Computers started out as massive mainframes that could fill an entire room. Then, micro-technology led to the computer shrinking down to such a size that it could fit in an individual's palm. However, businesses are realizing that contemporary mainframe computers have a number of useful functions.
Central Data Repository
Unlike modern personal computers in which every workstation has a hard drive of its own, mainframe computers store every user's data within itself. This takes the form of the application binary data to execute programs, as well as the configuration and data files for every user. When users log in from a remote terminal, the mainframe gives that terminal access to the files and programs that the user has the authorization to access or execute.
Preserve Data Permissions
Storing applications and data on a single mainframe can lead to increased productivity and efficiency, as administrators can simply load data files or applications into the mainframe and then set which users can access them. While this system has its advantages, the system running on the mainframe must preserve and enforce user privileges to ensure that only authorized users can access specified applications or data files. A malfunction or glitch in such enforcement could have serious security implications for the firm using the mainframe.
Allocate Processor Time
Unlike personal computers which give every workstation a processor that is dedicated to crunching numbers for its user's computer use, mainframes have a limited number of processing cores to divide among users that are currently logged in. The mainframe can do this in a variety of ways, such as different users having different priorities attached to their accounts, or the mainframe attaching different priorities to different types of processes or programs. The mainframe's system administrator can choose how to allocate processor time.
Run Intensive Applications
The primary benefit of running a mainframe is its sheer processing power. In 2011, a mainframe could have 16 or more processor cores. This makes them ideal for running programs that require huge amounts of computational resources. Such programs can include financial trading systems or programs that model massively complex social or scientific systems. Using a mainframe to run these programs not only increases the speed at which they operate, but cuts down on the overall level of hardware that the programs would require in the first place.