Original Publication Date: 1990-Sep-01
Included in the Prior Art Database: 2005-Mar-16
Christensen, NT: AUTHOR [+1]
Disclosed is a mechanism for simplifying the control of error recovery in an environment containing: Multiple requesters; Multiple stages of processing for each possible request; Multiple requests in progress simultaneously.
a mechanism for simplifying the control of
error recovery in an environment containing:
Multiple stages of processing for each possible
Multiple requests in progress simultaneously.
For an error
occurring at any given stage of processing, it is
necessary to identify the requestor and the type of request, and
issue the appropriate recovery action command to the requestor.
to accomplish this consists of reducing the
Primary Data Flow of the system (shown in Fig. 1) to a duplicate
Recovery Model 1 of Fig. 3. The Recovery Model 1 contains all
registers and data paths of the Primary Data Flow, but each register
and data path width is reduced in size to that required only to
accommodate a requestor Identifier (ID) and an operation identifier
(CMD). IDs and CMDs are gated from stage 2a to stage 2n of Fig. 3
in the Model in synchronism with the transfers from stage 3a to stage
3n in the Primary Data Flow (delayed in time by one cycle) using the
same gating signals.
Thus, when an
error is detected in the primary data flow, the
error indication is passed to the Recovery Model, where immediate
determination of requestor and operation is made and the recovery
action initiated. Only a single error signal is required from each
processing stage to the Recovery Model, and a single recovery command
bus is required from the Rec...