Computer Science | Study of Everything

Embedded Operating System (Android) | CS

SungjaeSeptember 17, 2016January 2, 2017

Brief Information Name : Operating System 운영체제 Lecturer : Ahn Woohyun 안우현 Semester : 2016 Fall Major?: BE,?Computer Science and Engineering Textbook 박성근 (2014)『이것이 안드로이드다』한빛미디어 김상형 (2016)『안드로이드 프로그래밍 정복 1』한빛미디어 김상형 (2016)『안드로이드 프로그래밍 정복 2』한빛미디어 Syllabus : Syllabus_2016-5-2__Embedded Operating System.pdf In?short Programming Android programs Review the Tests Midterm: Know the code routine for a certain […]

The Process of Java Compilation and Execution

SungjaeJuly 26, 2016July 26, 2016

Studying ‘VBA’

SungjaeMay 24, 2016

Summary VBA is an abbreviation of Visual Basic for Application. Abbreviated as VBA, Visual Basic for Applications is a programming language that is similar to Visual Basic, only it is embedded in an individual Microsoft application such as Excel or Access. Using VBA you can create macros or small programs that perform tasks within the […]

Implementing the File System | Assignment 3 | Operating System

SungjaeMay 22, 2016July 15, 2016

Brief Information Title: Implementing?the File System Hand-in date: 2016-05-17 Tue. Due date (1st): 2016-05-29 Sun. Due date (2nd):?2016-05-31 Tue. Due date (3rd): 2016-06-26 Sun. How to do the assignment: (pdf files) Homework 3 Homework 3: appendix 과제3 변경 및 중요사항(Homework 3: changes and important notices) Trace 2016-05-21 Sat. 23:13: Read the instructions. Try to implement […]

Implementing a Buffer Cache | Assignment 2 | Operating System

SungjaeApril 15, 2016July 15, 2016

Brief Information Title: Implementing a Buffer Cache Hand-in date: 2016-04-14 Mon. Due date: 2016-05-13 Wed. How to do the assignment: (pdf files) Operating System) Assignment 2) Homework2-1(partially edited by SJ).pdf Operating System) Assignment 2) Homework2-2(partially edited by SJ).pdf Trace 2016-04-12 Tue.: Homework 2-1.pptx handed in. The file was explained on this day. 2016-04-14 Thu.: Homework […]

Interconnected One Hash Table and Two Doubly Linked Lists | Assignment 1 | Operating System

SungjaeMarch 20, 2016July 15, 2016

How to do the assignment: Operating System) Assignment 1) Instruction.pdf Trace 2016-03-19 Sat.: Developing environment has been set. I made a tutorial to set the environment. 2016-03-19 Sat.: Three functions are implemented: GetObjectFromObjFreeList,?InsertObjectIntoObjFreeList,?InsertObjectToTail, and?InsertObjectToHead 2016-03-20 Sun.: All implemented. I have matched the implemented code and the instruction one by one. 2016-03-28 Mon.: I got the […]

Operating System Concepts. 9th Ed. by A. Silberschatz and P. B. Galvin (2012) Wiley

SungjaeMarch 15, 2016

Title: Operating System Concepts Authors:?A. Silberschatz, P. B. Galvin Publisher: Wiley Published Year: 2012 Contents Part 1:?Overview Chapter 1: Introduction Chapter 2: Operating-System Structures Part 2: Process Management Chapter 3: Processes Chapter 4: Threads Chapter 5: Process Synchronization Chapter 6: CPU Scheduling Chapter 7: Deadlocks Part 3: Memory Management Chapter 8: Main Memory Chapter 9: […]

Operating System | CS | Course

SungjaeMarch 4, 2016June 27, 2016

Brief Information Name : Operating System 운영체제 Lecturer : Ahn Woohyun 안우현 Semester : 2016 Spring Major?: BE,?Computer Science and Engineering Textbook Silberschatz, A., Galvin, P. B. & Gagne, G. (2008) Operating System Concepts. 8th Ed.?Wiley Syllabus 😕Syllabus_2016-5-1__Operating System.pdf In?short Assignments [Assignment 1] Interconnected One Hash Table and Two Doubly Linked Lists | Operating System […]

