COMPSCI 1210 ( COMP ORG)

Unit I - System Concept

@@**UNIT 1 - SYSTEM CONCEPT**@@

is a system that @@**uses**@@ @@**information technology (IT)**.@@

INFORMATION SYSTEM

The ____@@**provides**@@ @@**services using a compute**@@**r**, 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

1. Application layer
2. Presentation layer
3. Session layer
4. Transport layer
5. Network layer
6. Data link layer
7. 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 laye**r@@ 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 proces**@@**s**, 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 @@a**l 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.**@@

s**emaphore**

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 a**llows 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