prindle@NADC.ARPA (05/24/84)
It's hard to believe that anyone has not heard of this. Apparently, the bug in the 1541 DOS results when the allocated space becomes sufficiently fragmented and space for the replacement file must be gathered from a number of places on the disk; I suppose the BAM gets mis-interpreted and previously allocated blocks (part of other files) get re-used. The reason this is so terrible is that, first, it may cause no harm at all (especially on a relatively empty diskette), and second, when it does destroy, the file you are working with is just fine - it could be a long time before you try to use the damaged file(s); by that time you won't correlate the damage back to the save-with-replace! Much better you should save with a different name or, if you crave a little risk (someone shuts the power off in the middle of the save, etc.), you can: OPEN 15,8,15,"S:ZINGER":CLOSE 15:SAVE"ZINGER",8 In Simon's Basic, thats: DISK"S:ZINGER":SAVE"ZINGER",8 There have been rumors off and on over the last year that Commodore has fixed this bug, but with at least 3 different versions of 1541 out there, who can tell where or if it's been fixed. What is especially dangerous are programs (that you didn't write and never bothered to look at the listing) that do OPEN 1,8,2,"@DATAFILE,S,W" etc. from within the program. Frank Prindle Prindle@NADC