Cs 115 Bab 1

Front 1

computer science includes

Back 1

mathematics-formal notations, logic
engineers-building systems, designing
scientists-observe, make hypothesis, test

Front 2

computer scientist must be good in problem solving

Back 2

state problem clearly
think of solutions (including thinking out of box)
state solution clearly

Front 3

what is algorithm?

Back 3

step by step list of instruction to solve a problem

Front 4

one example of algorithm

Back 4

Euclid's algorithm for GCD

Front 5

primary memory (RAM)

Back 5

volatile(lost contents if power interrupted)
fast(nanoseconds)
expensive(per MB or GB)

Front 6

secondary storage (HD, CD, DVD, memory stick)

Back 6

not volatile
million times slower than RAM (milliseconds)
cheaper (perGB)

Front 7

capacity unit

Back 7

byte

Front 8

1 KB = bytes
1MB = KB = bytes

Back 8

1024 = 2^10
1024 = 2^20

Front 9

speed unit in computer

Back 9

Hertz (Hz) = 1 cycle per second

Front 10

1 MHz = Hz
1 GHz = Hz

Back 10

1 million
1 billion

Front 11

first computer were glorified calculator--characteristics

Back 11

had a store which held data to work on
instructions had to be entered manually in front panel, switches or cables
very slow but more accurate than humans

Front 12

John Von Neumann's idea

Back 12

put instructions in "store" RAM so that computer can access them as fast as mechanically possible

Front 13

after RAM idea

Back 13

suddenly computers were faster and multi-purpose
change the program in memory and change behavior of the machine
all machine built after that are called von Neumann machines
both instructions and data are in the RAM when processed

Front 14

low level language

Back 14

machine language or assembly language

Front 15

machine language

Back 15

binary = patterns of 0 and 1
very close to how the machine hardware works, many small steps

Front 16

high level language

Back 16

more like people think
portable

Front 17

example of language level----telling a robot to get out of a room

Back 17

machine language = take a step, raise arm, grasp knob, turn knob,.....
assembly language = leave through door
high level language = get outta here!!!

Front 18

compiler

Back 18

source code => object code(executable) --- it doesn't execute

Front 19

interpreter

Back 19

read, translate, and execute a program piece by piece

Front 20

why interpreter is considered easier to develop in?

Back 20

can get faster feedback on code, try things out more easily than a compiled language

Front 21

component of IDE

Back 21

editor, translator, linker, loader, debugger

Front 22

creator of python

Back 22

Guido van Rossum

Front 23

python named after

Back 23

Monty Python's Flying Circus

Front 24

two modes in python

Back 24

shell--simple execution
program mode--an editor

Front 25

codelens in textbook

Back 25

more or less like a debugger
step by step execution of a program
shows variables as changed
only works on preprogrammed examples

Front 26

program

Back 26

a sequence of instructions of how to perform computation

Front 27

bug

Back 27

syntax, runtime, and semantics error

Front 28

syntax error

Back 28

syntax = rules about the structure of a program
will not run until the error is found
interpreter will find them in the programming language

Front 29

runtime error

Back 29

happens during the running of the program
called an exception (big read message in python interpreter)
ex. file is missing, wrong data type given by user, dividing by zero value

Front 30

semantic error

Back 30

error in meaning
runs but give incorrect result
testing with known input and output is the only way to find this

Front 31

natural languages

Back 31

human languages
ambiguous
redundant

Front 32

formal languages

Back 32

artificial(notations) strict in syntax, have to be precisely stated
not ambiguous(not supposed to be)
not redundant

Front 33

comments

Back 33

# totally ignored by the interpreter
used to explain the actions to a reader