What is computer hardware?
• Computer hardware are the physical components of the computer.
Input/Output Devices•Input/Output devices provide communication between user and hardware.– Input Devices• Keyboard• Mouse• Scanner
– Output Devices• Monitor• Speakers• Printer
Processors and Memory
• Central Processing Unit (CPU)– Performs basic functions, millions and billions of
times per second (brains of the computer)• Random-Access Memory – Stores data used by the CPU (before and after
processing)
Data Storage
• Data storage uses a variety of media. Capacity is measured in bits and bytes:– A bit represents the on or off state of a transistor
(symbolized by a 1 or a 0).– A byte is eight bits.– A kilobyte is 210 or 1,024 bytes.– A megabyte is 1,048,576 bytes.
Hard Drives
• The hard drive is the primary storage device in a computer. Hard drives are:– Long term, rewritable storage– Large capacity– Inexpensive– Fixed media (relatively difficult to move from one
computer to another)
Removable Media
• Some storage devices are more portable:– CD/DVD• Medium capacity• Inexpensive• Easy to transport from one computer to another
– Flash, Zip, USB drives• Differing capacities• Differing price per MB
Computer Software
• Software can be divided into two categories:– Systems software includes operating systems,
compilers, and utilities.– Application software runs on top of an operating
system.
What is an operating system?
• An operating system (OS) manages the hardware and software on a computer system. An OS:– Manages memory and hardware resources– Allocates resources to applications– Provides a consistent interface for applications
Operating Systems• UNIX/Linux
– Multiuser OS– Multitasking– Runs on many types of hardware– Modular tools
• Mac OS– First mainstream graphical user interface– Icons (pictures) and mouse replaced command line interface
• DOS/Windows– DOS gained popularity with first PCs– Windows provided graphical interface to DOS– Windows later separated itself from DOS underpinnings
Low-Level Languages
• Low-level programming languages use simple commands to communicate with the CPU:– Machine language (most basic language of the
CPU)– Assembly language (human readable, but close to
machine language)
High-Level Languages
• High-level languages can be procedural or object-oriented:– Procedural languages use a step-by-step process to solve a
problem.• Basic, Pascal, C
– Object-oriented languages model problems using objects that correspond to real-world counterparts.• Smalltalk, C++, Java