The document discusses the Domain Name System (DNS), explaining that it is a globally distributed database that translates human-friendly website addresses into computer-friendly IP addresses and vice versa. DNS uses a hierarchical system to organize domain names and resolve queries through recursive or iterative processes, with DNS messages containing header, question, answer, and additional record sections to facilitate name-address mapping.
A complete Coverage of DNS and its features. This ppt deals with well balanced practical and theoretical aspects of DNS. The best ppt for a novice learner.
The document discusses the Domain Name System (DNS), which translates domain names to IP addresses and vice versa. It describes the hierarchical structure of DNS with zones, resource records, and name servers. Primary and secondary name servers maintain authoritative data for zones, while caching name servers store previously looked up data to improve performance. The domain name resolution process involves queries to authoritative and caching name servers to map names to addresses.
The document discusses how the Domain Name System (DNS) works by translating domain names to IP addresses. It involves the following steps:
1) A user enters a domain name in their browser. Their computer first checks its local DNS cache for the IP address.
2) If not found locally, the computer queries a recursive DNS server, typically provided by the user's Internet Service Provider.
3) If the recursive DNS server doesn't have the IP address, it queries the root name servers which direct the query to the authoritative name servers for the top-level domain (e.g. .com, .org).
4) The authoritative name servers for the specific domain (e.g. ut
Learn about the essentials of the Domain Name System (DNS), including name resolution, different record types, roots, zones, authority and recursion.
See the full webinar and the rest of the series at https://www.thousandeyes.com/resources/intro-to-dns-webinar
The document is a presentation on DNS (Domain Name System) given by Mauood Hamidi for his dissertation. It covers definitions of DNS, different types of DNS servers, tools used for DNS queries, DNS records, how DNS works to resolve domain names to IP addresses, and components of the DNS system like zones, name servers, and security considerations. It aims to provide an overview of the key concepts and functioning of DNS.
The document discusses the Domain Name System (DNS). It describes DNS as a hierarchical and distributed database that maps hostnames to IP addresses. DNS uses a tree structure with nodes containing domain names that are read from the node up to the root. The document outlines the key components of DNS including fully and partially qualified domain names, zones, primary and secondary name servers, and the different top-level domains like generic, country, and inverse domains used for name to address and address to name lookups.
DHCP is a client-server protocol that assigns network parameters like IP addresses to devices from a server's address pool. A DHCP client broadcasts a request and the DHCP server responds with an offered address via acknowledgement packets. DNS translates human-friendly hostnames to IP addresses by querying a DNS server's address records, allowing users to access resources by name instead of numeric address. Together, DHCP and DNS simplify network configuration and access.
The Domain Name System (DNS) is a hierarchical distributed naming system for computers, services, or any resource connected to the Internet or a private network. It associates various information with domain names assigned to each of the participating entities. A domain name represents an Internet Protocol (IP) resource ultimately identifiable by a numeric IP address. DNS servers store records that map domain names to IP addresses and vice versa. The DNS hierarchy consists of root name servers at the top, authoritative name servers for top-level domains and their subdomains below them. When a user enters a domain name, the DNS server first checks its cache and if it doesn't find a match, it queries authoritative name servers to resolve the IP address associated with the domain name.
The document discusses the Domain Name System (DNS) which translates human-friendly domain names to IP addresses. It describes DNS as the internet's equivalent of a phone book. DNS uses a hierarchical, domain-based naming scheme and distributed database to implement this naming system. The DNS database contains resource records (RRs) that map domain names to IP addresses and other attributes. There are different types of name servers, including authoritative, caching, primary, and secondary servers that maintain the DNS database and resolve queries. DNS resolution can occur through either recursive or iterative queries to translate names to addresses.
This slide contains details about domain name servers (DNS).
It also contains Resolution of the Name Servers with Domain Name Structure with statistics table. The process of Name resolution is also explained with Recursive and iterative resolution processes.
DNS is a distributed database that translates hostnames to IP addresses. It operates through a hierarchy of root servers, top-level domain servers, and authoritative name servers. DNS provides additional services like load balancing and mail server aliasing. Queries are resolved through recursive or iterative lookups between clients and servers to map names to addresses.
Domain Name System (DNS) is a hierarchical naming system that maps domain names to IP addresses. DNS maintains the domain namespace and provides translation between domain names and IP addresses using DNS name servers and a communication protocol. DNS refers to the data query service, system of mapping names to IP addresses hierarchically, and DNS servers that translate host names to IP addresses. Before DNS was invented, host name to IP address mappings were stored in a file. DNS was developed in the 1980s and the dominant DNS software, BIND, was introduced. Security vulnerabilities include cache poisoning, client flooding, and dynamic update vulnerabilities. Efforts are made to improve DNS security.
The document discusses the Domain Name System (DNS), which maps host names to their corresponding IP addresses. DNS is an internet directory service that acts as a client-server application to provide name mapping, as IP addresses are difficult to remember and can change. Historically, name mapping was done using a host file on each computer, but as the internet grew this became impractical, leading to the distributed DNS system with a hierarchy of root, top-level domain, and authoritative name servers. DNS supports two types of queries - recursive queries where a server resolves a query itself, and iterative queries where a server refers the query to another name server.
