| A | B |
|---|
| ENIAC | one of the world's first computers |
| hardware | physical devices that you see connected on your desktop |
| software | the programs that give the hardware useful functionality |
| bit | the smallest unit of information processed by a computer and consists of a siingle 0 or 1 |
| binary digit | bit |
| byte | eight adjacent bits |
| a PC's 6 major subsystems | CPU, RAM, Auxiliary I/O devices, Auxiliary Storage Devices, User Interface, Network Connection |
| user interface devices | keyboard, mouse, monitor, speakers etc. |
| I/O | input/output |
| auxiliary I/O devices | scanners, joysticks, keypads etc |
| secondary memory | auxiliary storage |
| auxiliary storage | the devices that store the computer's operating system, applications, document and files we write |
| hard disks | usually internal to the pc storing gigabytes(presently) of information |
| portable storage mediums | CD-ROMs, DVDs, Zip disks, floppy disks |
| storage capacity of CD-ROMs | 640 MB |
| storage capacity of DVDs | 6400 MB |
| storage capacity of Zip diks | 100 - 200 MB |
| storage capacity of 2.25 " floppy disks | 1.4 MB |
| network connections | connects us to the internet and/or other computers |
| The two kinds of internal memory | RAM and ROM |
| primary memory | RAM |
| RAM | random access memory |
| ROM | read-only memory |
| read-only memory | reserved for critical system programs that are used when a program starts up |
| random access memory | high-speed internal memory holding most of the programs running at any one time and lost every time the computer shuts down |
| CPU | central processing unit |
| central processing unit | does the work of the PC - arithmetic operations, comparison operations, some I/O operations |
| Moore's Law | engineers have been doubling the speed of CPUs about every 18 months |
| transistor | the basic building block of CPUs and RAM consisting of 2 states ON/OFF - patterns of 1s and 0s |
| system software | supports the basic operations of a computer and allows human users to transfer information to and from the computer |
| applicaton software | allows human users to accomplish specialized tasks including word processors, spreadsheets, database systems, graphical software etc |
| binary | base 2 |
| octal | base 8 |
| hexadecimal | base 16 |
| floating-point numbers | numbers with a fractional part |
| mantissa/exponent notation | the number is written as a value between 0 and 1 times a power of 10 |
| ASCII | American Standard of Information Interchange |
| ASCII is used to: | a pattern of 8 bits used to represent characters, numbers and symbols |
| Unicode | a pattern of 16 bits used to represent characters, numbers and symbols |
| strings | sequences of characters (like words or sentences) |
| pixel | a grid cell of an image |
| sound | every 1/44,000 of a second amplitude is converted to binary |
| program instructions | a sequence of bits |
| address | the location of a byte in memory |
| ACM | the Association for Computing Machinery |
| Generation 1 programming languages | machine languages (1940-1950) |
| Generation 2 programming languages | assembly languages (1950 to present) |
| Generation 3 programming languages | high-level languages (mid 1950 to present) |
| machine languages | toggled switches to enter 0s and 1s as programs into RAM |
| assembly language | each instruction conforms to one machine language instruction |
| assembler | a program that translates an assembly language program into machine language |
| loader | runs the machine language program |
| high-level languages | FORTRAN, COBOL, BASIC, C, Pascal, C++, Java, etc |
| compiler | translates high-level languages to machine language |
| SDLC | software development life cycle |
| SDLC waterfall model steps | Customer request (user requirements phase), analysis, implementation, integration, maintenance |
| procedural approach | older approach to programming - sequencial steps and procedures used |
| object-oriented approach | newer language approach - object based |
| OOP | object-oriented programming |
| programming | the process of creating computer software |
| methods | rules of behavior |
| instance variables | a list of data resources |
| encapsulation | combining the description of resources and behaviors into a single software entity |
| classes | different types of software components in a program |
| information hiding | principle of providing access to services but not to data resources |
