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anyone here in 2024

Top notch content! Thank you so much for uploading this 🍀

pro tip: pretend you are Axel and pause whenever he says Axel to answer the question.

20,000 USD seems like a good price

Jakarta Server Pages (JSP; formerly JavaServer Pages)

This is really old stuff. We are in a completely different era.

This is a piece of history for the modern internet. He mentioned AWS EC2 like a VPS, 12 years have passed but the internet world has completely changed.

Where is Axel today in 2024?

Where is Axel now? We need to know!

Being a professional in this space with over 20 years of experience, this is a really good talk, covers basically most of the concerns of high performance web system design.

This is gold! thank you

Awesome 😊

This Axel guy has made this lecture unwatchable for me. I cannot hear anything he says and lose a part of the lecture all the time. The professor is also faulty. If he wants this lecture to be recorded, then he shouldn't let a guy hijack the lecture.

where is Axel now?

So if you need a resource, make sure to buy at least 2 of them

I used to be that Axel during school, now I am a foolish bum😪

Coming here from system design primer github repo. On a journey to become a senior engineer in its true sense!

Watching this lecture today. And only ques what is Axel (The Guy Who Knows Everything) doing now. 💀

🎯 Key Takeaways for quick navigation: 00:09 David *Malan introduces CS75, a course on building dynamic websites, and discusses the structure and expectations of the course.* 01:11 Malan *explores the technical process of what happens when you enter a URL, focusing on translating a site's name into an IP address and the significance of IP addresses.* 03:11 Explains *that IP addresses are 32 bits, allowing roughly 4 billion unique addresses, leading to the transition from IPv4 to IPv6, which has a 128-bit address space.* 05:29 Discusses *the Domain Name System (DNS) and its role in translating domain names into IP addresses, emphasizing the hierarchical structure of DNS servers.* 07:28 Explores *the journey of a user's request, detailing how routers help route data through the internet, culminating in the web server processing the request and sending back the webpage.* 11:39 Breaks *down a URL into its components, explaining the protocol, hostname, domain name, and path. Highlights how browsers have become more user-friendly in handling URLs.* 14:29 Discusses *the challenges of making a personal website publicly accessible, given private IP addresses in home networks, and introduces the concept of port forwarding.* 18:17 Describes *the TCP/IP stack, emphasizing TCP as the protocol for data transmission and introducing the concept of port numbers to uniquely identify services on a server.* 20:40 Using *TCP, email to Gmail can be sent via port 25, distinct from HTTP's port 80.* 21:39 Port *forwarding allows configuring home routers to direct internet traffic to a specific computer, overcoming limitations with only one public IP address.* 22:38 Port *80 is the standard for web servers, but port forwarding restrictions mean only one person behind a router can operate awebserver. Non-standard ports like 81 are possible but inconvenient.* 23:38 Standard *web ports are 80 and 443 for HTTP and HTTPS, respectively. Non-standard ports may be blocked, affecting accessibility and commercial production.* 26:02 Purchasing *domain names involves choosing registrars like Namecheap or GoDaddy. Pricing varies, and additional features like DNS control may influence the choice.* 29:45 Web *hosting involves renting server space to store website files, and many registrars also offer hosting services. The hosting company provides DNS servers associated with the domain.* 31:37 Configuring *DNS involves specifying the IP addresses of the domain's DNS servers, typically provided by the hosting company. DNS settings are updated at the registrar, linking the domain to the server's IP address.* 34:30 DNS *records include NS (Name Server) records, A (Address) records, and CNAME (Canonical Name) records. CNAME allows mapping domains to other domains, providing flexibility and abstraction.* 37:22 CNAME *records are useful for rebranding services and redirecting subdomains to other domains. MX (Mail Exchange) records specify mail servers for a domain, enabling efficient email routing.* 39:15 Developing *websites and companies require fundamental skills in web development.* 40:11 The *CS75 course covers web development in a short six-week period, focusing on dynamic websites with PHP, JavaScript, and MySQL.* 40:40 The *course is intense, and students with limited programming experience may find it challenging, with an estimated 30 hours per project.* 41:36 Prospective *students can check past semesters on cs75.tv for videos, handouts, and project details to assess their comfort level with the course.* 42:04 The *course covers HTTP, PHP, and later explores topics like security, databases, JavaScript, and scaling web servers.* 45:21 Lectures *will address common attacks on web servers and databases, emphasizing the importance of security in web development.