The Domain Name System (DNS) is a hierarchical decentralized naming system for computers, services, or any resource connected to the Internet or a private network. It associates various information with domain names assigned to each of the participating entities. Most prominently, it translates more readily memorized domain names to the numerical IP addresses needed for the purpose of locating and identifying computer services and devices with the underlying network protocols. By providing a worldwide, distributed directory service, the Domain Name System is an essential component of the functionality of the Internet.
The document discusses DNS (Domain Name System) servers and how they work. It explains that DNS servers translate human-readable domain names to machine-readable IP addresses in 7 steps: 1) A request is made, 2) recursive DNS servers are queried, 3) root nameservers are queried, 4) TLD nameservers are queried, 5) authoritative nameservers are queried, 6) the IP address record is retrieved, and 7) the answer is received. DNS servers act like a phone book to lookup domain names and allow the internet to function by linking names to IP addresses.
The DNS name resolution process involves a DNS server checking its local cache, hosts file, and forwarding the request to higher-level DNS servers if the address is not found. As a last resort, the root hints file is used to forward the request to a root DNS server, which will then direct the request to a top-level domain server that can provide the IP address. DNS translates hostnames to IP addresses through a hierarchical system of root, top-level, and authoritative DNS servers.
The document summarizes the Domain Name System (DNS), which maps domain names to IP addresses. It describes how DNS evolved from a single host file to a hierarchical, decentralized system. DNS uses a tree-like structure with top-level domains like .edu or .com at the top. It assigns authoritative name servers to each domain to answer queries and cache previous responses to improve efficiency.
This document discusses IP addresses, DNS, DHCP, and related networking concepts. It defines an IP address as a unique number assigned to devices on a network that allows them to be identified and located. It describes IPv4 and IPv6 address standards and how network and host IDs are defined for different address classes. It also explains loopback addresses, APIPA addresses, DNS and how it translates names to addresses, and DHCP and how it dynamically assigns IP addresses and configuration information to devices on a network.
The document discusses DNS (Domain Name System) records. It explains that DNS is a hierarchical naming system that maps hostnames to IP addresses. DNS records are the basic data elements that allow DNS servers to perform this mapping. The document describes several important DNS record types including A records, which map hostnames to IPv4 addresses; AAAA records, which map to IPv6 addresses; CNAME records, which map aliases to hostnames; and MX records, which specify mail servers for a domain. It also briefly mentions SOA, PTR, and SRV records along with sources for further information on DNS records.
DNS allows users to reference computer names via symbolic names like domain names instead of IP addresses. It works by translating these symbolic names to their associated IP addresses. DNS uses a hierarchical and distributed database across interconnected name servers to provide a global directory service for name resolution on the internet.
The memory system is divided into three main parts: TPA, system area, and XMS. The first 1MB of memory is called real or conventional memory. It is divided into TPA (640KB) and system area (384KB). TPA holds the operating system, active programs, and inactive programs. The system area is smaller and contains programs like video control programs in ROM/flash. Memory above 1MB is available for use by expanded memory systems.
This document discusses the Domain Name System (DNS) and its objectives, need, services, and workings. The key points are:
DNS provides hostname to IP address translation, allowing humans to use hostnames while computers use IP addresses. It is a distributed database system with local, root, and authoritative name servers. DNS also provides host aliasing, mail server aliasing, and load distribution services. Resource records containing hostname mappings are stored across name servers, with caching to improve efficiency.
The document discusses India's tourism industry and the Ministry of Tourism's role in regulating it. It outlines the ministry's hotel classification system of 1-5 star ratings and heritage categories. It also discusses the ministry's approval and classification of travel agents, tour operators, adventure tour operators, and transport operators. Various tourism products and the seven pillars of tourism are briefly mentioned as well.
The document discusses inheritance in C++. Inheritance allows new classes called derived classes to be created from existing classes called base classes. This allows code reuse and for common attributes and operations to be defined in the base class and shared by derived classes. Different types of inheritance are described including single, multi-level, multiple, hierarchical and hybrid inheritance with examples provided. Access control and visibility modes like public, private and protected inheritance are also explained.
This document outlines the agenda and functions for a menu driven program in ALP to perform file handling operations. It discusses using INT 21H functions to get the system time and date, create, open, close, read, write, and delete files. It provides code snippets for calling each of the file handling functions to create, write to, read from, delete files, and display the system time and date.
This document discusses the greedy algorithm approach for finding minimum spanning trees. It explains that greedy algorithms make locally optimal choices at each step to arrive at a global solution. Kruskal's algorithm is presented as an example greedy algorithm for finding minimum spanning trees. It works by sorting the edges by weight and then adding edges one by one if they do not form cycles. While greedy algorithms are faster, they do not always find the true optimal solution.
Dhaval Kapil presented on DNS security. He discussed how DNS works and its flaws due to a lack of security in its original design. This allowed various threats to emerge like zone file compromise, DNS amplification attacks, and cache poisoning. To mitigate these threats, extensions like DNSSEC were developed to authenticate DNS responses and ensure integrity, though adoption remains limited.
