hardware-on-demand/docs/02-implementation.md

Hardware on Demand

# Implementation

HoD can exist in a number of separate implementations for hardware, including flashing SD cards, programming eMMC as well as other options for fulfilment and distribution.

## SD Cards

The first (and most simple) implementation of HoD is the ordering, preparation and fulfilment of SD cards.

### Workflow

The following workflow describes the current process of a customer placing an order for SD cards provisioned with their specified OS image.

```mermaid
flowchart TB
    subgraph SD Card Workflow
        direction TB
            subgraph Web Shop
                a1[order placed]--"order(1-5)"-->a2[payment accepted]
            end

            subgraph Warehouse
                a2--"order(1,2,3,5,6)"-->b2{is n in stock?}
                b2 -- no --> b4[order hardware] -->b3[hardware received]--> b2
            end

            subgraph Preload Server
                a2--"order(4)"-->c2
                c2{is balena fleet?}-- yes --> c1{have fleet access?}-- yes --> c3[set OS version and release] --> c4[preload OS image] --> c6
                c1 -- no --> c7[request access] --> c1
                c2-- no --> c5[download file] --> c6
                c6[preloaded image]
            end

            subgraph EtcherPro
                c6 --> d2
                b2 -- yes --> d1[send to operator] ---> d2
                d2[flash] --> d3[validate] --> d4{completed order?}
                d4 -- no --> d2
            end

            subgraph Distribution
                d4 -- yes --> d5[assemble order]
                d5 --"order(5)"--> d6[deliver to customer]

            end
    end
```

An order is composed of the following options:

1. SD Card Type (SanDisk Ultra microSD, etc.)
2. SD Card Size (8GB, 16GB, etc.)
3. Quantity of SD Cards
4. Image file (url to customer's image or balena `org/fleet`)
   - {optional} If it is a balena image, specify OS version and/or pinned application release
5. Delivery address(es)
6. {optional} SD Card branding, e.g. stickers on cases

#### Web Shop

#### Warehouse

#### Preload Server

#### EtcherPro

#### Distribution

## balenaFin

TBD