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On Hacking MicroSD Cards (bunniestudios.com)
1 point by peter_d_sherman on Aug 7, 2018 | hide | past | favorite | 1 comment


Selected Excerpts:

"...so it turns out that every flash memory disk ships with a reasonably powerful microcontroller to run a custom set of disk abstraction algorithms."

[..]

"The embedded microcontroller is typically a heavily modified 8051 or ARM CPU. In modern implementations, the microcontroller will approach 100 MHz performance levels, and also have several hardware accelerators on-die. Amazingly, the cost of adding these controllers to the device is probably on the order of $0.15-$0.30, particularly for companies that can fab both the flash memory and the controllers within the same business unit. It’s probably cheaper to add these microcontrollers than to thoroughly test and characterize each flash memory chip, which explains why managed flash devices can be cheaper per bit than raw flash chips, despite the inclusion of a microcontroller."

Translation: Who would have thought that a plain flash memory card -- might have an actual computer on it?




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