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File System
zhenwei2972 edited this page Jul 14, 2020
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- Compatible with internal SPI Flash and external SPI Flash
- No 'directories', flat filesystem
- maxchars 32
- blocksize 256
- We shall use custom write-back caching to reduce flash write cycles
- Since the requirement is to note down peers which are in contact for > 30 min
- TempIDs rotate every 15 min, we should note down peers TempIDs seen for >= 5 mins to allow for backend correlation
- Conditions
- /p/[mmdd] is older than 21 days
- Free space is < 20KB
- Process
- Delete /p/[mmdd]* which are >= 21 days, or oldest
/ids
- List of all local Temp IDs
- Looked up to obtain Nth TempID on-demand
/p/[mmdd]
- map of peers TempID to
- a 5-digit running id 0-65535
- org : string
- deviceType
/p/[mmdd]/[id]
- Incident List
- Start Timestamp hhMMss : 3 bytes
- Seen Minutes : 1 byte
- RSSI min, max, mean, var/stddev : 4 bytes
- In locations where certain TempIDs are permanently close to each other
- Define a metric to decide on such devices
- Note down these TempIDs to put them in an ignore / always-together list