Server controller configured to snoop and receive a duplicative copy of display data presented to a video controller

• US 6,233,634 B1
• Filed: 08/17/1996
• Issued: 05/15/2001
• Est. Priority Date: 08/17/1996
• Status: Expired due to Term

• Current Assignee: Hewlett Packard Enterprise Development LP (Hewlett-Packard Enterprise Company)
• Original Assignee: Compaq Computer Corporation (HP Inc.)
• Inventors: Myers, George H., Gagliardi, Louis R., Tavallaei, Siamak, Clark, Gordon R.
• Primary Examiner(s): DHARIA, RUPAL
• Application Number:
  US08/697,678
• Time in Patent Office: 1,732 Days
• Field of Search: 395/182.04, 395/183.07, 395/509, 395/182.09, 395/182.1, 395/182.05, 395/182.13, 395/306, 395/200.09, 345/507, 345/509, 345/522, 361/86, 307/66, 307/86, 307/130, 365/229, 709/217, 714/6, 714/31, 714/11, 714/12, 714/7, 714/15, 710/126
• US Class Current: 710/313
• CPC Class Codes: G06F 11/0709 in a distributed system consisting of a plurality of standalone computer nodes, e.g. clusters, client-server systems
• CPC Class Codes: G06F 11/0748 in a remote unit communicating with a single-box computer node experiencing an error/fault remote testing G06F11/2294
• CPC Class Codes: G06F 11/2294 by remote test

Abstract

A communication system is presented whereby sequences of video screens sent from a host CPU to a video controller can be stored and subsequently retrieved by a terminal located remote from the host CPU. The host CPU and video controller form part of a server arranged within a distributed computing system. An administrator situated at the remote terminal can retrieve select video screens produced during server operations to determine information regarding the server configuration and possible causes of server failure or future failure. The sequence of video screens thereby represent video screen changes stored upon a server controller adapted for coupling to the server expansion bus. The video screen changes represent a sequence of video screen changes occurring prior to server failure or after server reset. Those changes provide beneficial information to an administrator located remote from the server, and allows the administrator to communicate with the server using several possible communication protocols. The server controller snoops display data written from the host CPU to the video controller and mirrors the display data upon buffers within the server controller. Information within the buffers can be called upon by a remotely situated administrator regardless of whether server power is lost in the interim.

Claims

1. A computer, comprising an expansion bus upon which a video controller and a server controller are locally connected, wherein said server controller monitors said expansion bus to detect write operations of display data destined solely for a volatile media of a display device associated with said video controller, and wherein said server controller comprises a controller memory for receiving said display data associated with a detected write operation simultaneously sent to said video controller.

2. The computer as recited in claim 1, wherein said server controller monitors said expansion bus without asserting mastership thereof.

3. The computer as recited in claim 1, wherein said server controller comprises detection logic for decoding said write operations within a video address range.

5. The computer as recited in claim 1, wherein monitoring of said expansion bus comprises snooping.

6. The computer as recited in claim 1, wherein said server controller is a slave unit.

7. The computer as recited in claim 1, further comprising:

a bus bridge coupled between said expansion bus and a PCI bus; and

a second video controller coupled to said PCI bus whereupon said second video controller is deactivated during times when said controller memory and said video controller are receiving said display data.

4. A computer comprising an expansion bus upon which a video controller and a server controller are locally connected and a server controller memory;

wherein said server controller is configured to monitor said expansion bus to detect write operations of display data destined solely for a volatile media of a display device associated with said video controller; and

wherein said server controller comprises detection logic configured to decode said write operations within a video address range and a data transceiver for communicating said display data associated with a detected write operation from the expansion bus to the controller memory simultaneously with transfer of said display data to said video controller.

8. A server controller, comprising:

a controller bus interposed between a controller memory and a processor; and

detection logic locally coupled between an expansion bus associated with a server and said controller bus said detection logic configured to detect a write cycle of display data on said expansion bus destined solely for volatile media of a display device, and for forwarding display data within said write cycle to said controller memory prior to completion of said write cycle.

