Interconnection Flashcards
Interconnection structure (Memory)
-N words equal length
-Unique numerical address
-Read/Write data word
-Operation is indicated by read and write control signals
-The location for the operation is specified by an address
Interconnection structure
-Computer as a network of basic modules
-Paths for connecting the modules
-Structure depends on the exchanges
Interconnection structure (I/O)
-Similar to Memory (internal point of view): read/write
-Control more than one external device (port - unique address)
-External data path (input/output)
with an external device
-Interrupt signals (?!)
Interconnection structure (Processor)
-Reading instruction and data
-Write out data after processing
-Use control signals to control the overall operations
-Receive interrupt signals
Interconnection structure (types of transfers)
-Memory to Processor: The processor reads an instruction or a unit of data from memory.
-Processor to Memory: The processor writes a unit of data to memory
-I/O to Processor: The processor reads data from an I/O device via an I/O module.
-Processor to I/O: The processor sends data to the I/O device.
-I/O to or from Memory: I/O module is allowed to ex- change data directly with memory, without going through the processor, using direct memory access.
Other Interconnection structure
-Bus Interconnection
-Point to Point Interconnection
Bus Interconnection
- Communication pathway connecting two or more devices
- Key characteristics: shared transmission medium
-Multiple devices connect to the bus, and a signal transmitted by any one device is available for reception by all other devices attached to the bus
-Signal overlap and become garble —> Only one device at a time can successfully transmit
-A bus consist of multiple communication pathways, lines - each transmit signals representing binary 0 or 1 (e.g. 8-bit unit of data —-> transmit over 8 bus lines)
-System Bus
Bus Structure - Functional Groups
Data lines: to provide a path for moving data among system modules
Address lines: to designate the source or destination of the data on the data bus
Control lines: to control the access to and the use of the data and address lines
Data lines
-Moving data
-Data Bus
-Bus Width - Number of lines
-Data bus width - Key factor in determining overall system performance
Address lines
-Source/destination of the data on data bus - Address Bus
-Bus width - Determines the maximum possible memory capacity
-Address I/O ports
-Higher order bits - select module
-Lower order bits - memory
location or I/O port
Function Groups
-Control the access and the use of the data and address bus.
-Control signals:
–Command signals: Specify operation to be performed
–Timing Signals: Validity of data and address information
-Control lines include: Memory write & read, I/O write & read.
Bus Operation
-If one module wishes to send data to another:
–Obtain the use of the bus
–Transfer the data via the bus
If one module wishes to request data from another module
–Obtain the use of the bus
–Transfer a request to other module over the appropriate control and address lines
Point-to-point Interconnection
-Contemporary systems increasingly rely on Point-to-point interconnect
-Bus system problem
-Lower latency, higher data rate, better scalability
-QuickPath Interconnect (QPI - 2008)
–Multiple Direct Connections
–Layered Protocol Architecture
–Packetized Data Transfer
