readback after write

["hinko.kocevar@cetrtapot.si" <hinko.kocevar@cetrtapot.si>]

Hi,

I have a general question regarding FLASH memories (It does not have to 
do anything directly with linux MTD).
I have connected SPI serial flash to my embedded device. Due to slow 
speed provided by the device I had to drop JFFS2 or similar flash fs in 
favor of accessing the flash memory in raw mode (using stdio I/O 
functions). It works nice and much faster than JFFS2.

What I would like to add to my code is read-back operation after write 
operation, to make sure I haven't overwritten any of the date already 
present on the flash. My intention was to:
- open fp for read and write
- (erase the sector if needed)
- write data to flash
- seek back
- read data back and compare write and read buffer byte-by-byte

This could have major performance downside considering I can transfer 
(R/W) 64K of data in ~700ms to/from the device (SLOWWW). Device is sized 
at 4Mbit. In the worst case this would probably double (triple?) R/W 
times for single operation, which is why I would like to ask if anyone 
has any information/algoritm for such things?

regards,
hinko
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