It's a clever way of storing the 2 extra bytes in the Acorn filename in the main part of a DOS filename, but unfortunately it makes the names look like junk, and it's not always possible to access them. I've never been able to access on DOS Plus that file I created "DRIVEDFILE", which shows as "D<IV%D&)". It isn't infallible, as it doesn't cope with file where the last 2 letters are outside the ASCII range A-P. Also there's a gap in the implementation if both final characters happen to be A, because deducting the base value for that results in 0, meaning no change is made to the DOS Plus filename, so "AAAAAAAAAA" displays as "AAAAAAAA" which might also be an existing file.
And, as I found out, it only does this encoding for 10 character filenames. 9 character names are not altered, and display as "ABCDEFGH I" with a separator before the final character which in the DOS directory display separates the "8" from the "+3" element. Given that 11 characters altogether can be used in DOS filenames, I really don't know why they didn't just encode any Acorn name longer than 8 characters as "ABCDEFGH.IJ" !
And, as I found out, it only does this encoding for 10 character filenames. 9 character names are not altered, and display as "ABCDEFGH I" with a separator before the final character which in the DOS directory display separates the "8" from the "+3" element. Given that 11 characters altogether can be used in DOS filenames, I really don't know why they didn't just encode any Acorn name longer than 8 characters as "ABCDEFGH.IJ" !
Statistics: Posted by BeebMaster — Mon Nov 18, 2024 12:25 pm