On 11/28/2013 04:11, Buchbinder, Barry (NIH/NIAID) [E] wrote: > Technically, the following is off topic for this list. But because > it is about what appears to me as a done deal - something that is too > late to change - I thought it might be off-topic for the main list. > We can move it there if you feel that appropriate. > > As I understand it, 32 bit and 64 bit have to be in different directory > trees, e.g., C:\cygwin and C:\cygwin64. As I understand it, that > is because they both look for /bin/cygwin1.dll and avoid getting the > wrong one by having different root directories. > Windows will spick the correct bitness if you have both in PATH. This is not the case if you somehow managed to install 64bit Cygwin on 32bit Windows, in which case you deserve the error :) > My question is why 64 bit wasn't named cygwin2.dll? 32 bit would > be version 1.7.25 and the corresponding 64 bit version would be > 2.7.25. Could that have allowed a single, mixed, transitional, > 64-except-32-when-no-64 installation? > Why? It is built from exactly the same sources, it is also the first version on 64bit Windows. Not to mention many programs hardcoded to load "cygwin1.dll" dynamically.