The paper shows that analytical comparison of the web-scale open and free source discovery software in libraries and other museums, along with the different discovery services, is available both in commercial and open-source domains. The paper discusses several open-source discovery software tools and identifies discovery layers in the open-source domain, based on which can be compared to compare the usability and accessibility of different discovery layers of all usable software. It will identify tools potential of applications of these interactive, combined, and participative tools in enhancing existing library services and the viability of introducing next-generation library services. Therefore, today all world looks over the newly made association, which is the library discovery systems software. Discovery layers in the open-source domain make an analytical evaluation in the environment of the resource of digital library software distributed across the globe.