This is HAL targetted for the Interdata 70 mini.  The HAL code
cross-compiled on the PDP9/15 systems and wrote images to the
filestore which were then executed on the Interdatas, which
had no local storage. They were what is nowadays called 'bare
metal' systems which is why they were the host for our 4th-year
operating systems exercises!

We do have a working version of the 9/15 Imp compiler plus an
emulator, so we should be able to compile and run this HAL assembler.

There is a working pdp15 imp system at:
https://gtoal.com/history.dcs.ed.ac.uk/archive/languages/imp-pdp15
(or maybe https://gtoal.com/history.dcs.ed.ac.uk/archive/languages/imp15-tmp )
which should be able to compile and run hal70.

Unfortunately at the moment, we do not have any HAL code to feed
through it, but if we ever do recover the sources of systems such
as the Filestore, Legos, Isys, et al, we ought to be able to run
them under emulation.  I believe simh does support this processor.
Some of the scans in this directory may include the missing
software.

The Imp77 compiler appears to have been hosted on Isys (the big brother
to the 'bare metal' Interdata 70 systems) or possibly Legos (the big
sister of the bare Interdatas).  Passes 2 and 3 of that
compiler are here, and we separately have a project going to get
Imp77 running in several environments elsewhere - we *should* be
able to use pass1 from that project and the compiler itself to
get an Interdata cross-compiler running on x84 and possibly even
arm hardware.

The only component we seem to be short of in order to get a full
interdata emulation going is the departmental link and original
filestore, but writing a compatible equivalent *should* be less
than a week's work.  The protocol is well documented.

There are a lot of scans in this directory pending rotation to
a readable orientation! and conversion into readable pdf documents.

PS The "Basic" in this directory refers to the rather basic
environment of the small interdatas. It has no connection to
the BASIC programming language from Dartmouth.