||BBC BASIC for the PDP11
I started writing BBC BASIC for the PDP11 at university on the late 1980s. It
got as far as starting up, producing its startup message and prompting for
input. A few years ago I wrote a PDP
emulator and assembler and resumed work on
|PDP11 BBC BASIC running on|
PDP11 Unix Version 6 with an ASR33 Teletype
BBC BASIC uses standard PDP11 UNIX TRAPs for I/O (eg TRAP 4 for character
output and TRAP 3 for character input), so should run on any compliant
PDP11 UNIX. With a suitable HostIO source BBC BASIC will run on other
PDP11 systems. For example, TubeIO uses PDP11 Tube EMT calls for I/O and
RTIO uses RT-11 EMT calls - and will run on RSTS which has an RT-11 API
BBC BASIC v0.39 (21-Sep-2022):
Running BBC BASIC on Unix
Running BBC BASIC on a PDP11 Tube/CoPro
* bbcbasic for Bell Unix and BSD2.9 and earlier
* bsdbasic for BSD2.10 Unix and later
- Copy the file to an appropriate directory or into a Unix disk image with
a tool such as putr or
UxFiler with 'execute by all'
permissions (eg chmod 755), renaming bsdbasic to bbcbasic. On Unix a
suitable location is usually /usr/bin/bbcbasic.
- Alternatively, download the bbcpdp.zip archive
and extract it to your Unix system.
- Boot into into Unix, log on and type bbcbasic at the user
- bbcbasic is also directly runnable on
- Download basic.rom (13K, v0.29 21-Sep-2022).
- Load it into a bank of sideways RAM, or program it into an EPROM.
- With the PDP11 CoProcessor enabled, PDP11 BASIC will be the default
language and will be entered on Break or with *BASIC.
- Alternatively, the basic.rom file can be run from the PDP11>
- bbcpdp.ssd contains some demo programs, as well as a
copy of basic.rom.
- bbcbasic and basic.sav are also directly runnable on
Running BBC BASIC on RT11, RSTS and UKNC
- Download basic.sav and
copy the file to an appropriate RT-11 disk image with a tool such as
- Alternatively, download the bbcpdp.dsk disk image.
- Boot into into RT-11, select the disk with ASSIGN xyz: DK: where xyz:
is the disk with BBC BASIC on it.
- Type RUN BASIC (or RUN xyz:BASIC where
xyz: is the disk the BASIC.SAV file is on.
The source archive includes some demo programs and
Authored by J.G.Harston
Last update: 03-Sep-2022