Server controller for storing and retrieving sequences of video screens forwarded by a server host computer

• US 6,173,340 B1
• Filed: 10/09/1998
• Issued: 01/09/2001
• Est. Priority Date: 08/16/1996
• Status: Expired due to Term

• Current Assignee: Hewlett Packard Enterprise Development LP (Hewlett-Packard Enterprise Company)
• Original Assignee: Compaq Computer Corporation (HP Inc.)
• Inventors: Clark, Gordon R., Gready, R. Scott, Ellinger, Wesley M.
• Primary Examiner(s): Meky, Moustafa M.
• Application Number:
  US09/169,316
• Time in Patent Office: 823 Days
• Field of Search: 710/1, 710/2, 710/3, 710/6, 710/12, 710/36, 710/37, 710/40, 710/52, 710/56, 710/58
• US Class Current: 710/6
• 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 11/0766 Error or fault reporting or storing
• CPC Class Codes: G06F 11/2294 by remote test
• CPC Class Codes: G06F 11/327 Alarm or error message display
• CPC Class Codes: G06F 11/3414 Workload generation, e.g. scripts, playback
• CPC Class Codes: G06F 11/3466 Performance evaluation by tracing or monitoring
• CPC Class Codes: G06F 11/3476 Data logging G06F11/14, G06F11/2205 take precedence
• CPC Class Codes: G06F 11/3485 for I/O devices
• CPC Class Codes: G06F 2201/88 Monitoring involving counting
• CPC Class Codes: H04L 41/06 Management of faults, events, alarms or notifications
• CPC Class Codes: H04L 41/22 comprising specially adapted graphical user interfaces [GUI]
• CPC Class Codes: H04L 67/01 Protocols
• CPC Class Codes: H04L 67/10 in which an application is distributed across nodes in the network software deployment G06F8/60; multiprogramming arrangements G06F9/46

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 method of storing display data throughout a failure and reset of a computer system, the method comprising:

storing display data forwarded from a host CPU to a video controller during a first time period prior to failure of a computer and during a second time period after reset of the computer such that the display data from the first time period and the display data from the second time period can be accessed after the second time period.

2. The method of claim 1 and further comprising remotely accessing the display data after the second time period.

3. The method of claim 1 and further comprising snooping the address lines of a bus coupled to the video controller and storing data from the data lines of the bus when the address lines carry address signals within a selected address range corresponding to the video controller.

4. The method of claim 1 and further comprising storing the display data within a video memory at substantially the same time as performing the storing step.

5. The method of claim 1 wherein the display data comprise a display screen.

6. The method of claim 1 wherein the display data comprises a change between a current display screen and a previous display screen.

7. A computer system comprising:

a processor;

a system memory coupled to the processor through a processor bus;

an expansion bus;

at least one bus bridge coupled between the processor 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, said server controller including a controller memory for storing display data forwarded from the processor to the video controller during a first time period and during a second time period after the first time period.

8. The system of claim 7 and further comprising a display device coupled to the video controller.

9. The computer of claim 7 wherein the first time period occurs prior to failure of the computer.

10. The computer of claim 9 wherein the second time period occurs after reset of the computer.

11. The computer of claim 7 wherein the second time period occurs after reset of the computer.

12. A computer, comprising:

a host central processing unit (CPU);

an expansion bus operably coupled between said host CPU and a video controller; and

a server controller connected to said expansion bus, wherein said server controller comprises a controller memory for storing display data forwarded from said host CPU to said video controller during a first time period and during a second time period after the first time period.

13. The computer of claim 12 wherein the first time period occurs prior to failure of the computer.

14. The computer of claim 13 wherein the second time period occurs after reset of the computer.

15. The computer of claim 12 wherein the second time period occurs after reset of the computer.

16. The computer as recited in claim 12, wherein said expansion bus comprises an EISA bus.

17. The computer as recited in claim 12, wherein said video controller is coupled to a video memory such that both said video controller and said server controller are responsive to address information within a video address range for simultaneously storing said display data in both said video memory and controller memory, respectively.

