [Install] WantedBy=sockets.target
Create /lib/systemd/system/cups-lpd@.service with the following:
[Unit] Description=CUPS LPD server Documentation=man:cups-lpd(8) [Service] ExecStart=/usr/lib/cups/daemon/cups-lpd -n -o job-sheets=none,none -o document-format=application/octet-stream StandardInput=socket [Install] WantedBy=multi-user.target
Enable cups-lpd:
sudo systemctl enable cups-lpd.socket sudo systemctl start cups-lpd.socket
Then use the printer setup tool to set up your printer, make sure it’s set as
shared, and take note of the name of the printer assigned by CUPS; you will
be adding it to the printcap file on BSD.
cups-lpd doesn’t appear to do any authentication, so it’s probably also a
good idea to set up a firewall to only accept incoming connections to port
515/tcp from your 2.11BSD IP.
Finally, return to 2.11BSD and make sure you’ve set up networking above. lpd
expects to connect to a print server host called ‘rpi’, and /etc/hosts
should point to its IP. You will also need to edit the name of the CUPS
printer in /etc/printcap.
After that, you can try printing a file:
man printcap | lpr
If you want to boot into single-user mode (to perform system maintenance, or to have the maximum amount of memory available for, say, a kernel recompile), press a key at the bootloader prompt, then type:
unix -s
If you do this, it’s still a good idea to check the filesystems before doing anything else:
fsck -p -t scratch
As noted above, this will be fast if the system was shut down cleanly last time. If not, it may take 10 minutes or so (on a Raspberry Pi 3B+). It’s worth the time – not checking a dirty filesystem is a good way to end up with filesystem corruption.
If you’re in single-user mode, the terminal isn’t yet set up correctly, so
vi won’t work. If you don’t want to be stuck with ed, you can set up the
terminal manually:
TERM=vt100 export TERM stty rows 24
(Replace 24 with the number of rows in your terminal)
Press Ctrl-D to bring up multi-user mode and start networking and default
system services.
Traditionally, 2.11BSD booted into single-user mode, where the administrator could perform manual system maintenance before bringing the system up in multi-user mode. See
- https://github.com/rricharz/pidp11-2.11bsd/blob/master/Maintenance.pdf
- https://github.com/rricharz/pidp11-2.11bsd/blob/master/Maintenance.odt
for a quick overview of Unix system maintenance tasks.
The 2.11BSD bootloader was recently updated to allow booting directly into multi-user mode, and this has been enabled by default. However, if you want to have an installation that’s both less convenient and less anachronistic, you can rebuild the bootloader to bring back the old behavior.
This is also a great introduction to the /usr/src/ tree, and how easy it is
to rebuild the entire system from the included source. Here’s how to do it
(instructions adapted from Johnny Billquist’s original):
- cd to
/usr/src/sys/pdpstand/ - Edit
boot.c. Look for a line that says:
#define AUTOMULTIUSER 1 /* 0 = old behaviour, !0 = new (automatic) behaviour */
- Change the define to a 0.
make install- Reboot.
- Copy PIDP11 to a new config filename in
/usr/src/sys/conf/ ./config NEWCONFIGNAMEcd /usr/src/sys/NEWCONFIGNAME ; make
If you get a ld: too big for type 431 error while building a new kernel,
you will need to move object files into different overlays in the Makefile.
http://www.dnull.com/bsd/oldnews/bsdnew62161.html fully explains why this
is so and how to make the modifications, but tl;dr:
size unix.o. If any overlay is bigger than 8192, move one of the OV1
through OV9 .o files into a smaller overlay. If text is bigger than
57344, move one of the BASE .o files into an overlay. Run make and size
unix.o until you have the base and overlay size situation rebalanced. Then
proceed with make install.
The kernel used for this distribution is PIDP11. For that kernel both
BASE and OV6 are too big; moving lp.o from BASE to OV5 and
init_main.o from OV6 to OV5 will allow it to build successfully.