[Information Processing Technician] Final review of exam scope

Before the exam, read through to make sure you understand the information below!

? Software testing principles

Testing is about revealing that a combination of beings exists.

Perfect testing is impossible

Start testing early in development

Cohesion focus - majority of defects are found in a small number of modules

Pesticide Paradox - Repeated testing with the same test cases does not find new bugs

Testing is context dependent

Error - the sophistry of absence

? data mining

Technology to systematically and automatically find statistical rules or patterns in large-scale stored data

? 3 elements of protocol

Syntax – specifications of data formats, coding, signal levels, etc. for transferring information between systems.

Meaning - Control information for information transfer between systems and regulations for coordination and error handling

Timing – regulating the speed and order of information transfer between systems.

? XML

XML defines the transmitted data structure in the same form for the convenience of data linkage between transmission and reception systems.

? JSON

It is an open standard format that uses human-readable text to convey data objects consisting of attribute-value and key-value pairs for asynchronous browser-server communication.

It is the main data format replacing XML.

? Non-preemptive scheduling algorithm

Priority - By highest priority, or in order of first arrival if priorities are the same (FCFS)

Deadline - Processed within a specified time frame

FCFS - first come first service, CPU is allocated according to the order in which processes arrived in the waiting queue.

SJF - shortest job first, processes with the smallest work time in the preparation queue are performed first, starvation phenomenon may occur.

HRN

- highest response rate next, selects the one with the highest current response rate among waiting processes.

- SJF-style security

- (Waiting time + Service time) / Service time

? Transaction Features

Atomicity - the smallest unit of work that cannot be decomposed.

Consistency - the characteristic of maintaining a consistent database state at all times after transaction success/failure.

Isolation - A situation in which other transactions cannot access the intermediate results of operations generated while a transaction is running.

Durability - The property of permanently storing the results of a successful, completed transaction in the database.

? Land Attack Land Attack

This is an attack technique that violates system availability by sending a packet with the same source IP and destination IP address, causing the recipient to send a response to itself.

? Hash encryption algorithm (one-way)

MD5 - MD4 improved encryption algorithm, generates 128bit hash value

SHA-1 - Designated by NSA as a US government standard, used in DSA (digital signature algorithm), generates 160-bit hash value

SHA-256/384/512 - 256bit hash value generation

HAS-160 - Developed for domestic standard signature algorithm, taking advantage of MD5 and SHA1

? coupling degree

The lower the degree of connection and interdependence with external modules, the better.

In the types of coupling below, the further down you go, the lower the coupling, and it can be said to be of good quality.

Content Cohesion - Cohesion when variables or functions within other modules are used in other modules

Common coupling - Coupling when referencing and updating global variables declared outside the module rather than parameters

External coupling - Cohesion when two modules share an externally introduced data format, communication protocol, or device interface

Control coupling - Coupling when not only the object to be processed is transmitted, but also the control elements of how to process it are transmitted.

Stamp Cohesion - Cohesion when arrays, objects, structures, etc. are passed through the interface between modules.

Data Cohesion - Cohesion when interaction between modules occurs only through parameters passed through the interface between modules.

? Cohesion

The higher the degree of connection between internal components, the better.

In the types of cohesion below, the further down you go, the higher the cohesion, and it can be said to show good quality cohesion.

Accidental cohesion - Cohesion when each component within a module is unrelated

Logical cohesion - Cohesion when processing elements with similar characteristics or classified into a specific form are processed in one module

Temporal cohesion - Cohesion when activities that need to be processed at a specific time are processed in one module rather than related functions.

Procedural cohesion - Cohesion when a module has multiple related functions and the components within the module perform their functions sequentially.

Communication cohesion - Cohesion when activities that perform different functions using the same input and output are gathered together

Sequential cohesion - Cohesion when output from one activity within a module is used by another activity.

Functional cohesion - Cohesion when all functions within a module are performed for a single purpose.

? bubble sort

It is widely used because the code is simple, but the time complexity is long, O(N2).

Elements that are out of order are sorted in order of size while continuously exchanging them with adjacent elements. Even if it is already in the final position, it may be exchanged through adjacent comparison, and in order to move from the leftmost to the rightmost, all elements must be exchanged. In other words, there is a significant time cost.

? Swithdoor

If there is no separate break statement in each case, all cases are executed in order starting from the corresponding case.

? release notes

Header / Overview / Purpose / Issue Summary / Reproducible Items / Modifications/Improvements / User Impact / Software Support Impact / Notes / Disclaimers / Contact Information

The header includes information such as document name, product name, version number, release date, reference date, and note version.

? Denormalization

Denormalization = Seminormalization = Denormalization

It is a data modeling technique that performs duplication, integration, and separation of normalized entities, properties, and relationships to improve performance and simplify development operations.

Merge tables / Split tables (partitioning) / Add duplicate tables / Duplicate columns / Add duplicate relationships

? OSI Layer 7

Application Layer Application Layer

Application service connection between user and network, data generation

Protocol (HTTP, FTP) / Transmission unit (data) / Equipment (host)

Presentation Layer

Data format setting, code exchange, encryption and decryption

Protocol (JPEG, MPEG) / Transmission unit (data) / Equipment (host)

Session Layer Session Layer

Logical connection between transmission and reception, connection access, synchronization control

Protocol (RPC, NetBIOS) / Transmission unit (data) / Equipment (host)

Transport Layer

Connection between sending and receiving processes, ensuring reliable communication, data segmentation, reassembly, flow control, error control, congestion control

Protocol (TCP, UDP) / Transmission unit (segment) / Equipment (L4 switch)

Network Layer Network Layer

Provides an optimized path for data transmission between terminals

Protocol (IP, CMP) / Transmission unit (packet) / Equipment (router)

Data Link Layer DataLink Layer

Data transmission between adjacent systems, transmission error control, synchronization, error control, flow control, line control

Protocol (HDLC, PPP) / Transmission unit (frame) / Equipment (bridge, switch)

Physical Layer

Electrical signal conversion to send bit information of 0 and 1 to the line

Protocol (RC-232C) / Transmission unit (bit) / Equipment (hub, router)

? Application performance indicators

Throughput / response time / elapsed time / resource utilization

? Fan-In Fan-in, Fan-Out Fan-out

? business continuity plan

Disaster recovery time RTO recovery time object

During information system operation, the time until the server goes down, natural disaster, system failure, etc., or work is restored and restarted.

BIA business inpact analysis

Business impact analysis to build a BCP that examines the impact and loss assessment over time, assuming major operational losses due to failure or disaster

RPO recovery point object

When data is recovered from the point of business interruption and resumes normal operation, data loss is acceptable, and recovery target point is selected in the event of a disaster.

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