Hi!pjw wrote: Tue May 27, 2025 10:33 am Im sorry my manuals are so obtuse! I will try harder to make them clearer.
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Thank you very much for such detailed answer

Your manual is not obtuse, it is my mind some days


Again, thank you

Hi!pjw wrote: Tue May 27, 2025 10:33 am Im sorry my manuals are so obtuse! I will try harder to make them clearer.
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Hi Derek,Derek_Stewart wrote: Wed May 28, 2025 7:32 am When there is no microdrive cartridge in the the drive, there should be a system error generated: ERR_NF (-7) file or device not found. See QDOS Technical Manual Chapter 18.1 Page 158 and SMSQ/E calls the error code: err.fdnf (-7) file or device not found, see SMSQDOS Reference Manual section 18.1
The error can be caught using a WHEN ERRor clause, see QL User manual or online Superbasic manual for details and Toolkit 2 and Qliberator manuals for updates.
Note pre-JS Roms the WHEN ERRor did not work, so, JS, Minerva, SMSQ/E are the only versions that will work.
Have a look at DIY Toolkit's graphics functions. They provide pixel coordinate plot and draw functions in assembly language.
I had intended to convert the plotline algorithm to assembler, but then I got stuck on the high colour modes and the whole project became too complicated for what was intended as a leisurely walk in the park.