Hi Chris, I am not sure if you classify this as an error or not, whenever we run a command that requires multiple read and writes and acquiring DATABUS bus and whilst the next process runs as the I/O is working in the back, the acquiring DATABUS uses the last second of its transition such as the 246usec in the picture shown as a second in its process time, which theoretically shouldn't be happening. As this example should be idle from 247(including)... 566(including) which is exactly 320usecs and then at 567 it should declare it has finished. However the sample solution includes from (246...565) as idle then uses 566 to declare it has finished as shown in the second picture My code shown in the second picture doesn't do that and so it is off by 1 second per syscall that requires the data bus. Is it supposed to take the last second of the transition time as its first time inside the blocked queue reading/writing? Additionally is there any leniency for marking when your time is off by 1 second?