The document compares Java bytecode and the Common Intermediate Language (CIL) used in .NET. Both Java and .NET compile source code to an intermediate bytecode - Java bytecode and CIL respectively. These bytecodes are then executed by their virtual machines - the Java Virtual Machine (JVM) for Java bytecode and the Common Language Runtime (CLR) for CIL. The document provides details on the structure and purpose of bytecode, CIL, the JVM, and CLR.
This document discusses minimum spanning trees. It defines a minimum spanning tree as a spanning tree of a connected, undirected graph that has a minimum total cost among all spanning trees of that graph. The document provides properties of minimum spanning trees, including that they are acyclic, connect all vertices, and have n-1 edges for a graph with n vertices. Applications of minimum spanning trees mentioned include communication networks, power grids, and laying telephone wires to minimize total length.
This document provides an introduction to SNMP (Simple Network Management Protocol). It describes the basic concepts of SNMP including the management components of managers, agents, MIB (Management Information Base) and network management protocol. It also covers SNMP architectural model, services, PDUs (protocol data units) and standards. Key terms like OID (object identifier), data types and MIB structure are defined.
A demux is a digital switch that takes a single input signal and distributes it to multiple outputs based on select lines. It has one input and multiple outputs, with the select lines determining which output the input is routed to. Common demux configurations include 1-to-2, 1-to-4, 1-to-8, and 1-to-16 depending on the number of select lines. A typical application is routing a single data source like a laser printer to multiple destinations like a fax machine, inkjet printer, or plotter.
A graph consists of vertices and edges, where vertices represent entities and edges represent relationships between vertices. Graphs can be represented sequentially using matrices like adjacency and incidence matrices, or linked using data structures like adjacency lists. Adjacency matrices allow fast addition/removal of edges but use more memory, while adjacency lists use less memory but are slower to modify. The best representation depends on whether the graph is dense or sparse.
The document discusses SNMP (Simple Network Management Protocol). It provides a high-level overview of SNMP including its history, versions, components like SMI and MIB, and basic operations. SNMP allows network devices to be monitored and managed remotely. It uses a client/server model where a manager communicates with agents running on devices using SNMP messages to get/set variable values defined in MIBs.
Templates allow functions and classes to operate on generic types in C++. There are two types of templates: class templates and function templates. Function templates are functions that can operate on generic types, allowing code to be reused for multiple types without rewriting. Template parameters allow types to be passed to templates, similar to how regular parameters pass values. When a class, function or static member is generated from a template, it is called template instantiation.
The document discusses graphs and their applications. It defines key graph terms like vertices, edges, directed/undirected graphs, paths, cycles, etc. It then describes algorithms for finding minimum spanning trees, Eulerian cycles, Hamiltonian paths, and approximations for the traveling salesman problem. Examples are provided to illustrate minimum spanning tree and Christofide's algorithms for TSP.
SNMP is a set of protocols for managing network devices. It uses a manager-agent model where a manager controls and monitors agents, usually routers. SNMP relies on SMI to define object naming and types and MIB to create a collection of named objects and their relationships. Objects are given OIDs starting with 1.3.6.1.2. SNMP versions 1 and 2c provide limited security while version 3 adds authentication and encryption. SNMP uses community strings for authentication in versions 1 and 2c and username/password in version 3. Common packet types include get, set, and trap requests.
The document discusses the 8051 microcontroller, its features, and applications. It provides details on the 8051's architecture including its CPU, memory blocks, I/O ports, timers/counters, and serial communication capabilities. It describes the 8051's registers including TMOD and TCON for timer control. The document also covers the 8051's memory mapping and provides many examples of how 8051 microcontrollers are used in applications like cell phones, appliances, industrial systems, and more.
This document provides an overview of UNIX memory management. It discusses the history of UNIX and how it evolved from earlier systems like Multics. It describes swapping as an early technique for virtual memory management in UNIX and how demand paging was later introduced. Key concepts discussed include page tables, page replacement algorithms like two-handed clock, and the kernel memory allocator.
Talk by Jonathan Oxer at Linux Users Victoria in April 2007 about how DNS works. Covers authoritative and recursive DNS, delegation, and attack vectors including cache poisoning and DNS forgery. More information at http://jon.oxer.com.au/talks/id/66
The Domain Name System (DNS) provides translation between human-readable domain names and machine-readable IP addresses. DNS works like a phone book, allowing users to look up IP addresses using easier to remember domain names. DNS has a hierarchical structure with top-level domains at the root and subordinate domains below. DNS servers store and serve DNS records to resolve domain names to IP addresses through either iterative or recursive queries. Authoritative DNS servers maintain definitive records for their registered domains.
1. DNS resolves computer names to IP addresses through a hierarchical system of DNS servers and zones.
2. DNS servers contain DNS databases and resolve queries by providing the requested information directly or referring to other servers.
3. A DNS zone is a contiguous portion of the DNS namespace for which a DNS server is authoritative, containing domain records in zone files.
