Need help: Multiple Pi’s, one system, separate jobs

[RedPanther]

In case you’re unfamiliar, I’m in process of working on a distributed computer project. I currently have 1-Pi 4B and 2-Pi3B+’s. The 4B is being used as the main system currently while I figure out how to incorporate the other two systems. So here’s the questions I have in mind today:

How do I use the 4B as the main controller for Ethernet and connection to HDD’s(I already have done), then use one 3B+ as a video and sound controller(HDMI and 3.5mm outs) for the back of my case, and use the other 3B+ as spare USB controller for the front of my case?

Let me clarify, I’m looking to transmit all audio and video output information from the 4B to one 3B+, transmit and receive a connection to the USB controller built into another 3B+ from the 4B. This would allow me to disable the onboard video and sound cards on the main controller, while gaining four more USB 2.0 ports.

Note: At some point the 3B+ for HDMI connection will be switched out with a 4B for a 4K video output, and the other will be upgraded as well to a 4B to add two USB 3.0 ports in exchange for the 2.0. Yes, I know this is going to change some things in the coding down the road, but that’s part of the process of learning and getting better

[wildfire]

Let me clarify, I’m looking to transmit all audio and video output information from the 4B to one 3B+, transmit and receive a connection to the USB controller built into another 3B+ from the 4B. This would allow me to disable the onboard video and sound cards on the main controller, while gaining four more USB 2.0 ports.

Erm, wouldn't a single Pi4b with a (powered) USB hub give all what you want at less cost?

[RedPanther]

Let me clarify, I’m looking to transmit all audio and video output information from the 4B to one 3B+, transmit and receive a connection to the USB controller built into another 3B+ from the 4B. This would allow me to disable the onboard video and sound cards on the main controller, while gaining four more USB 2.0 ports.

Erm, wouldn't a single Pi4b with a (powered) USB hub give all what you want at less cost?

Essentially, yes. However, My Pi stack will be in the front of my case, so I might as well use one of them as a device controller

[RedPanther]

Just as well, since I already have the other two systems, why can’t I learn how to write some code and actually use them how I want?

[wildfire]

why can’t I learn how to write some code

Absolutely no reason, in fact a main priority of the RPF is to encourage such ventures.

and actually use them how I want?

What you want, what is possible & what is economically viable are not the same.

[RedPanther]

Ok then I’ll beg to differ. If we can use SSH connections for terminal access, VNC for mouse and keyboard, GPIO for sound, video, usb, power, Ethernet, and essentially anything we want, then why is my one request impossible?

[RedPanther]

If I can establish a connection to the components over Ethernet or via GPIO connections, then writing a code based around that concept becomes completely possible with these devices.

[wildfire]

Ok then I’ll beg to differ.

Differ about what.

why is my one request impossible?

I am still unsure what your request is and I certainly never said it (whatever it is) was impossible.

Anyway, I'll get my coat. Goodbye.

[RedPanther]

Ok then I’ll beg to differ.

Differ about what.

why is my one request impossible?

I am still unsure what your request is and I certainly never said it (whatever it is) was impossible.

Anyway, I'll get my coat. Goodbye.

There will be a small stack of Pi’s in the back of my case, the main controller Pi in the top corner, and a taller stack of Pi’s in the front.

I would like to write separate codes, one allowing me to transmit and receive Video and Sound data from one Pi to another to practically serve as a Video/Sound card in a desktop set up.

I would also like to write another set of code allowing me to transmit and receive data from the USB ports on a Pi in my front stack to the main Pi, essentially serving as a USB extension device.

[epoch1970]

Mhh. Perhaps Spice (XSpice) could help?
Somehow I don't feel this is going to be an easy project.

[RedPanther]

Mhh. Perhaps Spice (XSpice) could help?
Somehow I don't feel this is going to be an easy project.

I’m not anticipating anything easy for this project. This is my first big computer project, and it all stemmed from curiously working with a Pi ZeroW as a Print server. I have big ambitions that I know can come together with the right help.

You have the right concept of thought with “Spice” though! I’m not going to be running VM’s though. I’m going to be running physical systems

[RedPanther]

Here’s how everything will be set up

[RandomRedMage]

OK so as I see it, this kind of seems like the same idea as I've heard from people requesting information on how to "play better games" using a "cluster" It's not really feasible unless the game is specifically coded to work on the cluster distributing tasks between the nodes. In the same way the idea of using multiple Pis as a single computer is not entirely feasible. At least not with the conventional raspian OS. Perhaps with something like the OS Plan 9 this might be more feasible as it is a distributed operating system. You can learn more about it here: https://9p.io/wiki/plan9/plan_9_wiki/ and even see a plan 9 pi cluster here: https://www.rs-online.com/designspark/a ... -9-cluster

Outside of potentially getting something functional via plan 9 the only other thing I can say is your looking at a network cluster of computers where you will be SSHing or VNCing into different machines for different uses. And that just seems clunky, as you would need a remote viewer server/client capable of file transfer between devices, and arguably you wouldn't truely be able to use one devices usb ports as general use usb ports on another. IE no using the usb ports on one pi as your mouse/keyboard ports for another. As well as you wouldn't really be able to use one pi's hardware as a video/sound card for another pi.

Again this is all speaking with the idea of using conventional linux OS. plan 9 is an os of a different style, specifically built to be distributed between multiple machines and make use of multiple machines. You really would be looking at designing a lot of client/server software handling to share resources. And while some communication can happen between pis over the gpio, that would have to be hand coded and tested quite a bit to even get basic functionality like capturing keystrokes from one and using them on another.

[neilgl]

Looking at one part of the project "transmit all audio and video output information from the 4B to one 3B+"
So the 4B gets (say) a video (with sound) file from the hard disc and sends that file to the 3B+ which then plays it over HDMI ?
That sounds fairly straightforward or am I missing something?

[RedPanther]

Looking at one part of the project "transmit all audio and video output information from the 4B to one 3B+"
So the 4B gets (say) a video (with sound) file from the hard disc and sends that file to the 3B+ which then plays it over HDMI ?
That sounds fairly straightforward or am I missing something?

You hit the nail on the head there. I pretty much want to stream out certain resources to separate boards, but act as one unit