@AC 01:30
I am afraid it is less sane than that.
There are physical sectors - specific areas of silicon on a chip, and there are logical sectors that the operating system asks to read and overwrite. There is also a map that converts logical sector numbers into physical sector numbers. The map is stored in physical sectors, and maintained by the flash controller chip. The operating system does not have access to the map.
When you ask the operating system to delete a file, the operating system writes a few sectors. One will be the directory containing the file. Another will be the sector containing the file's inode (file size, creation/modification/access dates, where the file is stored on the disk). There may also be some changes to sectors to account for some newly deallocated space.
The flash controller writes the data for each of these logical sector writes to some pre-erased physical sectors, then updates the map so that requests requests to read these logical sectors return data from the newly mapped physical sector. At some point the physical sectors that contain the old contents of the directory, inode, free space list, journal and so on get erased. The flash controller has to keep track of which sectors are erased, how many times they have been erased, and where the map is. Writing a single logical sector to flash can result in several physical sectors being written or erased.
During all of this, you may have noticed that none of the data for the file that was deleted has been modified at all. The flash controller will dutifully preserve the file's contents until the operating system decides to allocate those logical sectors to a new file.
A good way to massively improve the performace of flash disks would be to add a new disk command that allowed the operating system to tell the flash controller which sectors no longer contain useful information. This would give the flash controller advanced warning of which sectors can be erased, so it has a wider choice of erased sectors to choose from for the next write operation.
An even better solution would be to forget about complex flash controllers completely and let the operating system maintain the logical to physical map itself. (Linux already has a choice of controllerless flash specific file systems available, but linux users get to pay for expensive performance hitting hardware that works around lack of development in a certain operating system).