The document provides an overview of the Domain Name System (DNS) including:
- DNS is an internet directory service that maps hostnames to IP addresses through a hierarchical domain name space.
- The top of the DNS naming hierarchy is managed by ICANN and includes over 250 top-level domains like .com, .edu, .gov, and country-specific domains.
- DNS resource records like A, MX, NS, and CNAME contain information mapped to domain names, such as IP addresses, mail servers, name servers, and aliases. This information is stored in DNS databases distributed across name servers.
The Domain Name System (DNS) is a hierarchical distributed naming system that translates human-friendly domain names like www.google.com to IP addresses like 192.0.32.10. DNS serves as the phone book of the internet by mapping names to addresses. It uses a client-server query/response system to look up names and return addresses between DNS servers and clients.
DNS is used to resolve hostnames to IP addresses. It works on port 53 and uses a hierarchical structure with roots, top-level domains, and second-level domains. DHCP is used to dynamically assign IP addresses to clients on a network. It uses a four-step process (discover, offer, request, acknowledgement) to lease an IP address to a client for a specified duration. Both DNS and DHCP are important for networking and name resolution in Windows environments.
The document discusses the Domain Name System (DNS) which works to match domain names to IP addresses and vice versa. It describes how DNS was developed in the 1980s as the number of internet hosts grew dramatically. It also discusses DNS structure, name resolution methods, DNS queries, name server types, designing a good DNS, and DNS security issues. DNS is a critical service that binds internet servers worldwide by providing a distributed database for resolving domain names to IP addresses.
The document provides an overview of the Domain Name System (DNS) by discussing its history, components, and purpose. DNS evolved from a centralized hosts file to a distributed database to map domain names to IP addresses as the internet grew. It has three main components: the name space which defines domain name structure, name servers which store DNS information, and resolvers which query name servers to translate names to addresses. DNS provides a global, scalable, and reliable system through data replication and distribution across multiple name servers to lookup information and translate domain names.
This document discusses DNS (Domain Name System) and how it relates to censorship. It notes that DNS is commonly targeted by censors because it lacks cryptographic integrity, DNSSEC is not widely implemented, and cached DNS data can persist. It describes how censors can block DNS names by pressuring domain name registrars or Internet service providers to change DNS records, effectively blocking access to certain websites indefinitely.
The document discusses the Domain Name System (DNS) which maps human-readable domain names to IP addresses. DNS uses a hierarchical domain name space and resource records stored in name servers. When an application needs to resolve a name to an IP address, it queries a local DNS server which communicates with other name servers until the correct IP address is found. This recursive query process uses the DNS protocol over UDP port 53. DNS was developed to make managing Internet addresses easier as the number of hosts grew.
The document discusses the Domain Name System (DNS), which maps human-readable domain names to IP addresses. DNS uses a hierarchical, domain-based naming scheme stored in a distributed database across multiple name servers. When a domain name is queried, DNS performs a recursive lookup by querying name servers at higher levels until it reaches an authoritative name server that can provide the IP address associated with the domain name. Caching of responses improves performance by avoiding unnecessary lookups.
This document provides an overview of the Domain Name System (DNS) in several paragraphs. It begins with an introduction to DNS as a large distributed database that contains domain names and IP addresses. It then discusses the history of DNS and how it evolved from a centralized hosts file to a distributed system. The remainder of the document describes the key components of DNS including the name space, resolvers, name servers, and explains why DNS is needed by covering aspects like scalability, reliability, and dynamic updates.
The document discusses Internet addressing and protocols. It defines an IP address as a unique number that identifies each device connected to the Internet. An IP address consists of four groups of numbers separated by periods between 0-255. While computers use binary IP addresses, they are written in "dotted decimal" format for humans. Domain names provide an easy text alternative to numeric IP addresses. The TCP/IP protocol defines how data is broken into packets and routed across networks using IP addresses.
The document discusses the Domain Name System (DNS) and how it works. It covers DNS zones, forward and reverse lookups, forwarding, and delegation. DNS associates domain names with IP addresses and other information to direct internet traffic. It functions like a phone book to translate human-readable names to computer-readable IP addresses. DNS is hierarchical, with the domain name space divided into zones served by authoritative nameservers.
This document provides an overview of the Domain Name System (DNS) and discusses some of its security and censorship implications. It begins with an introduction to DNS basics like its hierarchical structure and mapping of domain names to IP addresses. It then covers security issues such as DNS spoofing, cache poisoning, and reflection attacks. The document also discusses how DNS is used for censorship through blocking domain name resolutions or injecting false DNS responses. Overall, the document provides a high-level tour of the DNS system and some of the ways it can be exploited or manipulated for malicious purposes.
The document discusses the Domain Name System (DNS), including:
- DNS allows humans to use domain names to access internet resources while computers use IP addresses.
- DNS is hierarchical, distributed across servers globally, and designed for resilience and to avoid single points of failure.
- DNS works by mapping domain names to IP addresses through a hierarchy of root servers, top-level domain servers and authoritative DNS servers.
