Tutor profile: Sudhindra S.
Subject: Python Programming
What happens when you type foo = 1,2,3,4,5 in a python interpreter? Is this a valid statement? If so, what is the data type of foo?
Python treats foo as a tuple here. When you print the output of foo, it returns (1,2,3,4,5). This is called tuple packing in Python.
What is a stored procedure?
A stored procedure is a set of pre-written, pre-compiled SQL statements which can be called from within a program.
Subject: Computer Networking
What happens when you type www.google.com in your browser?
Just after hitting the Enter key, the browser now has the following information available in the URL. 1. *http* which is the protocol 2. /* which is the resource to be fetched Then the browser proceeds to parse the URL checking for non-ASCII characters, etc. After that the browser checks it's HSTS (HTTP Strict Transport Security) list. This is basically a list of websites that have requested that they be contacted with HTTPS only. If the website is present in the list, which in our case is, then the request will be made via HTTPS from now on. Next step is the DNS lookup, the browser checks if the domain is available in it's cache, if not found the browser requests the hostname by making an OS call, this is to check if the hostname can be resolved via the local /etc/hosts file before attempting to request it from the DNS server. If the OS does not have it cached nor can find it in the hosts file then it makes a request to the DNS server configured in the network stack. If the local/ISP DNS cannot find the host entry, then a recursive search is made that flows up the list of DNS servers until the SOA is really reached. The answer is then returned if found. Once the browser receives the IP address of google.com, it will open a socket with the IP address and port 443 (HTTPS) by making a system call. Then after a successful TLS handshake, a secure connection is established between the browser and Google. The request and headers are then transmitted by the browser and upon receiving a 200 OK response followed by the html content from Google, the browsers renders the html, css, js, fetches any external images, etc, and then displays it to the user.
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