High-Performance Embedded Computing

4.5 Verification 259

amount of time, so they are handled with interrupts. The file system must also

update the file system tables to remember the state of the file.

A flash read operation is somewhat simpler. Once the file system layer deter-

mines the address to be read, it breaks the read request into a series of data

object reads. The reads are translated into low-level read commands on the

flash. Unlike writes, reads happen at high speed.

Operating systems allow concurrent execution of processes. Concurrent execu-

tion is much harder to design and implement than sequential code. Concurrently

executing processes are also harder to debug. As a result ...