- The DNS namespace is hierarchical with top-level domains like .com and country domains, with future improvements focusing on security, IPv6 integration, and ties to directory services.
The document provides instructions on how to configure a DNS server. It begins by explaining what a DNS server is and its purpose of translating domain names to IP addresses. It then discusses IP addresses and the differences between dynamic and static IP addresses. Finally, it provides the steps to install and configure a Microsoft DNS server using DNS Manager. These include adding the DNS component in Windows and using DNS Manager to configure the server.
The application layer sits at Layer 7, the top of the Open Systems Interconnection (OSI) communications model. It ensures an application can effectively communicate with other applications on different computer systems and networks. The application layer is not an application.
The document provides an overview of the Domain Name System (DNS) and Internet Relay Chat (IRC). It defines DNS as a protocol that translates between domain names and IP addresses, allowing users to use easy-to-remember names instead of numeric addresses. It describes how DNS works by querying name servers in a hierarchical system to resolve domain names to IP addresses. The document also defines IRC as a protocol for real-time text communication over the Internet, allowing users on different systems to communicate in group channels or privately. It notes some popular IRC clients and discusses advantages like low-cost communication and disadvantages like potential for addiction or abuse.
Domain Name System (DNS) is a hierarchical distributed database that contains mappings of domain names to IP addresses. DNS allows easy to remember domain names to be used instead of hard to remember IP addresses. It works by matching domain names to IP addresses through a lookup process involving root servers, top-level domain servers and authoritative name servers. This allows computers all over the world to communicate with each other using domain names.
The document discusses the Domain Name System (DNS) and how it works. It provides the following key points:
- DNS translates domain names that are easy for humans to remember (e.g. www.google.com) into IP addresses that computers use to locate websites and resources.
- DNS operates as a hierarchical and decentralized naming system, with top-level domains (TLDs) like .com at the top, and second-level and third-level domains further specifying organizations and websites.
- DNS servers store records mapping domain names to IP addresses, and work together to direct queries to the authoritative name server to resolve a requested domain name into its corresponding IP address.
This document discusses the diamond problem that can occur with multiple inheritance in C++. Specifically, it shows an example where a class "four" inherits from classes "two" and "three", which both inherit from class "one". This results in two copies of the base class "one" being present in objects of class "four", leading to ambiguity when trying to access attributes from the base class. The document presents two ways to resolve this issue: 1) manual selection using scope resolution to specify which attribute to access, and 2) making the inheritance of the base class "one" virtual in classes "two" and "three", which ensures only one copy of the base class exists in class "four" objects. The virtual
The document discusses India's Unique Identification (UID) project and the Unique Identification Authority of India (UIDAI). It describes the purpose of UIDAI as providing a unique identification number to all Indian residents. It outlines the enrollment and authentication processes and discusses the various agencies, technologies, and challenges involved in implementing the UID system on a large scale. Key risks discussed include issues relating to adoption, privacy/security of biometric data, and ensuring the system's long-term sustainability.
The document discusses key concepts in estimation theory including point estimation, interval estimation, and sample size determination. Point estimation involves calculating a single value to estimate an unknown population parameter. Interval estimation provides a range of values that the population parameter is likely to fall within. Sample size is important for balancing statistical power and cost; larger samples improve precision but also increase expenses. The document outlines methods for constructing confidence intervals for means, proportions, and differences between parameters.
The document discusses strings in C and common string functions. It defines a string as an array of characters terminated by a null character. It describes two ways to use strings - with a character array or string pointer. It then explains functions such as strcpy(), strcat(), strcmp() that copy, append, or compare strings. Other functions like memcpy(), memcmp() operate on a specified number of characters rather than null-terminated strings.
Statistical Quality Control (SQC) is used to evaluate organizational quality through statistical tools. SQC can be classified into descriptive statistics, statistical process control, and acceptance sampling. Descriptive statistics describe quality characteristics and relationships through measures like the mean and standard deviation. Statistical process control uses random sampling to determine if a process is producing products within a predetermined range. Acceptance sampling involves random inspection of samples to determine if an entire lot should be accepted or rejected. Control charts graphically show whether sample data falls within the normal variation limits.
The document discusses implementation of stacks. It describes stacks as linear data structures that follow LIFO principles. Key stack operations like push and pop are outlined. Stacks are often implemented using arrays or linked lists. Examples of stack applications include recursion handling, expression evaluation, parenthesis checking, and backtracking problems. Conversion from infix to postfix notation using a stack is also demonstrated.
Stack is a last-in, first-out (LIFO) data structure where elements are inserted and removed from the top. Pushing adds an element to the top of the stack, while popping removes the top element. A stack overflow occurs when pushing to a full stack, while a stack underflow happens when popping an empty stack. Stack applications include system startup/shutdown processes, function calling where the last function called is the first to return, and argument passing in C where arguments are pushed right-to-left and popped left-to-right.
SPSS is a statistical software package used for data management and analysis. It can import data from various file formats, perform complex statistical analyses and generate reports, tables, and graphs. Some key features include an easy to use interface, robust statistical procedures, and the ability to work with different operating systems. While powerful and popular, SPSS is also expensive and less flexible than open-source alternatives like R for advanced or custom analyses.
