Sorry if this is a bit off topic, but I think there are SAM users who have experience with MGT's GDOS and G+DOS for ZX Spectrum.
I need to implement (in assembler) two file operations: - Read and overwrite any 1-KiB block of a file. - Read and write text lines sequentally. G+DOS does not provide hooks or routines for these operations, so they have to be implemented ad hoc. I know Andy Wright's Beta DOS included support for serial and random access files, but there's no disassembly available. I've searched the Microhobby magazine, which included many articles on GDOS and G+DOS, but there's nothing about this issue. I still have to finish searching the Format magazine. At the moment I'm studying the G+DOS disassembly, trying to identify the required low-level routines. I wonder if anybody has tinkered with this before and could help with an example code or any information. Thank you. -- Marcos Cruz http://programandala.net