Types of Blockchain Applications Cryptocurrency Problems of Trusted Third Party - Financial Institute highly relies on trusted third parties A third party became a single point of failure Delay leaves customers at risk, temporarily unsure about the state Attacks on concentrated data Third Parties' monopolies Blockchain can reduce the risk of the trusted third-party authority in a situation where..
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Simple Introduction to Blockchain History Satoshi Nakamoto released the white paper in 2008: "purely peer-to-peer version of electronic cash" Bitcoin was offered up to the open source community in 2009 Around 2014, blockchain technology becomes more than cryptocurrency In 2015, Ethereum launched: can be used to build smart contract Cryptocurrency is just application using blockchain. Blockchain ..
Mode Bit Mode Bit: 하드웨어적으로 두 가지 operation 지원 Mode Bit == 1 : 사용자 모드 - 사용자 프로그램 수행 Mode Bit == 0 : 모니터 모드 (= 커널 모드, 시스템 모드) - OS 코드 수행, System call 수행 보안과 관련된 중요한 명령어는 모니터 모드에서만 수행 가능한 특권명령 Interrupt나 Exception 발생 시 하드웨어가 Mode Bit를 0으로 바꿈 사용자 프로그램에게 CPU를 넘기기 전에 Mode Bit를 1로 바꿈 Timer Timer 타이머 시간이 0이 되면 타이머 인터럽트를 발생시켜서 운영체제에 제어권이 넘어가도록 한다. CPU를 특정 프로그램이 독점하는 것으로부터 보호 Time sharing을 구현하거나 현재 시간을 계산할..
인터넷 개요 What's the Internet? Nuts and bolts View Internet: network of networks host = end system = end node = termial = station protocols control sending, receiving of messages Internet standards: RFC, IETF Service View infrastructure that provides services to applicaations provide programming interface to application What's a protocol? Protocols define format, order of messages sent and received..
운영체제(Operation System 개요 운영체제(Operation System, OS) 정의 운영체제: 컴퓨터 하드웨어 바로 위에 설치되어 사용자 및 다른 소프트웨어와 하드웨어를 연결하는 소프트웨어 계층 좁은 의미의 OS: 커널 - 운영체제의 핵심 부분으로 메모리에 상주하는 부분 넓은 의미의 OS: 커널 뿐 아니라 각종 주변 시스템 유틸리티를 포함한 개념(리눅스, 윈도우 등) 운영체제의 목적 컴퓨터 시스템을 편리하게 사용할 수 있는 환경을 제공 - 동시 사용자가 각각 독자적 컴퓨터에서 수행되는 것 같은 환상 제공 컴퓨터 시스템의 자원을 효율적으로 관리 - 단일 작업만 가능했는데, 다중 작업도 가능 운영체제의 분류 동시 작업 가능 여부 단일 작업: 한 번에 하나의 작업만 처리 ex. MS-DOS(cm..
Basic Steps to create and Configure a bucket Create a Bucket 1. Give the bucket a name The name must be globally unique Bucket name include: 3-63 characters, lowercase letters, numbers, dots(.), hyphens(-) Bucket name must begin and end with a letter or number conbination of a bucket name, key, version ID uniquely identifies the object https://bucket-name.s3.amazonaws.com/folder-name/filename.zi..
Introduction to Cloud Storage On Premises storage: Data are shared through your local network Cloud storage: Data are shared through the internet -> outside service provider like AWS hosts your data Benefits of Cloud Storage Cost efficient: no huge up-front fee Secure: data is saved across multiple servers Accessible: multiple users can access Scalable Managed: cloud service provider manages the..
Lanching options AWS Management Console AWS Command Line Interface (CLI) AWS Software Development Kit (SDK) Other AWS services: AWS CloudFormation, AWS OpsWorks, AWS Elastic Beanstalk Amazon EC2 Lifecycle States Pending - Not billed preparing to enter the running state when it launching for the first time or when it starting after being in the stopped state. Running - Billed running and ready fo..
7 Steps to launching an EC2 Instance 1. Instance name and tags Tag Tag is a label that you can assign to an AWS resource key - value(optional), Name of the instance is the default tag tag limit per EC2 resource is 50 tags can search resources by key or by value or by combination of keys and values Benefits of Using Tags Resource organization: search & filter by tag, create groups of resources Co..
Lec 04-1: Intro to Amazon EC2 Intro to Computing Computing is the brain that makes IT application work. It collects, analyzes, processes, distributes data Main Components of Computing CPU runs and processes the instructions that it is given = makes the calculation possible RAM store data, temporary storage, main memory (DRAM) Hard drive long-term storage, stores the boot files and files that you..
