01 / Architecture
System architecture
Which macOS sources provide which data, and who publishes it for SwiftUI?
Source → manager → display
MenuBarIO / Code-backed architecture atlas
From a hardware event
to a clear display.
Seven connected diagrams explain MenuBarIO’s components, decision rules, and data paths. Start with the system map, then follow the question you want to understand.
02 / Decision flow
Physical port assignment
Why may a USB device occupy a Mac or dock socket, and when does it remain unassigned?
IOKit signal → decision → port
03 / Sequence
Concurrency and refresh
How do generations prevent slower hardware requests from overwriting newer results?
Request → generation → publication
04 / Decision flow
Source-status meaning
How do zero devices, detection in progress, stale data, and an unavailable source differ?
Result → state → visible data
05 / Data and component map
Groups, paths, and privacy
How do the same models produce three outputs with different information boundaries?
Models → groups → outputs
06 / Component map
Bluetooth battery
How do HID values and bounded BLE reads supplement already connected devices?
HID / BLE → bounded read → battery
07 / Delivery map
Verified delivery
Why are the app and DMG notarized separately, with public bytes checked again?
Archive → notarization → public download
Socket, transport, and hub are different.
USB on a Thunderbolt-capable socket remains USB. A hub group alone does not prove a physical dock port.
Stale is an intentional state.
After a failed refresh, the app keeps the last complete data set and makes its status visible. A successful empty discovery is a real zero result.
Presentation and counting are separate.
A confidently assigned USB device moves from the remaining list to a port, yet still appears exactly once in the external-device count.