Sleep Mode on Computer Processor Bus to Aid in Field Replaceable Unit Isolation
Original Publication Date: 1987-Jun-01
Included in the Prior Art Database: 2005-Feb-01
A technique is described whereby computer processors, used in conjunction with input/output (I/O) attachments, are provided with the ability to aid in the isolation of defective I/O circuit cards attached to the processor bus. The concept described herein provides a distinct addressing bit pattern, called a sleep mode, so that diagnostic operations can aid in the analysis and determination of faulty I/O circuit cards attached to a common bus. The concept is particularly useful in performing remote diagnostics, whereby the servicing may take place via telephone lines or radio frequency (RF) links, thereby isolating a faulty circuit card. Since many circuit cards, such as I/O attachment drivers, may be attached to a microprocessor bus, as shown in Fig. 1, any one or more of the circuit cards could develop a defect.