What Are DLLs?

What are those mysterious DLL files that are omnipresent in Windows - and have often caused problems, especially in older versions?

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[unvergebeneid]

Fun fact, printer drivers are the only DLLs whose functioning directly depends on the phase of the moon and the number of black cats you recently crossed.

[QuantumQuantonium]

Might be a bit too advanced for techquikkie but a video explaining the overall structure of the windows OS (and Linux maybe as well) could be interesting. Like the kernel, registry, windows folder, COM system, dlls, services

[AshtonSnapp]

On other platforms:
- Mac: dylib (dynamic library)
- Linux: so (shared object)

[rajm]

Programs tend to fail at accessing DLLs when the function it wants to run doesn't look the same as it expects. It's function signature is different. This can be avoided with function overloads in newer versions of the DLL. This means that the old code or function signature still exists to maintain backwards compatibility while still being able to update existing DLLs. You can find dll code that goes way back to Windows 95 in Windows 10.

[cyrus]

DLL hell is something that anyone who regularly pirates games should be completely familiar with. I have so many memories of spending hours just hunting down and fixing all of the DLLs so that a pirated game works properly

[SRC]

This becomes an issue with memory integrity switched on in Windows 10/11 - some old DLLs stop functioning and need updating.

[avrahamhollander]

Not only does dynamic linking save memory compared to a statically compiled binary, but it also saves disk space for the exact same reason. Only one copy of the library for all programs.

[ThEASbO]

I'm a C++/C# dev so .dll's are really important to me. You did a good job explaining such a beast of a topic!

[billpotter]

As a mature programmer, this video tickled a happy nerve. Early PCs had so few resources compared with today. For example, the memory (usually 640KB or less, not MB) was segmented, meaning that programs could only use 64K, without jumping through major hoops. Trying to share DLLs was a horrible (and thankfully temporary) solution to the memory problem. Death to the GAC!

[gawbe]

DLL Hell is another level of tech humor.

[doriondouglas]

I remember trying to make my own mod for a game but there were very few tutorials and none explained the basic principles like how it needed to be written as a DLL to access the games engine and the games SDK, and to link it to my custom code, so I learned a lot about DLL's by figuring out how to make it work.

[magicg]

As a software engineer, I want to compliment you on how, in such a short segment, you covered this topic. Great job.

[dominikschropp]

I needed this video one week ago, as I had an issue with old testing equipment at our company using Dlls.
Great video👍

[PederLindbergMN]

I've been coding since 2010 and have never even thought about overriding a system DLL. For many years now each application either uses built in standard DLLs or provides there own in their installation directory, completely separate from the rest of the system.

[habib_khan]

Thank you for bringing such informative short videos

[The_Horse-leafs_Cabbage]

I've become weirdly familiar with DLL files, since most VSTs (music software plug-ins and synths) come in the form of.dll files.

[lordechnobas]

tldr; programs can dynamically load and unload code, allowing programs to patch vulnerabilities or change functionality by just replacing the code loaded. the code loaded is stored in a shared object (.so) on linux and a dll on windows (.dll)

[LMinett]

Well written and thoroughly explained for a general audience. Good job

[HarmonicaMustang]

I'm a sysadmin, so my focus is on making sure compatibility is maintained. I didn't have to know how DLLs work, but it's fascinating and gives me a better understanding of why problems I come across happen.

On a similar topic, you guys should talk about Group Policy. It's an essential tool to my everyday work, and even on a consumer level it lets you work around limitations in some scenarios, like modifying personalisation options on an unlicensed copy of Windows. At its core, it's a bunch of XMLs that give blueprints for modifying the registry, so it's not a terribly complicated system.

[igordasunddas]

I knew all this (obviously as a developer I should), but I love how simple and visual you explain it! Amazing work, Linus and your Team are doing!