Around IT in 256 seconds

Podcast for developers, testers, SREs... and their managers. I explain complex and convoluted technologies in a clear way, avoiding buzzwords and hype. Never longer than 4 minutes and 16 seconds. Because software development does not require hours of lectures, dev advocates' slide decks and hand waving. For those of you, who want to combat FOMO, while brushing your teeth. 256 seconds is plenty of time. If I can't explain something within this time frame, it's either too complex, or I don't understand it myself. By Tomasz Nurkiewicz. Java Champion, CTO, trainer, O'Reilly author, blogger

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Technologia

Odcinki od najnowszych:

#45: Node.js: running JavaScript on the server (!)
2021-06-22 00:00:00

Node.js: running JavaScript on the server (!)", "episode_description": " JavaScript language is primarily used inside your web browser. Your computer downloads a JavaScript file and executes it on your machine. But if you want to build a dynamic website, you need a server-side language. Like PHP, Java, Python, etc. Programs written in these languages handle incoming requests and produce dynamic HTML. HTML that varies, depending on the request, who is asking and what data is available in the underlying database. But for more than a decade we can also use JavaScript on the server. The same language can be used for a very different purpose. Namely, listening and handling web requests. But also implementing command-line utilities and one-off scripts. This became possible after extracting the JavaScript engine from Chrome browser. Read more: https://256.nurkiewicz.com/45 Get the new episode straight to your mailbox: https://256.nurkiewicz.com/newsletter

#44: RESTful APIs: much more than JSON over HTTP
2021-06-15 08:43:47

REST is an architectural style of communication, based on HTTP. It was proposed in the year 2000 by Roy Fielding. In his dissertation he describes the way systems should communicate, embracing fundamental features of HTTP. He puts emphasis on: statelessness, support for caching, uniform representation and self-discoverability. APIs that adhere to these priniciples are called RESTful. This academic paper is quite abstract so I’ll focus on what it means in the enterprise. Also, it’s much easier to understand what RESTful API is when contrasted to SOAP. And GraphQL released recently. Read more: https://256.nurkiewicz.com/44 Get the new episode straight to your mailbox: https://256.nurkiewicz.com/newsletter

#44: RESTful APIs: much more than JSON over HTTP
2021-06-15 08:43:47

REST is an architectural style of communication, based on HTTP. It was proposed in the year 2000 by Roy Fielding. In his dissertation he describes the way systems should communicate, embracing fundamental features of HTTP. He puts emphasis on: statelessness, support for caching, uniform representation and self-discoverability. APIs that adhere to these priniciples are called RESTful. This academic paper is quite abstract so I’ll focus on what it means in the enterprise. Also, it’s much easier to understand what RESTful API is when contrasted to SOAP. And GraphQL released recently. Read more: https://256.nurkiewicz.com/44 Get the new episode straight to your mailbox: https://256.nurkiewicz.com/newsletter

#43: Public-key cryptography: math invention that revolutionized the Internet
2021-06-08 00:00:00

Disclaimer: this podcast is not about cryptocurrencies. I despise them. Instead, we’ll talk about asymmetric encryption. One of the most wonderful math discoveries of the 20th century. Before 1970s all cryptographic algorithms were symmetric. This means that the same key must be used to encrypt and decrypt data. That sounds rather obvious. If you encrypt a file with a password, you must use the same password to decrypt it. But there’s one problem. Imagine Bob wants to e-mail an encrypted file to Alice. Sadly, Eve can read all communication between Alice and Bob. File was encrypted, so no worries? Well, it’s not only encrypted, but also worthless. Alice doesn’t have a password. And how is Bob suppose to provide that password if Eve can spy all communication channels? Read more: https://256.nurkiewicz.com/43 Get the new episode straight to your mailbox: https://256.nurkiewicz.com/newsletter

#42: Flow control and backpressure: slowing down to remain stable
2021-06-01 00:00:00

Imagine two independent systems communicating with each other. One producing data and the other consuming it. There must be some place where data is buffered. Just in case the producer generated some data but the consumer is currently busy. For example, incoming requests, messages, packets - must wait. Sooner or later, this buffer overflows and either starts dropping data or crashes altogether. Moreover, large buffers imply growing latency between production and consumption. The consumer is perceived less responsive because data waited for a long time in queue. Especially when nothing is prioritized, so first come, first served. Also known as FIFO, first in, first out. Read more: https://256.nurkiewicz.com/42 Get the new episode straight to your mailbox: https://256.nurkiewicz.com/newsletter

