This is an ongoing brain-dump/exploration of communication between/among computers. It’s motivated in part by wanting to setup control systems for household and industrial system. For instance, what if we would like to:

1. Gather moisture data from a moisture sensor?
2. Control the location of a solar panel?
3. Titrate down the concentration of an aquarium nutrient?
4. Link together several single board computers for extra processing power?
5. Send an SMS message when a moisture detector gets wet?

What bus or network connection should we use? What protocol should we use over that connection? What serialization of commands/data/objects should we use?

https://en.wikipedia.org/wiki/Category:Computerbuses

https://en.wikipedia.org/wiki/Telecommunicationsnetwork

https://en.wikipedia.org/wiki/Listofdevicebitrates#Computer_buses List of device bit rates.

Brainstorm: Hierarchies

• Peer-to-peer
• Client-Server

Brainstorm: Connection related terminology

• Bus, moves data between components,
• Network, moves data between components,
• Differences between bus and network.
• power is provided by a bus to the connected component
• e.g. the USB port powers the mouse whereas the Wireless card does not power the Internet
• System bus, connects CPU to RAM (the computer to the memory)
• More Internal
• <---System Bus---
• Front-Side Bus---
• Expansion Bus---
• Peripheral Bus---> More External

Brainstorm: lines (in the sand) of distinction among communication methods

• serial vs parallel
• computer-to-computer vs computer-to-device
• internal vs external
• internal connects all the parts inside a computer, CPU to RAM to Motherboard. Quick, independent
• extenal connects parts outside, printer, mouse, keyboard… (hard drive? internet?)
• system vs front-side vs expansion vs peripheral

Brainstorm: What are the levels of CPU-to-CPU communication?

• Application
• System
• Physical
• Human Understanding
• English
• Binary
• Electronic

Brainstorm: How can we physically communicate from one computer to another?

• USB – connect peripherals, lower performances than SATA, use where SATA isn’t necessary, e.g. in a mouse
• Ethernet.
• WiFi.
• Cable (Coaxial Cable)
• HDMi
• DisplayPort
• Light
• Electricity
• BlueTooth
• Radio
• FireWire
• SATA – connect hard drives to the system bus
• Expansion Cards – connect directly to the system bus
• PCI
• SCSI
• Serial ATA

Brainstorm: Use cases

• CPU to Hard drives, tape, DVD, i.e. persistence, I/O
• CPU to RAM
• CPU to CPU

Brainstorm: What can use to communicate over those physical mediums?

• HTTP
• FTP
• Plain old binary pulses.

Brainstorm: What languages can we use to store more complex stuff?

• HTML/CSS/JavaScript – the representations of the web.
• XML – the representations of hierarchical data.
• JSON – more hierarchical data.
• Binary
• ASCII
• Unicode

Audio/Visual

• DVI
• VGA
• HTMi
• DisplayPort

Emerging Questions

• What differentiates network communication vs bus communication? When should we use each?
• What differentiates internal vs external buses? When should we use each?
• How does a GPOI pin differ from a bus?
• What bus/network choices are optimal (and/or practical) for use cases:
• timing sensitive communication?
• client-server?
• peer-to-peer?
• control systems?
• high throughput?

Some broad, sweeping generalizations that are emerging from my reading, though without citations:

• USB is for connecting peripheral devices to a computer (e.g. mouse, external HDD, keyboard)
• The practical differentiators among internal bus, external bus, and network communication are blurring.
• A pin is a lower level then a bus; a pin is a single on/off that communicates with a CPU; we connect to pins with raw wire.
• A port has a different meaning in hardware than is does in software. For instance, USB is the overarching communication strategy, and it involves both a USB port and a USB cable.

If you expected to find answer, you came to the wrong blog.