A Windows Service is a running (or potentially runnable) background program in the Windows operating system. So various server-software are implemented as one or more services with not direct user-interface from the service itself.
QV Services are the various services that are together giving the running QlikView server environment:
QVS - QlikView Server is the part that runs all the active QlikView applications and handle multiple users and what must be handled during the running of the program: selections for each user, intermediate results, all calculations and the in-memory database of each application, caching of all the cacheable objects etc etc.
QDS - QlikView Distribution Service - the part that runs load scripts according to the plans set up via the QlikView Managment Console (QMC)
QMC - QlikView Managment Console - the user-interface to the QlikView Mangement Service QMS that records various configuration options for the entire QlikView server environement making it possible to work as a whole. In addition the scheduling of various reloads named tasks are done here.
QVws - QlikView Webserver - or most often referred to as AccessPoint - gives the web-user interface of the QlikView server environement for browsers (Ajax client) and iOS-client.
DSC - Directory Service Connector - the program/service that interacts with various directory services - more often than not this is just Active Directory for most QlikView installations.
QVS interacts with QVws all the time when browsers are running a QlikView applications. They cooperate to deliver the entire application - User-Interface and Data and all the interactive functionality.
QVS interacts with DSC.
QDS - interacts mostly with just QMS - QMS being the master that triggers various reload tasks (definition of a reload of a particular document triggered by various events like date, time, external events or dependencies).
QMS (visible via the user-interface of QMC) is interactive with all services so it can be interrogated, monitored and configured.
