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In this lesson, you'll learn more about Systemd UDFD.

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So when alerted by the Linux kernel, Systemd UDFD will initialize new devices.

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And this involves writing device information to slash sys so that the complete device can

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be tracked and the device parameters can be administered.

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And also creating device notes in the slash dev directory so that there is a user interface

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that allows users to communicate with the device.

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It can be convenient to track this procedure using the UDFADM monitor command.

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That will trace every single step and it will show you in detail what is going on.

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And that can be convenient to troubleshoot.

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If ever you connect a device and nothing is happening, well, UDFADM monitor is giving

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deep level insight.

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You can also get more detailed information about devices using UDFADM info.

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Minus minus name is dev note.

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As in UDFADM info, minus minus name is dev SDA.

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Let me show you.

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So to start it, I'm using UDFADM monitor.

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And there you can see that monitor will print received events for UDF and for the kernel.

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So the kernel is the actual device event.

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And UDF is related to the rule processing.

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Let's plug in USB thumb drive.

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So here you can see that a lot of output is generated.

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And if you scroll up in the output, you can see some stuff that is actually interesting.

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So it starts by the kernel that is adding a device.

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And the device was found on this specific PCI address.

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And that is resulting in UDF checking if there's any rules to be processed.

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Then a little bit further, you can see that drivers are involved, the USB storage driver.

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And this USB storage driver is implemented by the USB storage module.

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The UAS module is involved.

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And you can see that more drivers are loaded.

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And based on the presence of a new driver, additional steps can be taken.

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Then a lot later, here we can see that the block device is added, block dev SDA.

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And on the block device, we can see right here that the partition was detected.

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And the result, well, the result should be visible in LSBLK.

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LSBLK, which is list block device.

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And in this list block device, we can see that the SDA block device has successfully been added.

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Now, in these devices, there is a lot of information that is stored.

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And you can find that information using UDF ADM.

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Info, minus minus name is slash dev slash SDA1, for instance.

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And here we can see all the device parameters that have been discovered.

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And these device parameters can be used in UDF rules.

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In the next video, you'll learn a bit about UDF rules.