This is an updated version of TBUG V1.1, the 3L transputer debugger, which
works on modern 32/64-bit Windows systems instead of the original 16-bit
DOS/Windows version.  The files here _must_ be installed into a directory
called \TBUG (Tbug looks for and creates some files there at run time.)
This directory should be added to the _start_ rather than the end of your
PATH (see later for the reason why.)

The following files have been updated from the original:

      TBUG.B4    Uses ANSI escape sequences to write to the Windows terminal
                 rather than writing directly to a VGA hardware display
                 buffer as in the original, plus other similar changes.
      TBUG.EXE   Variant of the 2013 DRIVER.EXE, which, as well as running
                 on 32/64-bit systems, finds out the size of the terminal
                 screen in rows and columns and passes this into TBUG.B4 via
                 a new /S command-line switch.

The following have been removed:

      AFSERVER.EXE  A copy of Gavin Crate's JAFSERVER.EXE transputer
                    emulator for the PC must be present on the PATH instead.
      NECSERVE.EXE  The NEC PC is no longer supported.
      WINEDIT.*     The WINEDIT command is not supported.

Both this version and the original Tbug scan the Windows PATH for files
(BASEFILE.PDM, TBUG.PDM).  The limitation of the AFSERVER.C code built into
JAFSERVER.EXE to 64-character filenames means that many modern PATH
setups will cause problems for Tbug, which may cause it to fail.  The
effect can be minimised by putting \TBUG at the _beginning_ of the PATH
rather than, as is more usual, adding it to the end.

Note that, although you can invoke TBUG with no command-line arguments
and this will bring up a file-selection interface as in the original
version, moving around the directory tree in the interface will _not_
change the working directory, unlike in the original version.  This may
mean that after you select a .B4 file to debug, Tbug won't be able to
find the source code.  In general, it will probably be best to invoke
Tbug with the current working directory already set to the directory
containing the .B4 file and the source code you want to debug.

Fiona Culloch,
May 2026
