OCR H446/01 – 1.3 Exchanging data

Posted on by Administrator Posted in H446 - Computer Science A Level (OCR)
1.3 Exchanging data - Overview / Checklist
1.3.1 Compression, Encryption and Hashing
(a) Lossy vs Lossless compression.
(b) Run length encoding and dictionary coding for lossless compression.
(c) Symmetric and asymmetric encryption.
(d) Different uses of hashing
1.3.2 Databases
(a) Relational database, flat file, primary key, foreign key, secondary key, entity relationship modelling, normalisation and indexing.
(b) Methods of capturing, selecting, managing and exchanging data.
(c) Normalisation to 3NF.
(d) SQL – Interpret and modify.
(e) Referential integrity.
(f) Transaction processing, ACID (Atomicity, Consistency, Isolation, Durability), record locking and redundancy.
1.3.3 Networks
(a) Characteristics of networks and the importance of protocols and standards.
(b) The internet structure:

    The TCP/IP Stack.
    DNS
    Protocol layering.
    LANs and WANs.
    Packet and circuit switching.

(c) Network security and threats, use of firewalls, proxies and encryption.
(d) Network hardware.
(e) Client-server and peer to peer.

1.3.4 Web Technologies
(a) HTML, CSS and JavaScript.
(b) Search engine indexing.
(c) PageRank algorithm.
(d) Server and client side processing.

Recommended Resources

1.3.1 Compression, Encryption and Hashing
Symmetric and asymmetric encryption

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Lossy and Lossless Compress

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1.3.2 Databases
Relational Databases

Relational Databases

Tables, Records & Fields A table is a collection of records. Each record is made of fields. Each field has a data type such as String/Text, Integer, Float/Real, Boolean, Date & Time, etc. Primary Keys, Foreign Keys & Relationships The … Continue reading


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Exchanging data (JSON, XML) using an API
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1.3.3 Networks

Network Design

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Small Office Network (Network Design Task) The Retro-Gaming Internet Café (Network Design Task) TCP/IP Protocols and Packet Switching The TCP/IP Stack: Layers & Protocols Daily Protocolometer IP Addresses (IPv4, IPv6), MAC addresses and URLs Network Design – Drag and Drop Computer Networks – Quiz Computer Networks – Terminology Computer Networks – Crossword Network Design – Quiz Computer Networks – Acronyms Computer Networks – Noughts and Crosses The Mesh Network Puzzle Wired and Wireless Connection Methods

1.3.4 Web Technologies

Client-Server Technologies in a Web-Based Application

If you are learning to build websites you will most likely have started learning about HTML, eventually CSS and JavaScript. These three languages are client-side languages which run on your computer through the web-browser. A website that only relies on … Continue reading


Search Engine Indexing and Page Rank Algorithm

Search Engines Indexing Search engines like Google maintain huge databases called “indexes” of all the keywords and the web addresses of pages where these keywords appear. When a web designer creates a new website they can contact the search engine … Continue reading


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HTML, CSS and JavaScript

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