Hi
Can somebody explain the apparently minor differences between 80 and O files and 81 and P files.
I can't find this information anywhere and it definitely needs writing up somewhere.
Regards,
Thunor
80 file format, 81 file format
Re: 80 file format, 81 file format
AFAIK, both file formats consist of the raw byte stream as written on tape. So the differences should be the same as for the tape format:
- ZX81 files start with the file name, ZX80 files do not have a name included and just start with the data
- The memory offset for ZX81 files is 4009 hex, whereas the offset for ZX80 files is 400A hex
- The system variables that are always written with the files are different on both computer, therefore also the stored files
Here is a small software tool that I use to convert .O and .P files into .wav sound files so I can load them using the soundcard of my PC. It autodetects the file type.
Greetings
Oliver
- ZX81 files start with the file name, ZX80 files do not have a name included and just start with the data
- The memory offset for ZX81 files is 4009 hex, whereas the offset for ZX80 files is 400A hex
- The system variables that are always written with the files are different on both computer, therefore also the stored files
Here is a small software tool that I use to convert .O and .P files into .wav sound files so I can load them using the soundcard of my PC. It autodetects the file type.
Greetings
Oliver
Re: 80 file format, 81 file format
I've found this not to be entirely accurate; of the files I have the .p/.81 files appear to be the data that would appear on a tape, with the filename missing. So, on a real ZX81 tape you'd see:
As stated above, ZX80 tape images appear to be a complete duplication of the data on a ZX80 tape. The ZX80 doesn't store filenames at all.
- long pause
- filename, with the high bit set on the final character
- file data
- short pause
- file data
As stated above, ZX80 tape images appear to be a complete duplication of the data on a ZX80 tape. The ZX80 doesn't store filenames at all.
Re: 80 file format, 81 file format
The ZX81 saves system variables from 0x4009 onward. The ZX80 saves all system variables from 0x4000 onward.
C
C