* 46:18 The *course concludes with a focus on scaling web servers and handling increased traffic, exploring concepts like cloud computing.* 47:41 Sections *and office hours provide additional opportunities for students to delve deeper into projects, receive guidance, and seek help.* 50:04 The *course's website offers resources, including lecture videos, handouts, and a discussion tool for interaction with classmates and staff.* 51:55 Attendance *is encouraged, and for distance students, sections will be filmed and provided online, offering flexibility.* 56:04 Shared *web hosting comes with the risk of server crashes, as issues affecting one customer can impact others sharing the server.* 58:28 Virtual *Private Servers (VPS) provide more control and flexibility compared to shared hosting, allowing users to configure the server environment.* 58:56 With *a virtual private server (VPS), you can install multiple instances of operating systems on a single physical server, creating the illusion of distinct computers with separate logins and passwords.* 59:25 VPS *provides more control than shared hosting, allowing you to keep software up to date, install custom software, and have dedicated resources, reducing the risk of server-wide compromises.* 01:00:22 While *VPS offers enhanced security by limiting access, physical access to the server poses a potential risk. Assume that, besides you, at least one other person could physically access your VPS.* 01:01:47 VPS *plans often include limited storage (e.g., 20GB) and bandwidth (e.g., 200GB/month), suitable for typical websites. However, consider potential resource contention and adversarial attacks when planning usage tied to costs.* 01:04:08 In *the CS75 course, students will run their own web server, database server, and Linux environment using a virtual machine called the CS50 Appliance, which includes Apache (web server), MySQL (database software), PHP, and more.* 01:05:29 Secure *Shell (SSH) is introduced as a way to connect to remote servers securely. Students will use SSH to connect to the CS50 Appliance, mimicking the experience of hosting a website on a remote server.* 01:07:55 Basic *input mechanisms in HTML, such as text fields, password fields, checkboxes, etc., enable the creation of dynamic websites. Students are encouraged to explore these mechanisms for user interaction.* 01:13:33 Analyzing *network traffic using browser developer tools helps understand HTTP requests and parameters. A practical example involves examining the network traffic generated by a Google search, revealing URL parameters and their role in server communication.* 01:19:20 When *a browser requests assets (like images), it sends virtual envelopes with specific details. Headers in the envelope, like the user-agent, reveal information about the user's system and browser. This information can be useful for customization but may pose privacy concerns.* 01:20:18 Examining *the source of the virtual envelope reveals details such as the request path and user-agent. Knowing the user's OS and browser is often used for customization, but it's debated whether this practice is necessary and if it compromises privacy.* 01:21:46 Web *servers use headers to communicate additional information, like cookies. The user-agent header can be used for browser and OS detection, but relying on such headers has downsides, and there are alternative methods like JavaScript feature detection.* 01:23:43 The *source of the virtual envelope contains crucial information, with the first line indicating the request path. For example, Google might use a path like `/search?q=harvard` to customize results. Response headers from the server include status codes like 200 (OK) and additional details like cookies and server information.* 01:26:03 Adjusting *styles using the browser's developer toolbar allows for quick experimentation with elements on a webpage, aiding in design and alignment tweaks without modifying the server files.* 01:41:43 Implementing *a basic search engine example by constructing an HTML form and specifying method and action attributes to mimic Google's search functionality.* 01:43:39 The *lecture introduces the vulnerability of HTTP sessions to session hijacking, emphasizing the need for security precautions and responsible use.*

Amazing lecture! Great professor and engaged students. Thanks for sharing this.. still relevant in 2024

21:21

is there any chance someone can translate it into hindi language ?

thank you so much for putting this out online, it's been amazingly useful, totally relevant in 2023

The lecture is a gem

horizontal scaling (13:00 - 21:00) load balancing & caching (21:00 - 29:00) shared session state (29:00 - 34:00) RAID (36:00 - 40:00) shared storage tech (42:00) database replication (43:00) load balancing tech (44:00 - 45:00) session affinity (46:00 - 51:00) in-memory caching (59:00 - 1:00:00) data replication - active:passive (1:11:00 - 1:14:00) active:active (1:16:00 - 1:21:00) partitioning (1:21:00 - 1:34:00) data center redundancy (1:33:00 - 1:39:00) security (1:39:00 - 1:44:00) ​ @Shaoin

Amongst other things, I am fascinated that this prof knows his students' names. Well looks like it's better to know Axel's name, but otherwise it's fascinating.