The Empty String, the Empty List, and Zero All Evaluate to False

SungjaeMarch 3, 2016March 3, 2016

The empty string, the empty list, the empty dictionary, the empty set, and zero all evaluate to False.

bool('') # the empty string
Out[1]: False

bool('a non-empty string') # a non-emepty string
Out[2]: True

bool(list()) # the empty list
Out[3]: False

bool(['a non-empty list']) # a non-empty list
Out[4]: True

bool(dict()) # the empty dictionary
Out[5]: False

bool({'key':'value'}) # a non-empty dictionary
Out[6]: True

bool(set()) # the empty set
Out[7]: False

bool({'a non-empty set'}) # a non-empty set
Out[8]: True

bool(0) # zero
Out[9]: False

bool(1) # a non-zero
Out[10]: True

bool('') # the empty string

Out[1]: False

bool('a non-empty string') # a non-emepty string

Out[2]: True

bool(list()) # the empty list

Out[3]: False

bool(['a non-empty list']) # a non-empty list

Out[4]: True

bool(dict()) # the empty dictionary

Out[5]: False

bool({'key':'value'}) # a non-empty dictionary

Out[6]: True

bool(set()) # the empty set

Out[7]: False

bool({'a non-empty set'}) # a non-empty set

Out[8]: True

bool(0) # zero

Out[9]: False

bool(1) # a non-zero

Out[10]: True

Conversion Between Str and Bytes

SungjaeMarch 2, 2016March 2, 2016

Diagram: Conversion Between Str and Bytes Conversion to String

def to_str(bytes_or_str):
    if isinstance(bytes_or_str, bytes):
        # bytes_or_str is bytes.
        value = bytes_or_str.decode('utf-8')
    else:
        # bytes_or_str is not bytes, but str.
        value = bytes_or_str
    return value

def to_str(bytes_or_str):

if isinstance(bytes_or_str, bytes):

# bytes_or_str is bytes.

value = bytes_or_str.decode('utf-8')

else:

# bytes_or_str is not bytes, but str.

value = bytes_or_str

return value

>>> bytes_ex = b'This is a string.'
>>> str_ex = 'This is a string'
>>> to_str(bytes_ex)
'This is a string'
>>> to_str(str_ex)
'This is a string'

>>> bytes_ex = b'This is a string.'

>>> str_ex = 'This is a string'

>>> to_str(bytes_ex)

'This is a string'

>>> to_str(str_ex)

'This is a string'

Conversion To Bytes

def to_bytes(bytes_or_str):
    if isinstance(bytes_or_str, str):
        # bytes_or_str is str.
        value = bytes_or_str.encode('utf-8')
    else:
        # bytes_or_str is not str, but bytes
        value = bytes_or_str
    return value

def to_bytes(bytes_or_str):

if isinstance(bytes_or_str, str):

# bytes_or_str is str.

value = bytes_or_str.encode('utf-8')

else:

# bytes_or_str is not str, but bytes

value = bytes_or_str

return value

>>> bytes_ex = b'This is a string.'
>>> str_ex = 'This is a string'
>>> to_bytes(bytes_ex)
b'This is a string'
>>> to_bytes(str_ex)
b'This is a string'

>>> bytes_ex = b'This is a string.'

>>> str_ex = 'This is a string'

>>> to_bytes(bytes_ex)

b'This is a string'

>>> to_bytes(str_ex)

b'This is a string'

Write a?File in Write Binary Mode (‘wb’)

with open('binary.txt', 'wb') as f:
    f.write(to_bytes(str_ex))

with open('bytes.txt', 'wb') as f:
    f.write(to_bytes(bytes_ex))

with open('binary.txt', 'wb') as f:

f.write(to_bytes(str_ex))

with open('bytes.txt', 'wb') as f:

f.write(to_bytes(bytes_ex))

Write a?File in Write Character?Mode (‘w’)

with open('str.txt', 'w') as f:
    f.write(to_str(str_ex))

with open('str.txt', 'w') as f:
    f.write(to_str(bytes_ex))

with open('str.txt', 'w') as f:

f.write(to_str(str_ex))

with open('str.txt', 'w') as f:

f.write(to_str(bytes_ex))