We have used several programming languages over the years. In reverse chronological order:

C++

C

Visual Basic

Ada

Pascal

Applesoft Basic

Fortran 77

Fortran NF (no Format)

Fortran IV

Fortran II

We have used numerous operating systems, including:

Linux (several kernels)

Solaris

Microsoft Windows (3.1 to current)

MS DOS

USCD p-system

CPM

Apple DOS

Unix

There have been others that we have tried along the years, but have not used for any length of time.