dillon@ucbvax.ARPA (The Sherif "Matt D.") (01/12/85)
There does exist an @replace bug, But it's very obscure. It is not caused by illigal scratching or uninitialized disks, as it used to happen to me before I stopped using it. Of course many terrible things happen due to other errors. A word of warning... If you plan to use ROM routines in the 1541 BEWARE Considering that there are already 5 ROM generations of the 1541, and probably will be more, The addresses you use inside the 1541 will change. You cannot realisticly expect your program to work on other C64's with 1541's. The only thing you really can rely on in terms of the 1541 is the I/O. A program to read data from a track which does not use any ROM routines works on ALL generations, as well as the 2031. But, you must remember several things when reading raw data directly from the disk: The data is encoded... You have to decode it as well as worry about sync marks. The data density changes depending on the track your on Unless your a hacker, and already have delved into the 1541's ROMS, your never going to understand the technical aspects of the 1541. The best sector transfer rate I've been able to get from the 2031, and the best sector transfer rate Bryce has been able to get from the 1541 using his FLASH! has been a skew factor of 4 ... About a track a second in terms of program loading time. This was accomplished by downloading a 3-page program to THe 2031 (1541) which did everything manually and did not touch ROM routines, which then transfered the data non-standardly to the host computer (PET/64). Matt.