Cygwin is way older than CoLinux. CoLinux is from 2004. Cygwin was first released in 1995.
The problem with Cygwin as I remember it was DLL hell. You'd have applications (such as a OpenSSH port for Windows) which would include their own cygwin1.dll and then you'd have issues with different versions of said DLL.
Cygwin had less overhead which mattered in a world of limited RAM and heavy, limited swapping (x86-32, limited I/O, PATA, ...).
Those constraints also meant native applications instead of Web 2.0 NodeJS and what not. Java specifically had a bad name, and back then not even a coherent UI toolkit.
The problem with Cygwin as I remember it was DLL hell. You'd have applications (such as a OpenSSH port for Windows) which would include their own cygwin1.dll and then you'd have issues with different versions of said DLL.
Cygwin had less overhead which mattered in a world of limited RAM and heavy, limited swapping (x86-32, limited I/O, PATA, ...).
Those constraints also meant native applications instead of Web 2.0 NodeJS and what not. Java specifically had a bad name, and back then not even a coherent UI toolkit.
As always: two steps forward, one step back.