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UNIT 1 - SYSTEM CONCEPT
is a system that uses information technology (IT).
INFORMATION SYSTEM
The ____provides services using a computer, and a computer operates with a combination of hardware and software.
INFORMATION SYSTEM
an INFORMATION SYSTEM used inside an enterprise, or provided as a service to users, requires the design and construction of IT infrastructures, such as)___ and ___ design and development.
hardware & software
___ designs the software components and operations, such as the connection of the software components and constraints based on software architecture.
Software
Just like software, ___designs and develops the hardware architecture.
hardware
refers to the architecture for a system to provide services, based on hardware and software architecture.
SYSTEM ARCHITECTURE
In a broader definition, it refers to all architecture,
including the _, _, _,
for constructing an information system.
application architecture (AA)
data architecture (DA)
technical architecture (TA)
A narrow definition refers to the document that defines the ___ of hardware, such as a______ , ___, ___and , and certain software parts, such as ___ and ___
configuration and relationship
server, storage, network, and security
Os and middleware
A ____ is a document that defines the structure of an information system provided to support the business process required to achieve the objective of an enterprise.
system architecture
A system architecture is divided into _, , -
application architecture (AA)
data architecture (DA)
technical architecture (TA)
it defines the structure of hardware, such as a server, network, and security, as well as the distributed structure of middleware operating on the hardware,
technical architecture (TA)
it defines the data structure to assure data integrity,
data architecture (DA)
it defines the software components and the relationship and constraints of said defined components.
application architecture (AA)
Narrow definition of
A ____ refers to the structure of an information system, which includes principles and guidelines that define the components, such as hardware, software, security, interactions, and constraints.
system architecture
The following table shows the types of detailed architecture defined in system architecture. ( click to see)
Server design Architecture
Network Design Architecture
storage design architecture
What are the Components of System Architecture
Server
Network
Storage
Security
It provides the computing power of an information system. The information system uses this computing power to process the business logic and data by running the application programs.
its components include the stacked structures of the computer's hardware, OS, middleware, and application programs.
Server
it connects the information system components for communication.
process communication between servers, between servers and storage units, and between the enterprise's internal and external networks.
Network
holds the data of an information system.
The information system uses this computing Power to process the business logic and data by running the application programs.
Storage
Storage is categorized into 4 types according to how it stores data.
Block storage
File storage
Object storage
Direct Access Storage (DAS)
saves data in fixed block units, like 16KB and 64KB. It stores the OS, such as MS Windows, Linux, and Unix.
Block storage
saves data in file units, instead of in fixed blocks. Network Attached Storage (NAS), widely used as the shared file repository, is a type of file storage.
File storage
saves data in object units, instead of in fixed blocks or files. It is mostly used in cloud storage. Storage types can also be categorized by their connection method.
Object storage
__is mounted in each server, NAS is connected through a network, and Storage Area Network (SAN) is connected through the network used exclusively for storage.
Direct Access Storage (DAS)
configured through the network connection.
Security
System architecture classification according to the system layout
Centralized architecture
Multi-region
arranges all the systems in a centralized place.
stores and operates the system and data from an integrated center. It configures an integrated database on a large-capacity server and it has a relatively simple system configuration.
Centralized architecture
distributed architecture operates the system by distributing regional and application systems regionally.
Each region manages the distributed data using small or medium-sized servers. This structure can reduce the load of each server, since it distributes the user load.
Multi-region distributed system architecture
Classification according to how the application programs are provided
Client-server architecture
Web system architecture
The architecture places system functions in the servers and clients and configures them to use the service, depending on the business size or environment.
Client-server architecture
The architecture runs the server's application programs, and the client uses the service with a web browser. It generally consists of a web server, a web application server, and a database server.
The ___assures stable performance, and the program reusability is high.
Web system architecture
middleware
Classification by system layer
Two-tier architecture
Three-tier architecture
The function and role of each system component are classified by __ or ____
tier, or layer
The most widely known layer is the___ which shows the network structure.
OSI 7 layer,
difference of layer and tier
layers refer to structures from a logical point of view
and tiers refer to structures from a physical perspective.
An information system is divided into a___
presentation layer
a business logic layer
data layer
different layer in Information System
stores and processes data in the server and processes business logic and presentation for the client.
It is generally the same structure as the client-server architecture.
Two-tier architecture
a structure created to overcome the limitations of two-tier architecture,
and it is also called multi-tier architecture.
This structure has an additional tier between the presentation tier and the data tier, in order toprocess business logic to be flexible and scalable.
Three-tier architecture
__refers to a computer or program that provides information or services to users through a network. It provides the computer power needed for the information system services.
“Server”
The concept of the server was created when __ started making a server called the mainframe.
IBM
The term ___ refers to a large steel enclosure, like a cabinet, that houses the CPU and the main memory.
mainframe
The mainframe began downsizing gradually in __when the attention to super Unix servers, such as HP. Sun, and Silicon Graphics, increased.
1997
Downsizing refers to replacing a mainframe server with a ___
super Unix server.
regarded as the beginning of modern computers.
Turing Machine,
Who and When Turing Machine Invented
Allen Turing in 1936,
This Turing Machine proved the ___
mathematical concepts and calculation processes
known as the first programmable general-purpose computer. Using 18,000 vacuum tubes, it weighed 30 tons and was literally as large as a house. And it was create in__
ENIAC, created in 1946,
the first computer that embedded the program in a memory unit, it was proposed by and developed in
EDSAC.