18. The computer as recited in claim 12, wherein said host CPU is connected to a local CPU bus.

19. The computer as recited in claim 18, further comprising a bus interface unit coupled between said local CPU bus and said expansion bus.

20. The computer as recited in claim 12, wherein said server controller comprises detection logic coupled between said expansion bus and said controller memory for monitoring said display data forwarded across said expansion bus to said video controller and for thereafter writing said display data to said controller memory.

21. The computer as recited in claim 20, wherein said display data is forwarded across said expansion bus during times when said host CPU writes said display data to said video controller.

22. The computer as recited in claim 12, wherein said controller memory comprises:

a local frame buffer for storing a current display screen of said display data forwarded to said video controller; and

a temporary snapshot buffer coupled to receive the current display screen of said display data forwarded from said local frame buffer;

a snapshot buffer coupled to receive a previous display screen of said display data forwarded from said local frame buffer; and

comparison logic coupled between said temporary snapshot buffer and said snapshot buffer for determining a change between said previous display screen and said current display screen of said display data.

23. The computer of claim 22 wherein said controller memory further comprises a sequence buffer configured to store a change between the current display screen of said display data and a previous display screen of said display data during a time period after which said server receives a first reset.

24. The computer of claim 22 wherein said controller memory further comprises a sequence buffer configured to store a change between the current display screen of said display data and a previous display screen of said display data during a time period before which said server fails.

25. The computer as recited in claim 22, wherein said controller memory further comprises a current reset sequence buffer for storing said change during said second time period.

26. The computer as recited in claim 22, wherein said controller memory further comprises a current sequence buffer operably coupled to a current start buffer, and wherein said change is forwarded to said current sequence buffer and any overflow therefrom is forwarded to said current start buffer during said first time period.

27. A server controller, comprising:

detection logic adapted for coupling to a server to determine the presence of display data forwarded from the server;

a controller memory coupled to said detection logic, wherein said controller memory comprises a local frame buffer and a sequence buffer; and

said local frame buffer is configured to store a current display screen of said display data, and said sequence buffer is configured to store a change between the current display screen of said display data and a previous display screen of said display data.

28. The server controller as recited in claim 27, wherein said change between the current display screen of said display data and the previous display screen of said display data is represented as a packet of digital data.

29. The server controller as recited in claim 28, wherein said packet of digital data comprises fewer binary values than a set of binary values used in storing either the current display screen or the previous display screen.

30. The server controller as recited in claim 28, wherein said packet of digital data comprises a byte of data indicative of a character to be displayed and another byte of data indicative of attributes given to the character to be displayed, said attributes are selected from the group comprising color and intensity.

31. The server controller as recited in claim 27, wherein the change between the current display screen and the previous display screen is represented as a plurality of packets and wherein said packets are arranged in a series representing a sequence of video screen changes which occur after said server receives the first reset.

32. The server controller as recited in claim 27, wherein said current reset sequence buffer is adapted for access by a terminal located remote from said server to display upon said terminal a sequence of video screen changes which occur after said server receives the first reset.

33. The server controller as recited in claim 27, further comprising:

a previous reset sequence buffer configured to store said change between the current display screen of said display data and the previous display screen of said display data upon the server receiving a second reset prior to the first reset; and

said previous reset sequence buffer is adapted for access by a terminal located remote from said server to display upon said terminal a sequence of video screen changes which occur after the server receives said second reset, wherein the current reset sequence buffer is adapted for access by said terminal to display upon said terminal a sequence of video screen changes which occur after said server receives the first reset.

34. The server controller as recited in claim 33, wherein said current reset sequence buffer is adapted for access by a terminal located remote from said server to display upon said terminal a sequence of video screen changes which occur before said server fails.