Bangladesh Agricultural Research Institute, Assistant Maintenance Engineer, 2024ok

Bangladesh Agricultural Research Institute(BARI)

Post: Assistant Maintenance Engineer
Exam Date: 10.05.2024

1. What is Multithreading System?

Multithreading is a technique where a single process is divided into multiple smaller execution units called threads that run concurrently.

Thread: A thread is a lightweight process and the smallest unit of execution within a process.

Working: Multiple threads run simultaneously within the same process and share resources like CPU, memory, and I/O.

Purpose: It improves performance, responsiveness, and efficient resource utilization.

Concurrency: Multithreading enables concurrency or parallelism within a process.

Example: In a web browser, each tab works as a thread; in MS Word, one thread handles typing while another handles formatting.

Multithreading হলো এমন একটি technique যেখানে একটি process-কে একাধিক ছোট execution unit (thread)-এ ভাগ করা হয় এবং এই thread-গুলো একসাথে কাজ করে।

Thread Thread হলো একটি lightweight process এবং process-এর সবচেয়ে ছোট execution unit।

Working: একাধিক thread একই process-এর মধ্যে একসাথে চলে এবং CPU, memory ও I/O resource share করে।

Purpose: এটি performance বৃদ্ধি করে, system-এর response দ্রুত করে এবং resource efficient করে।

Concurrency: Multithreading-এর মাধ্যমে একটি process-এর মধ্যে concurrency বা parallelism অর্জন করা যায়।

Example: Browser-এ প্রতিটি tab একটি thread-এর মতো কাজ করে; MS Word-এ একটি thread typing handle করে এবং অন্যটি formatting করে।

2. Advantages of CPU Scheduling Algorithm.

Advantages of CPU Scheduling Algorithm

Better CPU Utilization: Keeps the CPU busy by efficiently managing processes.

Improved Throughput: Increases the number of processes completed in a given time.

Reduced Waiting Time: Minimizes the waiting time of processes in the ready queue.

Faster Response Time: Provides quick response to user requests, especially in interactive systems.

Fair Resource Allocation: Ensures all processes get fair access to CPU resources.

CPU Scheduling Algorithm-এর সুবিধা

Better CPU Utilization: CPU-কে সর্বদা ব্যস্ত রাখে এবং efficientভাবে process পরিচালনা করে।

Improved Throughput: নির্দিষ্ট সময়ে বেশি সংখ্যক process সম্পন্ন করতে সাহায্য করে।

Reduced Waiting Time: Ready queue-তে process-এর অপেক্ষার সময় কমায়।

Faster Response Time: User-এর request-এ দ্রুত response দেয়, বিশেষ করে interactive system-এ।

Fair Resource Allocation: সব process-এর মধ্যে CPU resource সমানভাবে বণ্টন নিশ্চিত করে।

3. Write a TCP/UDP used service name?

Common TCP/UDP Service Names:

TCP services:
• HTTP (Web) – Port 80
• HTTPS – Port 443
• FTP – Port 21
• SMTP – Port 25
• Telnet – Port 23

UDP services:
• DNS – Port 53
• DHCP – Port 67/68
• TFTP – Port 69
• SNMP – Port 161

4. Write Class A private IP range.

Class A Private IP Range: 10.0.0.0 to 10.255.255.255

5. Which protocol maps an IP address to a MAC address?

The protocol that maps an IP address to a MAC address is ARP (Address Resolution Protocol)

6. How many TCP/IP layers? Write its layer name.

7. GPU stands for ______ ?

GPU stands for Graphics Processing Unit.

8. NAT stands for ______ ?

Network Address Translation

9. What is the main purpose of a firewall in a computer network?

Purpose of Firewall in Computer Network

The main purpose of a firewall is to protect a computer network by monitoring and controlling incoming and outgoing network traffic.

Security: Prevents unauthorized access from external networks.

Traffic Control: Allows or blocks data packets based on predefined rules.

Protection: Protects the system from hackers, malware, and cyber attacks.

Access Management: Controls which users or applications can access the network.

Firewall-এর মূল উদ্দেশ্য

Firewall-এর প্রধান উদ্দেশ্য হলো network-কে সুরক্ষিত রাখা এবং incoming ও outgoing traffic নিয়ন্ত্রণ করা।

Security: বাইরের unauthorized access প্রতিরোধ করে।

Traffic Control: নির্দিষ্ট নিয়ম অনুযায়ী data packet allow বা block করে।

Protection: hacker, malware এবং cyber attack থেকে system-কে রক্ষা করে।

Access Management: কোন user বা application network access করতে পারবে তা নিয়ন্ত্রণ করে।

11. DRAM stands for ______ ?

DRAM stands for Dynamic Random Access Memory.

10. How many collision domains are created when you segment a network with a 12-port switch?

A switch creates one collision domain per port.
So, for a 12-port switch:
Collision domains = 12

12. Write 4 topology name?

Four Network Topologies:
• Bus Topology
• Star Topology
• Ring Topology
• Mesh Topology

13. BGP stands for ______ ?

BGP stands for Border Gateway Protocol

14. Which routing protocol uses Dijkstra Algorithm?

The routing protocol that uses Dijkstra’s Algorithm is OSPF (Open Shortest Path First).

