Computer-science_A-level_Cie
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computers-and-components6 主题
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logic-gates-and-logic-circuits2 主题
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central-processing-unit-cpu-architecture6 主题
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assembly-language-4 主题
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bit-manipulation1 主题
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operating-systems3 主题
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language-translators2 主题
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data-security3 主题
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data-integrity1 主题
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ethics-and-ownership3 主题
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database-concepts3 主题
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database-management-systems-dbms-1 主题
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data-definition-language-ddl-and-data-manipulation-language-dml1 主题
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computational-thinking-skills1 主题
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algorithms14 主题
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data-types-and-records2 主题
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arrays2 主题
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files1 主题
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introduction-to-abstract-data-types-adt1 主题
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programming-basics1 主题
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constructs2 主题
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structured-programming1 主题
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program-development-life-cycle2 主题
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program-design-2 主题
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program-testing-and-maintenance3 主题
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user-defined-data-types1 主题
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file-organisation-and-access-3 主题
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floating-point-numbers-representation-and-manipulation3 主题
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protocols2 主题
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circuit-switching-packet-switching1 主题
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processors-parallel-processing-and-virtual-machines5 主题
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boolean-algebra-and-logic-circuits4 主题
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purposes-of-an-operating-system-os3 主题
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translation-software3 主题
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encryption-encryption-protocols-and-digital-certificates3 主题
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artificial-intelligence-ai4 主题
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recursion1 主题
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programming-paradigms4 主题
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object-oriented-programming7 主题
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file-processing-and-exception-handling2 主题
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data-representation5 主题
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multimedia3 主题
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compression2 主题
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networks-and-the-internet11 主题
protocol-examples
Standard protocols
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A protocol is a set of rules that govern communication on a network
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There are protocols for different purposes, such as:
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HTTP & HTTPS
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FTP
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POP, IMAP & SMTP
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BitTorrent
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HTTP & HTTPS
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Hypertext Transfer Protocol (HTTP) allows communication between clients and servers for website viewing
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HTTP allows clients to receive data from the sever (fetching a webpage) and send data to the server (submitting a form, uploading a file)
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HTTPS works in the same way as HTTP but with an added layer of security
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All data sent and received using HTTPS is encrypted
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HTTPS is used to protect sensitive information such as passwords, financial information and personal data

FTP
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File Transfer Protocol (FTP) allows sending and receiving files between computers
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Uploading and downloading files to/from a web server is often completed using FTP
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FTP offers greater efficiency and support for bulk transfers and large files such as resuming interrupted transfers
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FTP clients are software applications that use the FTP protocol to make the process easier for users

POP, IMAP & SMTP
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A family of protocols that handle sending and receiving of email across the internet (WAN)

SMTP
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Simple Mail Transfer Protocol (SMTP) is a protocol that allows communication between an email sender and the email server, and between different email servers using the internet
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In the diagram above, SMTP is used to transfer the senders email to their email providers server and SMTP is used to transfer the email to the recipients email server
POP
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Post Office Protocol (POP) is a protocol for downloading emails to a device from an email server
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Once the email has been retrieved it is removed from the server
IMAP
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Internet Message Access Protocol (IMAP) is a protocol for downloading emails to a device from an email server
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Once the email has been retrieved, a copy is retained on the mail server
Advantages & disadvantages of POP/IMAP
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Advantages |
Disadvantages |
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POP |
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IMAP |
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BitTorrent
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BitTorrent is a peer-to-peer (P2P) file-sharing protocol used to distribute large amounts of data efficiently across the internet
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Instead of downloading a file from a single central server, BitTorrent allows users to download pieces of the file from multiple users (peers) who already have parts of it
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This makes file sharing:
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Faster, as downloads come from many sources at once
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More efficient, as it reduces the load on any single server
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BitTorrent is often used for:
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Sharing large files, such as software, videos, or games
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Decentralised distribution, which avoids the need for central hosting
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While BitTorrent is a legal technology, it is sometimes used for sharing copyrighted content illegally, so ethical and legal use is important
Responses