Comedi is described as 'collection of drivers for a variety of common data acquisition plug-in boards. The drivers are implemented as a core Linux kernel module providing common functionality and individual low-level driver modules'. There are three alternatives to Comedi for Windows, Linux, Mac, MS-DOS and BSD. The best alternative is LabVIEW. It's not free, so if you're looking for a free alternative, you could try MyOpenLab or Lawson Labs.
LabVIEW is a platform and development environment for graphical programming for measurement and automation. It is a development tool available for applications in test and measurement, data acquisition (DAQ), analysis, and instrument control (GPIB, VXI, and serial).
MyOpenLab is a platform for finished elements (program components) that can be linked together. You can also MyOpenLab with a house builder compare the building blocks used to build his house. The modules often create others.