diff --git a/cs132/index.md b/cs132/index.md index e0427847..12923ded 100755 --- a/cs132/index.md +++ b/cs132/index.md @@ -30,5 +30,5 @@ These notes will likely take the same/similar form to the CS118 notes. The prima 2. [x] [Digital logic](part2.html) 3. [x] [Assembler](part3.html) 4. [ ] Memory systems -5. [ ] I/O mechanisms -6. [ ] Processor architecture +5. [ ] [I/O mechanisms](part5.html) +6. [ ] Processor architecture \ No newline at end of file diff --git a/cs132/part5.md b/cs132/part5.md index 33092bb6..12da6444 100644 --- a/cs132/part5.md +++ b/cs132/part5.md @@ -3,7 +3,9 @@ title: I/O Mechanisms layout: 132/CS132 --- -There is no single IO mechanism that is better than the others – it is important to understand the pros and cons of each mechanism. +
+ There is no single I/O mechanism that is “better” than the others – it is important to understand the pros and cons of each mechanism and the situations where each should be used. +
# Memory mapped I/O @@ -13,7 +15,7 @@ There is no single IO mechanism that is better than the others – it is importa *This means that all addressing modes supported by a CPU are available to I/O.* -> **Advantages.** No need for dedicated instructions, no need for additional hardware. +> **Advantages.** No need for dedicated instructions, or for additional hardware. Addressing modes supported by the CPU are available to I/O. > > **Disadvantages.** We are giving up portions of our memory to I/O devices. This is less of a concern for modern 64-bit processors with more address spaces, but is still relevant when sometimes you have no choice but to use a processor with constrained memory addresses like 16-bit legacy or embedded systems.