xv6 reading homework

Throughout this semester, we expect that you will read the entire implementation of the xv6 kernel, accompanied by the xv6 book, which explains the rationale and design underlying the kernel's implementation. (The source code is also available as a Lions-style PDF)

For this lecture, read the following files in the xv6 kernel implementation:

• kernel/console.c
• kernel/uart.c
• kernel/kernelvec.S

Look for the line

    tx_busy = 0;

in uartintr() in kernel/uart.c. Delete that line. Run the kernel with make qemu. What happens? Why?

You may find Chapter 6 of the book useful in understanding interrupts and device drivers.

Submit your answer in an ASCII text file named homework.txt to the corresponding "Lecture N" assignment on Gradescope.

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