I/O Flashcards
What’s an input?
A hardware component used to enter data and instructions into a computer
What’s an output?
A hardware component used to receive information from a computer
What’s a bus?
It’s a public place, type of network architecture where every node is involved in communication with equal access to a set of wires
What does a node need to do to send a message?
Address, what type, announce the data, ensure that nodes don’t collide
Advantage and disadvantage of bus architecture?
Easy to add new devices and possible bottleneck
What are the two types of non-bus network?
Point-to-point connection and mesh network
Does point-to-point connection need an address?
No
What does mesh network do?
It settles a connection between nodes and it routes messages using addresses
How do you calculate a bandwidth?
Lane speed by a number of lanes
What’s an address line?
Designates source or destination of data on the data bus
What’s a control line?
To control access to and use of data and address lines
What’s a data line?
Provide a path for moving data between systems
What does CPU-bus interface do?
Registers staging data to go in and out of CPU
What’s MAR?
Memory Address Register it holds the address of reads or writes to go on the address line
What’s MBR?
Memory Buffer Register, it holds data to go on or retrieve from data lines
What’s a system in the bus hierarchy?
Connects CPU to the main memory on the system board
What’s an expansion bus?
Allows the CPU to speak with I/O devices
What does writing to I/O address do?
Transmits commands e.g. sends data to the device
What does reading I/O address do?
Read from the device
Explain what data buffering do
Transfer rate into and out of main memory or CPU gets high
What does rate in data buffering do?
Orders lower magnitude of devices and covers a wider range
What happens to data buffering and I/O?
Sends rapid bursts from main memory and using data rates it buffers the data to be sent to I/O devices
What does error detection do?
It reports errors back to the CPU
What’s a difference between I/O Devices and Device Drivers?
I/O are hardware connected to the bus and Device Drivers are a software taking responsibility for all communication
What’s are typical I/O steps?
- CPU asks I/O module to check status of device
- Returns device status
- If ready, CPU requests data
- I/O obtains a unit of data from device
- Data is transferred from I/O to CPU
What are different I/O operations out there?
Polling, Interrupt-Driven and DMA (Direct Memory Access)
What’s memory mapping?
Assigns dedicated RAM to represent devices, have them read from RAM themselves and no logic is needed
What’s does CPU IO pin do?
That tells and gives logic for IO, frees up address space
Northbridge-Southbridge Architecture which one is faster?
Northbridge
What does IRQ do?
Interrupts the request
What’s a current trend for I/O with bus speed-ups (Northbridge and Southbridge)
Southbridge -> Northbridge -> CPU silicon
