<P> Its subfields can be divided into practical techniques for its implementation and application in computer systems and purely theoretical areas . Some, such as computational complexity theory, which studies fundamental properties of computational problems, are highly abstract, while others, such as computer graphics, emphasize real - world applications . Still others focus on the challenges in implementing computations . For example, programming language theory studies approaches to description of computations, while the study of computer programming itself investigates various aspects of the use of programming languages and complex systems, and human--computer interaction focuses on the challenges in making computers and computations useful, usable, and universally accessible to humans . </P> <P> "Information systems (IS)" is the study of complementary networks of hardware and software (see information technology) that people and organizations use to collect, filter, process, create, and distribute data . Computing Careers says on their website that "A majority of IS programs are located in business schools; however, they may have different names such as management information systems, computer information systems, or business information systems . All IS degrees combine business and computing topics, but the emphasis between technical and organizational issues varies among programs . For example, programs differ substantially in the amount of programming required ." The study bridges business and computer science using the theoretical foundations of information and computation to study various business models and related algorithmic processes within a computer science discipline . Computer Information System (s) (CIS) is a field studying computers and algorithmic processes, including their principles, their software and hardware designs, their applications, and their impact on society while IS emphasizes functionality over design . </P> <P> Information technology (IT) is the application of computers and telecommunications equipment to store, retrieve, transmit and manipulate data, often in the context of a business or other enterprise . The term is commonly used as a synonym for computers and computer networks, but it also encompasses other information distribution technologies such as television and telephones . Several industries are associated with information technology, such as computer hardware, software, electronics, semiconductors, internet, telecom equipment, e-commerce and computer services . </P> <P> A system administrator, IT systems administrator, systems administrator, or sysadmin is a person employed to maintain and operate a computer system and / or network . The duties of a system administrator are wide - ranging, and vary widely from one organization to another . Sysadmins are usually charged with installing, supporting and maintaining servers or other computer systems, and planning for and responding to service outages and other problems . Other duties may include scripting or light programming, project management for systems - related projects, supervising or training computer operators, and being the consultant for computer problems beyond the knowledge of technical support staff . </P>

Which part of computer system analyses the program instructions and then issues control operations