The document discusses various data structures for representing sets and algorithms for performing set operations on those data structures. It describes representing sets as linked lists, trees, hash tables, and bit vectors. For linked lists, it provides algorithms for union, intersection, difference, equality testing, and other set operations. It also discusses how bit vectors can be used to efficiently represent the presence or absence of elements in a set and perform operations using bitwise logic.
Sets are collections of unique elements that do not allow repetition. Elements must satisfy membership rules to be included in a set. Common set operations include union, intersection, difference and subset testing. Sets can be mutable, allowing addition and removal of elements, or immutable. Hash functions are used to map elements to locations in hash tables, enabling fast set operations on large collections. Spelling checkers use hash tables to implement sets and check dictionary words against input words.
This document discusses real-time operating systems (RTOS). It defines RTOS as operating systems that are able to respond to inputs immediately within a specified time delay. It compares RTOS to general operating systems and discusses the types, characteristics, functions, and applications of RTOS. Examples of RTOS like VxWorks are provided. The key functions of an RTOS include task management, scheduling, resource allocation, and interrupt handling. RTOS are widely used in applications that require deterministic responses like avionics, medical devices, industrial automation, and more.
The document discusses parsing in compilers. It defines parsing as the second stage after lexical analysis, where a parser checks if the stream of tokens from the lexical analyzer is grammatically correct by generating a parse tree. The fundamental theory behind parsing is context-free grammar, which is used to define languages and check parsing. The document then discusses context-free grammars, parse trees, ambiguity, and provides examples of grammars for Boolean expressions to illustrate parsing concepts.
This document discusses interrupts and the mouse on the 8086 CPU. It describes how interrupts work on the 8086, including hardware, software, and interrupt service routines. It explains the fetch-execute cycle of the CPU and the interrupt sequence. It then covers mouse features like pixels and the mouse pointer. It discusses the interrupt vector table format and how mouse functions like initializing, displaying, hiding the cursor, and getting button/position information are accessed through interrupt 33h.
The motherboard is the central circuit board in a computer that connects the various components like the CPU, memory, storage, and peripherals. It provides the electrical pathways allowing these components to communicate with each other. Over time, more functions have been integrated onto motherboards, from basic components in early computers to modern boards that support complex graphics, audio, and networking. The motherboard contains the BIOS, chipset that directs data flow, and expansion slots to connect additional components. Common motherboard failures include catastrophic failures during early use, intermittent component failures, and difficult to diagnose issues causing crashes or reboots.
This document provides additional information about LEX and describes several LEX patterns, variables, functions, start conditions, and examples. It explains that LEX is used for text processing and scanner generation. It also describes pattern matching symbols, special directives like ECHO and REJECT, variables like yytext, and functions like yylex(), yyless(), and yywrap(). Examples are provided for multi-file scanning, counting character sequences, and generating HTML.
A multimedia database management system (MMDBMS) stores and manages multimedia data like text, images, audio, and video. Multimedia data can be stored in three parts - raw data, registering data, and descriptive data. Registering data provides interpretation information, descriptive data describes content and structure, and raw data is the unformatted information content like pixels. An MMDBMS allows input, output, modification, deletion, comparison, and evaluation operations on different multimedia data types. MMDBMS design can be based on object-oriented or entity-relationship database models.
This document discusses different techniques for merging files in revision control systems. It begins by introducing the concept of merging as reconciling multiple changes made to files. It then discusses external sorting techniques that can handle large amounts of data. The main merging techniques covered are two-way merging, three-way merging, and k-way merging. Two-way merging considers differences between two files alone, while three-way merging also looks at the original parent file. Three-way merging is generally more reliable with less need for user intervention. K-way merging uses a tournament sort algorithm to merge an arbitrary number of files.
This document discusses memory-based database management systems (MDBMS). Key points include:
- An MDBMS stores the database in main memory rather than disk storage for faster access speed. However, data is transient and could be lost if power is lost.
- MDBMS are well-suited for applications with frequent data reads, shared databases with many users, or where performance is critical. They are less suitable when data persistence is required.
- Sybase implemented an MDBMS that uses memory as a virtual disk volume, retaining the SQL interface. Transactions are stored in a transfer table then committed to the original disk-based database.
This document provides an introduction to the linker and linking process. It discusses how a linker binds external references in object files to the correct memory addresses. The key steps are:
1. The linker takes object files generated by the compiler and combines them into a single executable.
2. It performs relocation which modifies the object code to reflect the actual memory addresses assigned during linking.
3. The linking process resolves symbols and allows references between separate object programs to be combined into a fully linked executable.
This document provides an example of simple linear regression with one independent variable. It explains that linear regression finds the line of best fit by estimating values for the slope (b1) and y-intercept (b0) that minimize the sum of the squared errors between the observed data points and the regression line. It provides the formulas for calculating the least squares estimates of b1 and b0. The document includes a table of temperature and sales data and a corresponding scatter plot as an example of simple linear regression analysis.
