INPUT AND OUTPUT
by Naziha Edries
1. external devices
1.1. three categories
1.1.1. human readable
1.1.1.1. suitable for communicating with computer user
1.1.2. machine readable
1.1.2.1. communicating with equipment
1.1.3. communications
1.1.3.1. suitable with remote devices
2. interface to external
2.1. control signal
2.2. data signal
2.3. status signal
3. keyborad / monitor
3.1. keyboard provide input to the computer
3.2. monitor display data by the computer
4. programmed I/O
4.1. data transfer start by CPU under driver software control to access registers or memory device
5. INTRODUCTION
5.1. the processor and a set of memory modules, the third key element of a computer is a set of I/O modules.
6. major function
6.1. interface to the processor and memory
6.2. interface to one or more peripheral devices
7. I/O Modules
7.1. major function or requirements
7.1.1. control and timing
7.1.1.1. to coordinate the flow of traffic between internal resources and external device
7.1.2. processor communication
7.1.2.1. command decoding
7.1.2.2. data
7.1.2.3. status reporting
7.1.2.4. address recognition
7.1.3. device communication
7.1.3.1. must able to perform device communication
7.1.3.1.1. command
7.1.3.1.2. status information
7.1.3.1.3. data
7.1.4. data buffering
7.1.4.1. an essential task of an I/O module
7.1.5. error detection
7.1.5.1. one class of error including mechanical or electrical by the devices