What's axel doing now?

Holy moly! What a prof! Brillant explanations!

out of context but hes so cute lol

Just thought I’d mention 2010s was the best decade Jobs were plenty We had the best games Best car designs Smartphone bullshit was just starting to gain traction No “influencers” Low inflation I mean damn brings a tear to my eye hearing this guy mention 760gb SSDs… THOSE WERE THE DAYS 😢😢😢

🌟

There seems to be a mistake at 1:29:54 since master-master replication leads to the same data on both dbs and, consequently, that a user would find their info no matter what web-server they connect to.

Can anyone explain why we care if a user gets routed to the same server each time they access the domain (specifically over http)? I thought http was a stateless protocol, so no state data about the user's session would be stored on a given webserver anyways - right? Any stateful data would have to be stored in the DB (which is partitioned out from the servers).

I wish my prof was as good as him. Enjoying his lecture even after 10 years of upload.

He is such a good teacher... wow

Link to course site isn't working. Is there an updated one?

one of the best lectures I have ever attended to learn cs things

Its been 7 years for me. I loved it then and still do. The entire course launched my career!

Isaac and Axel are BOTANICS

this course found me

Man, I wonder how is Axel doing, dude was answering all the questions.

what is axile doing ? now

Detailed Summary for [CS75 (Summer 2012) Lecture 9 Scalability Harvard Web Development David Malan by Merlin [00:08] Scalability and Web Hosting - Explaining different options to deploy applications and handle traffic online, including shared web hosting and virtual private servers (VPS). - Outlining vertical scaling and horizontal scaling as ways to increase resources and handle traffic spikes, and discussing the advantages of Amazon Web Services (AWS) for automating scaling. [07:52] Horizontal scaling means using cheaper, slower machines instead of expensive, high-end ones to stay below the ceiling of what is possible - Multiple slower, cheaper machines replaced by one high-end, expensive machine for building out the topology - Using SAS, SSDs and parallel ATA for speeding up data read/write times on databases [22:24] DNS round robin can lead to uneven server load - Caching can contribute to disproportionate load on certain servers - Sophisticated load balancing approaches can mitigate this issue [30:13] Storing sessions using RAID technology can increase site performance and provide redundancy - RAID technology can be used to store session data on a file server - RAID 0 can improve performance by striping data across multiple identical hard drives, while RAID 1 mirrors data for redundancy [43:51] Load balancers can be expensive, but there are software alternatives. - Software like Haproxy can be used for load balancing. - Cookies can also be used for maintaining sticky sessions, without compromising on privacy. [50:41] Using file based caching on static content may improve performance, but sacrifices space due to redundancy - File based caching means less regeneration of content - Redundancy in basic HTML tags can lead to increased disk space usage [01:04] Using a memory engine can help implement a cache efficiently - Memory engine tables are stored in RAM and can be used to write keys and values to implement a simple cache - Archive engine tables are slower to query but get compressed automatically, making it useful for storing log files [1:11:32] Having multiple slave databases serves as a redundancy for data loss - Databases attached to a master allow for a copy of every row that's in the master database, which can be further utilized as a redundancy if one database dies - Master-master setup is another redundancy solution to keep multiple databases in sync [1:25:37] Load balancer can ensure sticky sessions with cookie-based routing - Adding a load balancer to route traffic and store session cookies can ensure sticky sessions - Multiple master databases and cross-connecting them with load balancers adds redundancy but also complexity [1:33:13 Having multiple data centers and load balancing can improve uptime and reduce failure possibilities. - Avoid creating loops in network redundancy with two switches per server/ device. - Distribute load across different data centers and use global load balancing for higher uptime.

Need to know where Axel is now

David Malan and Axel need to host a podcast

It hooked me after 10 minutes!

All of Axels answers are Axellent

very nice. I don't usually watch 1 hour+ videos on a single go, but this had me glued. Great lecture.

axel

Imagine paying tens of thousands of dollars every year to go to Harvard and listening to some dude from the audience half the time.