Performance Budgets for the Real World by Tammy EvertsScyllaDB
Performance budgets have been around for more than ten years. Over those years, we’ve learned a lot about what works, what doesn’t, and what we need to improve. In this session, Tammy revisits old assumptions about performance budgets and offers some new best practices. Topics include:
• Understanding performance budgets vs. performance goals
• Aligning budgets with user experience
• Pros and cons of Core Web Vitals
• How to stay on top of your budgets to fight regressions
MYIR Product Brochure - A Global Provider of Embedded SOMs & SolutionsLinda Zhang
This brochure gives introduction of MYIR Electronics company and MYIR's products and services.
MYIR Electronics Limited (MYIR for short), established in 2011, is a global provider of embedded System-On-Modules (SOMs) and
comprehensive solutions based on various architectures such as ARM, FPGA, RISC-V, and AI. We cater to customers' needs for large-scale production, offering customized design, industry-specific application solutions, and one-stop OEM services.
MYIR, recognized as a national high-tech enterprise, is also listed among the "Specialized
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Transcript: Details of description part II: Describing images in practice - T...BookNet Canada
This presentation explores the practical application of image description techniques. Familiar guidelines will be demonstrated in practice, and descriptions will be developed “live”! If you have learned a lot about the theory of image description techniques but want to feel more confident putting them into practice, this is the presentation for you. There will be useful, actionable information for everyone, whether you are working with authors, colleagues, alone, or leveraging AI as a collaborator.
Link to presentation recording and slides: https://bnctechforum.ca/sessions/details-of-description-part-ii-describing-images-in-practice/
Presented by BookNet Canada on June 25, 2024, with support from the Department of Canadian Heritage.
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2. What is DNS ? Resolving
Why DNS ? Message format
Working of DNS. ER diagram
DNS Hierarchy DNS DB
Features Summary…
Intro to IP
2
3. The term DNS stands for “domain name system.”
DNS created in 1983 by Paul Mockapetris .
A globally distributed, scalable, reliable, dynamic database
It translates human-friendly website addresses into computer-friendly IP
addresses and viceversa.
3
4. the Internet is based on IP addresses, not domain names.
IP Addresses are convinient for computers
(IP address includes information used for routing.)
IP addresses are tough for humans to remember.
IP addresses are impossible to guess.
Domain names comprise a hierarchy so that names are unique, easy to
remember.
4
5. A domain is an arrangement of client and server computers that act together
as one system.
A domain name is key to doing just about anything on the Internet, from
setting up a web site to sending and receiving email to building an online
store.
A domain name is the sequence of labels from a node to the root, separated
by dots (“.”s), read left to right
The name space has a maximum depth of 127 levels
Domain names are limited to 255 characters in length
5
6. Every interface on an internet must have a unique address called IP address.
These addresses are 32 –bit numbers, normally written as four decimal
numbers,one for each byte of the address.
This is called dotted-decimal notation.
6
8. Every machine has a unique identification in network. That will used to
identify the specific system in the network. That unique identifier is called
The IP address is basically the address that distinguishes where you want
tosend information to, and from where the information comes.
There simply has to be a way to distinguish with which of the millions of
computers in the world you want to communicate.
The IP address is represented by the dotted values. Eg 172.16.35.254.
8
9. The IP(internet Protocol) is available in two versions,
There are,
IPv4(Internet Protocol version 4)
IPv6(Internet Protocol version 6)
IPv4 is wisely using internet protocol. Ipv6 is upgraded version of IPv4.
9
10. The IPv4 addresses are 4 byte(32 bits) in length.
The IPv4 addresses denoted with the dotted numbers
The IP address is denoted as “n.n.n.n”. Here „n‟ is a decimal value. The n
value range is 0 to 255.
IPv4 is wisely using Internet Protocol.
The IPv4 have the internet number as well as the host number.
Eg:
172.16.35.254
10
11. IPv6(Internet Protocol version 6) is a upgraded version of the IPv4.
IPv6 addressing is denoted with the 8 sets of 4 hexadecimal values, 16 bits
in each sets. Each set is separated with the colon(:).
IPv6 address is denoted as “xxxx:xxxx:xxxx:xxxx:xxxx:xxxx:xxxx:xxxx” (
‟x‟ would be hexadecimal value).
The hexadecimal values can be represented in the Upper-case or Lower case
for the number „A-F‟. A leading zero in a set of numbers can be omitted
ABC:567:0:8888:0:9999:1111:0
abc:567:8888:0:9999:1111:0
The IPv6 is not using wisely.
11
12. The DNS(Domain Name Server) is a directory lookup service that provides
a mapping between the name of the host on the internet and its numerical
address.
Four elements comprise
Domain Name Space
DNS database
Name servers
Resolvers
12
13. It is 32 bit address provides uniquely identifying device.
It has two components
Network number
Host address
Domain refers to a group of hosts that are administrative control.
Domains are organizes hierarchically, so that the domain has sub routines.
13
14. DNS is a hierarchical system.
DNS organizes all registered names in a tree structure.
At the base or root of the tree are a group of top-level domains including
familiar names like com, org, and edu.
