I am still trying to convert .tap and .prg to real cassette files. I have built the required cassette interface and I am using software called 'cbmtt101' in DOS to record tape images. So far, the best I have acheived is getting most of a 8k program into a PET. The software asks me for a start address and I really don't know what this should be, so I just go with the default. Does anyone have any knowledge of this means of transfering tapes between pc and Pet/VIC/64? What is a PET/64/plus4 start address?
Commodore program files have a 2-byte header which indicates the (start) address the file was saved from. For C64 this is usually $801 (2049). For C128 this is usually either $1c01 or $4001. Other machines I am not so sure about. I think for PET it is $401 (1025), and for Plus/4 it is $1001 (4097). The VIC is crazy! It depends on type/amount of expansion RAM...
One nice thing, if the program is BASIC (not machine language) then it shouldn't matter :) Most Commodore machines (VIC/C64/Plus4/C128) will load to a standard location (ignore load address of file) and make any corrections needed after loading. The PET probably does this too, but I'm not sure...