Save Protection For ADFS & DFS

By Ross Little

Originally published in EUG #22

Thanks to the article by Matthew Ford in EUG #21, all the bugs in my two Save Protection utilities have been found and rectified.

Since he comprehensively detailed the problems, it was possible to upgrade both of the programs, although I did feel that most people would not be able to do it themselves. Therefore I felt it right to submit the two upgraded programs, which can now be used problem-free, without much difficulty. For ease of use, as soon as the assembly language is in memory, the machine code is saved to disk, under the filename "SAFE" for both of the versions. The filenames of the source code are 'DFSsrc' and 'ADFSsrc' for the DFS and ADFS versions respectively.

Something to note is that whilst the DFS code was written with this filing system in mind, it was written more specifically to work on all formats. It could do this because it only used 'legal' OS calls, unlike the ADFS version. If you use either DFS, a non-Acorn filing system or an ADFS with PAGE at &E00, then the DFS version is for you. You'll know if you have PAGE as this memory address; as standard it comes at &1D00 but some people tell ADFS to use Sideways RAM for memory space. This frees extra memory and lowers PAGE.

As the title implies, I hope this is the last thing I have to do on Save Protection. As far as I know, the updated programs are 100% vermin free - if they aren't though, please tell me.

A Digression

Do you remember that old gem Game Show? Well, if you hadn't already noticed, it's not here this issue. Wanna know why? Tough. But last time there was a bug in the game Astermene. It's not serious, but it bothered me when I discovered it. When you go to the Escape menu and choose to sell your company, the text "REALLY SELL?" comes up, all over the top of the choices. All that needs to be done is a CLS command inserted in the relevant line. So, load in the game from EUG #21 and replace line 6400 with:

      6400 DEF PROCdouble:CLS

Please note that the space between the line number and the commands is for clarity only and should be omitted when the line is entered. The game should now be saved onto a different disk.

For now, that's all from me. Game Show will probably be back soon. See you late.

Ross Little, EUG #22