For 3 years, my Mac has been very, very, very (and I mean very, very, very) sluggish.
Typing on the keyboard would give me approximately 1 character per second.
Sometimes I even had to resort to using my laptop, because it was so painfully slow.
This changed recently. Not by changing to a different computer, not by re-installing the operating system (which I tried a few times, but it did not help).
-But why did it happen then ?
Well, it all started a few days ago, my ISP shut down my internet connection for maintenance. My Mac froze completely, because I had mounted a network drive, and it suddenly disappeared while I had documents open.
I could not open my programming IDE, because it remembers what files i had open in the project last time, and it kept trying to open those files that were not accessible.
After having my internet connection back a few hours later, I decided to look at my DNS setup in my D-Link DIR-655 router.
So I thought: "Something is called 'Advanced DNS', it's disabled, might be a good idea to set up some local DNS; how do I enable it ?"
I started searching for "DIR 655 Advanced DNS" and after reading about it a little, I decided that it might not be just yet.
But I did notice that D-Link had a firmware upgrade available for my router.
I decided to upgrade my firmware, because the changelog said something about a "DNS fix".
After doing so, my PowerMac has been running like if it was brand new.
So this is a practical example on why it is a good idea to use an ARM based microcontroller in a device, for instance a router:
If there is an error, you can fix it and provide firmware upgrades easily.
Of course, it's possible with other microcontrollers as well, but if you use ARM, it's even easier, because there are plenty of different MCU vendors, thus there are plenty of example-code, because each vendor provides example code for how to do things, and there's usually at least one Linux distribution available for each Cortex-A (sometimes also for Cortex-M) MCU out there.
And since there are so many Linux distributions available, there are solutions available for most problems that have been through the times.
Firmware upgrade saves you money, because you don't have to have 200 people working in your support department, in order to service your customers. The customers nowadays often have internet and can download firmware upgrades and upgrade their products themselves, and it can be done safely, without the fear of the device never working again, if it was turned off during an upgrade.
If you plan on implementing a firmware upgrade feature for your device, I Recommend reading: Bootloader Design for MCU's in Embedded Systems by jacobbeningo. This excellent document gives you insight in how a bootloader works, which can support firmware upgrade and how to implement it in a safe and robust way.