PPT Slide
CRA-1 I/O Devices
- Memory-mapped I/O vs Explicit I/O instructions
- Program writes I/O instructions to specific memory locations and reads other specific memory addresses to receive information from I/O devices
- CRA-1 has one disk controller with one hard disk drive
- Disk drive has 4,096-byte blocks (aka sectors)
- Two I/O commands for disk controller: read block and write disk block
- Note OS-style C++ code using memory-mapped I/O in Figure 2.2; Chapter 14 has an excellent quick overview of “real world” I/O devices