MEMO

To:       J.B.Tansley
From:     Graham Toal
CC:       Interested parties

Subject:  BBC Micro software standards.

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   Sir,
      I would like to bring to your attention a growing problem
   in the field of software for the BBC Micro.  For two years
   now, myself and others like me have been implementing systems
   for the BBC machine which have been committed to ROM and
   distributed at large.  One of the main problems we face is that
   of compatibility between roms. Often you find that one ROM will
   not function correctly when another is in the same machine.

      When outside companies sell software that does not work
   with our own software, we blame them for 'not following the
   Acorn software standards'.  When we ourselves write software
   which is not compatible with other programs, we say that it
   might be different, but it does adhere to the spec...
   (This is known as 'don't fix it, document it.)

      There exist several documents within Acorn describing the
   protocols to be used for various types of software, e.g.
   'Languages', 'filing systems' & 'service roms'.  I know for
   a fact that these documents have to date been deficient in
   the precision in which the specify interfaces and actions.

      I personally have found that the only document which comes
   close to reflecting reality is the 'Advanced User Guide' which
   is 'unofficial' (to use a favourite Acorn word) and incomplete.

      We are coming into an age where more and more software is
   available in ROM and therefor more and more combinations are
   likely in which interface problems can arise.



      We cannot blame our suppliers (OR our own programmers) for
   failure to comply with a 'standard' which is not cast in stone
   to an unambiguous degree.

      Specific examples of problem areas are:
      1) status bits on return from filing system operations
      2) slightly different semantics for the similar calls
         on different filing systems
      3) Use of workspace for permanently resident (and active)
         utilities which are not classed as 'filing systems'
      4) multiple intercepting & excision of vectors
      5) code-area for RAM-based utilities (e.g. network utils)
      6) workspace for IO-processor utilities when 2nd proc. fitted
      7) naming conventions for utility rom commands

      The answers to most questions are written down somewhere,
   but seldom precisely and never in the one place.  Usually,
   facts are passed on by asking the authors of whatever code
   you are interested in.  This was quite acceptable in a small
   company, but is becoming more difficult as Acorn grows and
   staff become distributed.  Also, new members of staff do not
   often realise that a problem exists and so do not ask for help.

      This memo is a request to see a definitive Acorn software
   document which company employees and external people alike
   can use to write software which, barring incompetance, will
   put an end to the headaches caused by incompatible notions
   of what an interface defines.

Graham Toal.