In-class notes for 10/28/2020
CS 273 (OS), Fall 2020
HW11 (partial) now available
Project deliverable - part C
Start reading Chapter 6 on deadlock
Deadlock - there is a set of processes, each blocked awaiting an event that can only be caused by another process in that set
I/O (Input/Output)
Layered view of I/O architecture (structural design of I/O support in the OS). E.g.,
User-level code (including user-level libraries)/p>
device-independent OS software
Device driver (in kernel)
interrupt handler
Device controller (hardware)
Device (hardware)
Exercise: goals vs layers
For each of the goals for I/O software, identify layers involved in implementing that goal.
Example: "Both sharable and dedicated devices"
implement in driver - and in parts of the kernel that use the driver.
Other examples will need multiple layers...
Exercise: operations vs layers
For each of the following I/O operations, identify layers that must be involved in implementing that goal.
A line of characters is read from terminal standard input
Up to 100000 bytes are read from a file that is already opened for reading
A memory reference is satisfied in main memory
A USB flash drive is inserted in a USB port
A video is streamed onto the display
A file is copied from one file system to another
An email message is sent
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