GLAST LAT Project
ISOC CDR, 4 August 2004
RFA 12 – EEPROM Write Cycles
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Specific Request
– EEPROMs have a limited number of write cycles before they
become unreliable. It is not clear that the operations
concept/plan factors in this limitation. Understand the number of
writes to EEPROM on LAT from all sources
Response
– The number of EEPROM writes is not an issue using the
TrueFlash File System (TFFS) overlay
• TFFS counts the writes to each sector of the file system
underneath and will move files around to even the wear
across all sectors
• At 100 kByte a day, 5Gbyte would last 50,000 days or
approximately 150 years
– If TFFS is not used, ISOC will work with FSW to develop an
operations plan to manage EEPROM writes
Document: LAT-PR-
ISOC Subsystem
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