9. The server controller as recited in claim 8, wherein said write cycle comprises an address cycle followed by a display data cycle.

10. The server controller as recited in claim 8, wherein said processor is coupled to grant mastership of said controller bus to said detection logic.

11. A server controller comprising:

a controller bus interposed between a controller memory and a processor; and

detection logic locally coupled between an expansion bus associated with a server and said controller bus, said detection logic configured to detect a write cycle of display data on said expansion bus destined solely for volatile media of a display device and for forwarding display data within said write cycle to said controller memory prior to completion of said write cycle;

wherein said processor is coupled to grant mastership of said controller bus to said detection logic to cause said detection logic to assert a signal on said expansion bus to forestall termination of said data cycle until after mastership of the controller bus is granted to the detection logic.

12. The server controller as recited in claim 11, wherein said detection logic comprises a defeat timer for counting a predefined number of expansion bus clock cycles after termination of said data cycle and, at the termination of said predefined number of expansion bus cycles, said detection logic relinquishes mastership of said controller bus.

13. A method for snooping a write cycle of display data forwarded across an expansion bus from a server to a video controller, comprising:

detecting on said expansion bus said write cycle of display data occurring within a video address range using detection logic coupled to said expansion bus and by a controller bus to a controller memory;

obtaining mastership of said controller bus by said detection logic;

forwarding said display data occurring within said detected write cycle to said controller memory at substantially the same time in which said display data is also forwarded across said expansion bus to said video controller; and

relinquishing mastership of said controller bus by said detection logic upon termination of said write cycle.

14. A method for snooping a write cycle of display data forwarded across an expansion bus from a server to a video controller said write cycle including an address-cycle followed by a data transfer cycle, said method comprising:

detecting on said expansion bus said write cycle of display data occurring within a video address range using detection logic;

obtaining mastership of a controller bus by detection logic operably coupled to a controller memory;

forwarding said display data occurring within said detected write cycle to said controller memory at substantially the same time in which said display data is also forwarded across said expansion bus to said video controller; and

and wherein said detection logic relinquishes mastership of said controller bus prior to termination of said address cycle.

15. A method for snooping a write cycle of display data forwarded across an expansion bus from a server to a video controller, comprising:

detecting on said expansion bus said write cycle of display data occurring within a video address range using detection logic;

obtaining mastership of a controller bus by detection logic operably coupled to a controller memory;

forwarding said display data occurring within said detected write cycle to said controller memory at substantially the same time in which said display data is also forwarded across said expansion bus to said video controller; and

obtaining mastership of said controller bus upon termination of said write cycle by a processor operably coupled to said controller memory thereby relinquishing mastership of said controller bus by said detection logic.

16. The method as recited in claim 15, wherein said processor is coupled to a communication unit in communication with a terminal located remote from said server, and wherein said processor retrieves and forwards input data from said communication unit to said controller memory during times when said mastership of said controller bus is relinquished by said detection logic.

17. The method as recited in claim 15, wherein said communication unit comprises a modem coupled in communication with a terminal located remote from said server, and wherein said communication unit forwards output data to said terminal during times when said mastership of the controller bus is relinquished by said detection logic.

18. A computer system comprising:

a processor coupled to a first bus;

a system memory coupled to the processor;

an expansion bus;

at least one bus bridge coupled between the first bus and the expansion bus;

a video controller coupled to the expansion bus;

a video memory coupled to receive video data from the expansion bus;

a server controller coupled to the expansion bus, the server controller configured to monitor the expansion bus to detect write operations of video data to the video memory and to receive a copy of the video data associated with a detected write cycle substantially simultaneously with the receipt by the video controller of said video data over said expansion bus.

19. The system of claim 18 and further comprising a display device coupled to the video controller.