system
Given the following post, respond as if you're commenting on Reddit:
human
What exactly is happening when a computer or other digital device "freezes," and what is taking place once it finally catches up?

I work at a distribution center, so I essentially spend my entire shift using an RF scanner. The devices freeze up quite often, and once they unfreeze, they cycle through all the inputs you made during its downtime. What all is taking place while it's having its little digital crisis?
gpt
It's a classic producer/consumer problem.  There are two pieces of code, one producing data to be processed, the other consuming data.  When the producer isn't working, the consumer has nothing to do.  When the consumer isn't working, the queue gets backed up.

So, let's think of that little device.  It's running some kind of multi-tasking operating system (it's able to do stuff while other stuff is waiting, and switch between those tasks on the fly).  It's got some memory, so it's able to hang onto information in a buffer.

Alright, there's a process that runs the laser scanner.  When it recognizes an input, it puts the scan into the buffer, queuing it up for some other process to process it.  Another process takes scans from the buffer and reaches out to the server wirelessly asking info about the scan.  When it gets the info it needs, it tosses that info up on the screen for you to work with.

Now, let's say the server is having a bad day (lots of people using it, admin spilled coffee on it, etc.)  It's taking longer than usual to process the request.

The process handling the scanner is still working, even if the process handling the scans is hung up.  Each scan puts a new input into the buffer, waiting to be processed.

The server finally gets back on track, and the process puts the info on screen, but notices that there are more scans in the queue, so it sends those off to the server as well, one at a time.  The server is all caught up now, so they get processed pretty quick.