#41: Unicode: can you see these: Æ, 爱 and
2021-05-25 00:02:51

Computers speak bits and bytes. Numbers in general. They don’t understand images, poems and JSON. When we say “ hello ”, it needs to be encoded to numbers. Conveniently, each character becomes one number. A number can then be stored, transfered and rendered on another computer. Therefore, everyone needs to agree which numbers represent which characters. The first commonly used attempt was called ASCII. American Standard Code for Information Interchange. In short, it’s a table of 127 symbols and their respective numbers. For example, lower-case h is 104, whereas exclamation mark is 33. There’s one problem here. 127 symbols. 7 bits. Of course, it’s an American Standard. So it ingores the existence of any other country and alphabet. Read more: https://256.nurkiewicz.com/41 Get the new episode straight to your mailbox: https://256.nurkiewicz.com/newsletter

#40: Docker: more than a process, less than a VM
2021-05-18 07:30:18

When two processes run on the same machine, they are somewhat isolated. For example, they cannot read each other’s memory. However, they still share the same file system, libraries, network ports. And hardware: CPU and memory. Docker allows running processes with greater isolation on a Linux machine. Processes like: web servers, databases or web applications. Traditionally, to achieve better isolation, virtual machines were used. Virtual machine is essentially an operating system started inside of another operating system. For example, Windows running inside Linux. Typically you run a few VMs on a single host. Unfortunately, a virtual machine has an overhead. It takes several seconds to start and uses a significant amount of memory. Docker is somewhere in between. Better isolation than plain processes, but it’s not quite yet a VM. Read more: https://256.nurkiewicz.com/40 Get the new episode straight to your mailbox: https://256.nurkiewicz.com/newsletter

#39: DNS: one of the fundamental protocols of the Internet
2021-05-11 09:53:59

Domain name system (DNS for short) is one of the fundamental protocols of the Internet. In the Internet all communication is routed through IP addresses. Traditionally, these addresses consist of four numbers, like 91.198.174.192 . Each and every server, as well as your computer, is identified using such an address. But we no longer remember phone numbers, let alone IP addresses! Remembering that the aforementioned IP belongs to wikipedia.org is tedious. DNS is often compared to a global phone book. A phone book that maps easy to remember domains like wikipedia.org or gmail.com to IP addresses - usable by machines. Without DNS the Internet could technically work. Just like you could use your phone without contacts, memorizing all phone numbers. DNS servers not only free us from remembering IP addresses. They know all of them. Read more: https://256.nurkiewicz.com/39 Get the new episode straight to your mailbox: https://256.nurkiewicz.com/newsletter

#38: HTTP cookies: from saving shopping cart to online tracking
2021-03-30 09:21:10

Before we fully appreciate how important HTTP cookies are, let’s imagine the web without them. HTTP is inherently stateless. This means that the HTTP server is not allowed and not capable of storing any context between requests. It has no memory of prior questions from the same client. Contrary to stateful protocols like FTP or SSH. They have a concept of long-running session. If you change the working directory during a session, subsequent commands take that into account. This is not the case for HTTP. For example, imagine you just logged in to GMail to see the list of unread e-mails. Now you click the most important one, from the Nigerian prince . Sadly, the server has no idea you are the person who just logged in. You must log in again. And again. This is where cookies help tremendously. Read more: https://256.nurkiewicz.com/38 Get the new episode straight to your mailbox: https://256.nurkiewicz.com/newsletter

#37: Fallacies of distributed computing
2021-03-23 00:22:04

Fallacies of distributed computing are a set of myths we believe, when designing complex systems. And what is a distributed system? Well, if your application is split into hundreds of microservices, it’s distributed. Or if you have a single application, scaled horizontally to hundreds of instances. Or… If you have a monolith connecting to a database on the other node. This is a distributed system as well! OK, we have 200 seconds left and 8 fallacies to cover. Let’s go! Read more: https://256.nurkiewicz.com/37 Get the new episode straight to your mailbox: https://256.nurkiewicz.com/newsletter

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