Below this level are the second-level registered domains such as about.com
The tree can have 128 levels: level 0 (root) to level 127.
14
17. The DNS database contains a list of registered domain names.
The top level of the DNS hierarchy, also called the root level
It is maintained by a set of 13 servers called root name servers.
Those servers in turn knows all the TLDs which contain the same vital
information
They are coordinated by ICANN and are distributed around the world.
17
19. ICANN
The Internet Corporation for Assigned
Names and Numbers
The headquarters is in Marina del Rey,
California, United States,
It was created on September 18, 1998,and
incorporated on September 30, 1998.
19
20. To oversee administer Internet resources including
Addresses
Delegating blocks of addresses to the regional registries.
Protocol identifiers
Allocating port numbers, etc.
Names
Administration of the root zone file.
Oversight of the operation of the root name servers.
20
21. SCALABILITY
No limit to the size of the database
One server has over 20,000,000 names
Not a particularly good idea
No limit to the number of queries
24,000 queries per second handled easily
Queries distributed among masters, slaves, and caches
21
22. RELIABILITY
Data is replicated
Data from master is copied to multiple slaves
Clients can query
Master server
Any of the copies at slave servers
Clients will typically query local caches
DNS protocols can use either UDP or TCP
If UDP, DNS protocol handles retransmission, sequencing, etc.
22
23. DYNAMICITY
Database can be updated dynamically
Add/delete/modify of any record
Modification of the master database triggers replication
Only master can be dynamically updated
Creates a single point of failure
23
24. RESOLUTION
Mapping a name to an address or an address to a name is called name-
address resolution.
Types of Resolution:-
Recursive Resolution
Iterative Resolution
24
28. In the example a client somewhere on the Internet needs the IP address of
www.google.com The following events take place:
1.The client contacts NameServer1 with a recursive query for
www.google.com. The server must now return either the answer or an
error message.
2.NameServer1 checks its cache and zones for the answer, but does
not find it, so it contacts a server authoritative for the Internet (that is, a
root server ) with an iterative query for www.google.com.
3.The server at the root of the Internet does not know the answer, so
it responds with a referral to a server authoritative for the .com domain.
28
29. 4.NameServer1 contacts a server authoritative for the .com domain with an
iterative query for www.google.com.
5.The server authoritative for the .com domain does not know the exact
answer, so it responds with a referral to a server authoritative for the google.com
domain.
6.NameServer1 contacts the server authoritative for the google.com
domain with an iterative query for www.google.com.
7.The server authoritative for the google.com domain does know the
answer. It responds with the requested IP address.
8.NameServer1 responds to the client query with the IP address for
www.google.com.
29
30. DNS MESSAGES
The DNS query message consists of a header and question
records; the DNS response message consists of a header, question records,
answer records, authoritative records, and additional records.
30
33. Section Name Description
Contains fields that describe the
type of message and provide
important information about it.
Header
Also contains fields that indicate
the number of entries in the other
sections of the message.
Carries one or more “questions”,
that is, queries for information
Question
being sent to a DNS name
server.
33
34. Section Name Description
Carries one or more resource
records that answer the
Answer
question(s) indicated in the
Question section above.
Contains one or more resource
records that point to
Authority authoritative name servers that
can be used to continue the
resolution process.
Conveys one or more resource
records that contain additional
information related to the
Additional
query that is not strictly
necessary to answer the queries
(questions) in the message.
34
35. The system which is in network request a web page to it‟s local server.
The local DNS of that server maintain the details of the local clients
connected to it.
From that server the page request forwarded to the DNS of the web content.
The request or the query for the particular page is in the name of that local
server.
The query first processed by the resolver, it and then forward to the SLAVE
NAME SERVER. If the domain name is found in that it will return the IP
address to the requested resolver.
35
36. If the domain name is not found in the particular slave domain it and then
forward the detail of the requested resolver and the domain name to the
higher name server.
The resolver details should be maintained in each level of name server if
that regarding to it‟s own zone.
The several zones are there under one primary name server. The primary
name server of zones may be slave name server of another primary name
server.
Each and every zone has it‟s unique salve name server.
36
37. The IP address of the requested page can be directly forwarded from the
current name server level., or the address should be returned through the
backward direction in the path the request came.
The details of the requested result stored in slave name server. If the IP
address in found then the IP address and the domain name stored. Otherwise
the negative result be stored. This is caching.
The first thing the slave name server has to do is search the particular
domain name in it‟s cached detail. If it is not found then it forward the
request to the higher level NS.
37
39. It is based on hierarchical database containing Resourses Records(RRs) that
includes IP address and other information about hosts.
Key features:
Variable-depth hierarchy for names
Distributed Database
Distribution controlled by the database.
39
41. Name Servers:
These are server programs that hols information about a protion of the
domain name tree structure and the associated RRs.
Resolver.
These are programs that extract information from names servers in
response to client request is for an IP address corresponding to a given
domain name.
41
42. The need of DNS is demonstrated here.
Without DNS we can not imagine the internet itself.
The achievement done in the internet and web environment are the branch
from the DNS invention.
42