15. Which device operates at the Network Layer of the OSI model?

The device that operates at the Network Layer (Layer 3) of the OSI model is a Router.

16. What type of RR Scheduling Algorithm: Preemptive / Non-Preemptive?

The Round Robin (RR) scheduling algorithm is a Preemptive scheduling algorithm.

Type: It is a preemptive algorithm.

Working: Each process is given a fixed time slice called time quantum.

Preemption: If a process does not finish within its time quantum, it is preempted and moved to the end of the ready queue.

Advantage: Ensures fair CPU allocation among processes.

Round Robin (RR) scheduling algorithm একটি Preemptive scheduling algorithm।

Type: এটি একটি preemptive algorithm।

Working: প্রতিটি process-কে একটি নির্দিষ্ট সময় (time quantum) দেওয়া হয়।

Preemption: যদি process নির্দিষ্ট সময়ে শেষ না হয়, তাহলে তাকে stop করে ready queue-এর শেষে পাঠানো হয়।

Advantage: সব process-এর মধ্যে CPU সমানভাবে ভাগ করে দেয়।

17. What is the base of 5th generation Computer?

The base of 5th generation computers is Artificial Intelligence (AI).

18. What is CIDR?

CIDR (Classless Inter-Domain Routing)

CIDR is a method used in IP addressing that allows flexible allocation of IP addresses instead of fixed classes.

Purpose: To efficiently use IP address space and reduce wastage.

Notation: Written as IP address followed by /prefix (e.g., 192.168.1.0/24).

Working: The prefix indicates the number of bits used for the network portion.

Advantage: Improves routing efficiency and reduces size of routing tables.

CIDR (Classless Inter-Domain Routing)

CIDR হলো IP addressing-এর একটি পদ্ধতি যেখানে fixed class-এর পরিবর্তে flexibleভাবে IP address বরাদ্দ করা হয়।

Purpose: IP address-এর সঠিক ব্যবহার নিশ্চিত করা এবং অপচয় কমানো।

Notation: IP address-এর পরে /prefix দিয়ে লেখা হয় (যেমন 192.168.1.0/24)।

Working: Prefix দ্বারা বোঝায় কতগুলো bit network অংশ হিসেবে ব্যবহৃত হচ্ছে।

Advantage: Routing efficient করে এবং routing table ছোট করে।

19. What is the function of the ARP protocol in a network?

ARP (Address Resolution Protocol) is used to map an IP address to its corresponding MAC address in a network.

Main Function: Converts logical IP address into physical MAC address.

Working: When a device wants to send data, it broadcasts an ARP request to find the MAC address of the destination IP.

Response: The device with the matching IP sends back its MAC address (ARP reply).

Usage: Used in local area networks (LAN) for proper data delivery.

ARP (Address Resolution Protocol) network-এ একটি IP address কে তার সংশ্লিষ্ট MAC address-এ রূপান্তর করতে ব্যবহৃত হয়।

Main Function: Logical IP address-কে physical MAC address-এ convert করে।

Working: যখন কোনো device data পাঠাতে চায়, তখন এটি ARP request broadcast করে destination-এর MAC address খুঁজে বের করে।

Response: যেই device-এর IP মিলে যায়, সে তার MAC address পাঠিয়ে ARP reply দেয়।

Usage: এটি LAN-এ data সঠিকভাবে পৌঁছানোর জন্য ব্যবহৃত হয়।

20. What is the difference between a process and a thread?

Definition: A process is an independent program in execution; a thread is a smaller unit of a process.

Memory: Each process has its own memory space; threads share the same memory of the process.

Communication: Process communication is slower (IPC required); threads communicate faster as they share memory.

Overhead: Process creation is heavy and time-consuming; thread creation is lightweight and faster.

Execution: Processes run independently; threads run within a process and depend on it.

Example: Opening different applications = processes; multiple tasks inside one application = threads.

Definition: Process হলো একটি independent program যা execute হয়; Thread হলো process-এর ছোট অংশ।

Memory: প্রতিটি process-এর আলাদা memory থাকে; thread একই process-এর memory share করে।

Communication: Process-এর মধ্যে communication ধীর (IPC লাগে); thread দ্রুত communicate করে কারণ তারা memory share করে।

Overhead: Process তৈরি করা heavy এবং সময়সাপেক্ষ; thread তৈরি করা lightweight এবং দ্রুত।

Execution: Process স্বাধীনভাবে চলে; thread process-এর ভিতরে নির্ভরশীলভাবে চলে।

Example: আলাদা application = process; একটি application-এর ভিতরে একাধিক কাজ = thread।

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Bangladesh Agricultural Research Institute(BARI) Post: Assistant Maintenance Engineer Exam Date: 10.05.2024

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Bangladesh Agricultural Research Institute(BARI)

Post: Assistant Maintenance Engineer
Exam Date: 10.05.2024