MANUAL FOR RFSHEAD (BBC BASIC & 6502 ASSEMBLER)

This file describes the program RFSHEAD which automatically generates a ROM
image laid out in the format that the ROM filing system understands. The ROM 
filing system is supplied as standard since OS 1.00, and is selected with *ROM.
The manual is (C)1998 SPROW and software is (C)1997 SPROW

INSTRUCTIONS-
At the BASIC prompt, type CHAIN"RFSHEAD"

You'll next need to enter the maximum size of the ROM you have available. 
This is normally either 16k (&4000) or 8k (&2000), which should be entered 
when prompted.

The next selection is whether the resulting image will be used as a sideways
ROM programmed into EPROM or as a speech system ROM programmed into a serial
PHROM such as a TMS6100. Use the space bar to toggle between the options, and
return to select.

At the '(C)' prompt, enter the copyright message which is to be put in ROM. It
should be in the form "(C)YYYY Author" for consistency with other ROMs.

Lastly, the date should be entered in the DDMMYY form, this will then be used 
to generate a semi unique number. This is to aid easy tracking of ROM revisions 
and will appear in response to *HELP in the resulting ROM, and becomes the
serial number for speech system ROMs.

If you are producing a sideways ROM image you should now enter a block of help
text, this might simply be a list of the files which will appear on the ROM, 
or might be an example of their usage. Or it could be a plain text description
of what your ROM does. This will only be displayed in response to *HELP RFS, 
and does not require the ROM filing system to be selected.

The ROM header will be made, then you can continually enter as many filenames
as the chip has space for. Each may optionally be called something else when in
ROM (remember - the ROM filing system can have 10 letter filenames) and locked 
if required.

Locking means that in future your program can only be *RUN so that other users
cannot load then reverse engineer your software.

This process continues until you run out of space on the chip, or you enter a
blank filename. Then the final image is saved to 'OUTPUT' ready for
programming.

KNOWN PROBLEMS/FUTURE ENHANCEMENTS-
No known problems
Could be adapted to create images that span more than one physical ROM so that
the maximum filesize is only constrained by the number of free sockets in the 
machine.

HISTORY-
V1.00 First edition, used to hold my EPROM programmer software
V1.05 Improved the ROM filing system service call handler so it doesn't need
      use of any vectors.
V1.06 Shuffled code around to eliminate GOTOs, removed a spurious CLOSE#0.  
V1.16 Merged functionality of MkRFSPhrom which created speech system ROM
      images from a raw RFS image.
      Improved the accuracy of the free space calculation by taking into 
      account the space used by the header rather than calculating from the
      start of the whole image. Blank the unused ROM space with &FF.
      The empty help text case now doesn't leave a CR as the help text.
      Squeezed the entered date into a 16 bit id so it can also be used as the
      two byte serial number in speech system ROMs. Increased the DIM to hold 
      the name from 16 to 128 bytes to match the unzip utility. 

DISTRIBUTION-
The assembler which interfaces with the operating system is (C)1997 SPROW and
must not be altered without the author's permission. You are however free
to distribute the resulting ROMs with no royalty payments, provided the above
condition is met.