Virtual Table Purging - FIGnition FUZE Hardware Reference Manual

If it turns out there weren't any dirty blocks in that 'next' sector we just repeat the process
until we purge a sector with dirty blocks. This will be the case in Fig 5.11 when purging
reaches the third from the last Sector (sector 125).
As we go along we carry on adding the new wrapped-around physical block numbers to
the virtual block number list; the current length of the list tells us how many sectors we
have wrapped around [ Fig 5.12]. Here, the next physical page to be used will be page
271.

5.3.3 Virtual Table Purging

There's one last level of complexity! As we add wrapped around virtual block numbers to
the inverse virtual block number list we'll eventually run out of space in the list itself [Fig
5.13]!
FIGnition's solution is to manage the list in two different sectors: when the first sector fills
up, we carry on copying into to the second sector. When there are as many pages used in
the second sector as there are on the Flash disk we'll know that the first sector doesn't
contain any current information and so we can erase it [Fig 5.14].
Fig 5.12
Fig 5.13
Fig 5.14