Category: Tech Learnings
Just a random collection of my tech learning notes
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Big Data Udemy Course Notes
Hadoop The Apache Hadoop software library is a framework that allows for the distributed processing of large data sets across clusters of computers using simple programming models. Hadoop Common: The common utilities that support the other Hadoop modules. Hadoop Distributed File System (HDFS™): A distributed file system that provides high-throughput access to application data. Hadoop…
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HTTP versions
1.0 1995 – had to establish a new connection for every request and the connection would close after it. So if a webpage had 4 images so 5 requests need to be established including for 1 for the html page.This is TCP slow start. 1.1 1995 – Till 2015 – had introduced a keep alive…
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TLS/SSL Certificate Issuance
Public Key is used to sign into something 1. Get certificate issued from CA Server asks for the public key CA. Servers send a new message which has their own public key, domain name to get a certificate from CA. This entire message is encrypted by using the public key of the CA. CA unlocks…
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CORS – Cross Origin Resource Sharing
The browser has a CORS mechanism which restricts the loading of resources from another domain. CORS defines a way in which a browser and server can interact to determine whether it is safe to allow the cross-origin request The header which controls accesses isAccess-Control-Allow-Origin So if this header is not present, the CORS request fails.…