John von Neumann in 1949
Unit II - Network Concept
a standardized communication rule for sending and receiving data through a network.
PROTOCOL
responsible for most Internet-related standard protocols.
IETF (Internet Engineering Task Force)
responsible for wireless communication protocols such as GSM, CDMA, UMTS, LTE, and LTE-A.
3GPP (Third Generation Partnership Project) and 3GPP2
responsible for protocols related to telephones.
ITU-T (International Telecommunication Union Telecommunication Standardization Sector)
commonly referred to when dealing with networks.
ISO's OSI reference model, or OSI layer
ISO is derived from the Greek word “__”?
ioo¢ (isos)
ISO is derived from the Greek word “ioo¢ (isos)’, meaning “__”,
identical
IOS stands for?
International Organization for Standardization (IOS).
OSI is an abbreviation of?
Open Systems Interconnection.
The Internet protocol layer is based on the?
ARPANET reference model,
OSI Reference Model layers
Application layer
Presentation layer
Session layer
Transport layer
Network layer
Data link layer
Physical layer
Application programs, such as web (HTTP), DNS, telnet, FTP, and email sending/receiving (SMTP/POP3/IMAP4), allow access to services on other layers.
APPLICATION LAYER
Also called the host-to-host transport layer,
It is equivalent to the transport layer in the OSI reference layer.
TRANSPORT LAYER
Also called the network layer, it is responsible for addressing and routing functions.
It is equivalent to the network layer in the OSI reference layer.
INTERNET LAYER
Also called the network access layer,
the network interface layer has the role of actually sending and receiving TCP/IP packets through physical media, such as IEEE 802.3 and IEEE 802.11 WIFI.
NETWORK INTERFACE LAYER
Internet users come across many terms related to numbers, such as a MAC address, an IP address, and a port number.
Internet Address System
the address system used by the data link layer, is used to transfer frames between the physically connected nodes.
MAC (MEDIUM ACCESS CONTROL)
the address system of the network layer to transfer datagram between two hosts/ routers.
It facilitates data to be transferred from the source node to the destination node, through multiple Internet networks.
INTERNET PROTOCOL
transfer messages between two processes (running applications) is responsible for the connection between the web browser
PORT NUMBER
is a leading organization responsible for Internet-related standards.
It defines the basic protocols for Internet transmissions,
IETF (Internet Engineering Task Force)
Unit III – Operating System
A. Operating System (OS)
B. Process and Thread
C. Process Synchronization and Deadlock
D. Memory Unit Management
E. Scheduling
F. Virtual Memory Unit
G. File System
H. Input/ Output System
B. Process and Thread
refers to a running program, and in today’s concurrent multi-process environment, it is a work unit of a time-sharing system.
A process
A process has a distinct process status during its lifecycle
Process status
Created: A process is created but is not running by the OS.
Preparing: The process is waiting for the CPU allocation to run.
Running: The process has the CPU allocation.
Finished: The process has completed its running, and the CPU allocation is released.
Standby: The process ran after getting the CPU allocation, and is waiting for an event, such as the completion of input or output.
stores information necessary for process management.
Process control block (PCB)
The process that creates other processes
parent process,
newly created process is called
child process.
A child process can create another child process, and this relationship is formed in a___?
tree structure,
After completing the last code of the program, the process requests the OS to delete the process with the "exit()" system cal,
Process termination
a basic unit for using a CPU
shares the memory unit, such as codes, data, and files, and creates its own register and stack.
thread
thread is a basic unit for using a CPU and is al called a?
lightweight process.
a case in which a thread exists for a process, and a process,
single-thread process
having multiple threads, is called a
multi-threaded process.
C. Process Synchronization and Deadlock
refers to two or more parallel processes simultaneously accessing and changing the same data, or the order of manipulating the data affecting the execution result.
race condition
The part of the code that implements such a request is called the
entry section
The exit section is after the critical section, and the rest of the code is collectively called the
remainder section
the hardware method is not feasible, since it deteriorates the system efficiency in a multiprocessor environment.
Another way is to use a__ which is a synchronization tool.
semaphore
The semaphore, ’S’, is an integer variable, and only the___operation (wait) and__operation (signal) are enabled.
P and V
There may be a case when the status of a process in “standby” is never changed because the requested resource is allocated to other standby processes. This state is called the __
deadlock.
___ cannot finish the running program, and the system cannot start other tasks because the resource is tied to other processes.
deadlocked processes
D. Memory Unit Management
technique of running processes, even if they are not present in the memory unit.
This technique allows a user program that is larger than the physical memory unit to run.
Virtual memory
technique of searching for the best way to allocate processes to the available main memory area when a process requests the memory unit for a new use.
Memory unit allocation technique
Memory space is allocated when the memory is requested and recollected after use.
Fragmentation problem
Using the first-fit, best-fit, and worst- fit techniques to allocate the memory unit can cause __,
external fragmentation
__If the memory is partitioned into a fixed size to provide multiple fixed-sized available spaces to processes, it may be slightly larger than the required space.
The remaining space is called the ___
Fragmentation problem
internal fragmentation
merges small-sized available memory,
Compaction technique
merges spaces with adjacent addresses in the unused empty space list in order to create a larger space and to prevent multiple small spaces
Coalescing technique
Note 
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