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Computing Basics. Chapter 3, Exploring the Digital Domain. Computing Basics. how computers process information how hardware is organized for instruction-execution how software directs processing the role of the operating system how the OS manages files, user interface
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Computing Basics Chapter 3, Exploring the Digital Domain
Computing Basics • how computers process information • how hardware is organized for instruction-execution • how software directs processing • the role of the operating system • how the OS manages files, user interface • common features of application software In this chapter you will learn about . . .
Computer System • a computer system is an electronic digital data processing machine • data -- symbolic representation of information • a computer process is sequence of states during which data is modified in specific ways • a program is a sequence of instructions that direct a process
Instruction-Execution Cycle • fetching the next instruction • decoding (or interpreting) that instruction • executing what the instruction prescribes
Computer System • HARDWARE • devices, equipment • SOFTWARE • programs
Processor System stores both data and instructions used for processing interconnections manages the instruction-execution cycle
Memory • information (data) is stored in uniform-sized units • each unit has a unique address • reading from memory • copy data from a memory location • writing to memory • moving data into a memory location
Secondary Memory and I/O • Secondary memory • nonvolatile storage • cheaper, mass storage • Input/Output devices • input--translates human-readable forms of information to machine-readable data • output-- translates machine-readable data to human-readable forms
Software • programs • written using programming languages (symbolic codes for expressing computer instructions) • programs ≠ processes • conditional processing • the ability to alternative actions based on the recognition of changing conditions
Operating Systems • continuous control of system • supervises processes • creates useful abstractions for users • defines computing experience An operating system is a collection of resident programs that manage the computer’s resources, supervise the execution of processes, and provides useful services and security.
Managing Files • A file is a sequence of items treated as a unit and identified with a unique name • filenames are composed of • identifier + ‘ .’ + extension • identifier (Windows) = up to 255 symbols excluding special characters • extension (Windows) = 1 - 4 characters that are used to classify file
tree--special type of graph nodes, edges (links) parent(s) child(ren) ancestor(s) descendant(s) directory structure--series of levels based on a tree files, folders path--list of all ancestors of a file/folder from root pathname--conventional listing of path Hierarchical File System
TEXT-BASED command line interpreters terse, but powerful steeper learning curves burden of communication on user GRAPHIC USER INTERFACES (GUI) manipulate visual elements user-friendly more tedious User Interface
Applications • are restricted to a specific problem domain • have a user interface based on some intuitive metaphor • use conducted in sessions