History FIFO with bypass wherein an order through queue is maintained irrespective of retrieval of data

A method of maintaining a data queue, including the steps of:

• maintaining a write pointer indicating write locations in the data queue at which data items are to be written;
• maintaining a read pointer indicating read locations in the data queue from which data items are to be read;
• upon each write event to the data queue, incrementing the write pointer, to maintain a history of data events in the data queue in order of arrival;
• and
• maintaining a multistage bypass mechanism configured to provide access to items that have been written to the data queue in advance of a latency time of the data queue, wherein an order in which items progress through the data queue is maintained irrespective of an order in which said bypass mechanism accesses said items.

An I/O system including a circular FIFO queue and a bypass circuit, the I/O system configured to operate under control of control logic, the control logic including:

• a write pointer module configured to maintain a write pointer to indicate write locations to which data is to be written in the queue in order of arrival;
• a read pointer module configured to maintain a read pointer to indicate read locations to which data is to be read from the queue;
• and
• a data access module configured to retrieve data that has been written to the queue from the bypass circuit in an order different from that in which the data was written to the queue, wherein an order in which data progresses through the queue is maintained irrespective of an order in which said data access module retrieves said data;
• wherein the write pointer module is configured to increment the write pointer upon each write data event to the queue.