Server computer I/O redirection tool

• US 6,170,021 B1
• Filed: 10/19/1998
• Issued: 01/02/2001
• Est. Priority Date: 10/19/1998
• Status: Expired due to Term

• Current Assignee: Hewlett Packard Enterprise Development LP (Hewlett-Packard Enterprise Company)
• Original Assignee: Hewlett-Packard Company (HP Inc.)
• Inventors: Graf, John D.
• Primary Examiner(s): Lefkowitz, Sumati
• Application Number:
  US09/175,802
• Time in Patent Office: 806 Days
• Field of Search: 709/217-219, 710/15-19, 714/46, 714/57
• US Class Current: 710/15
• CPC Class Codes: G06F 2209/544 Remote
• CPC Class Codes: G06F 3/1438 using more than one graphics controller
• CPC Class Codes: G06F 9/4812 by interrupt, e.g. masked
• CPC Class Codes: G06F 9/542 Event management; Broadcasting; Multicasting; Notifications

Abstract

An operating system independent method and apparatus for redirecting a server computer'"'"'s serial device input and display output to a remote console, through the coordinated use of a low-cost dedicated microcontroller integrated within the motherboard of the server computer, and a system management mode facility residing within the CPU microprocessor of the server computer. Upon receipt of a redirection request from a remote console, the microcontroller asserts a system management interrupt request, which is acknowledged and serviced by a handler routine residing within the system management mode. The system management interrupt handler routine then directly accesses serial device input and video output data residing within the server computer, and returns any redirection result to the microcontroller, which in turn, returns the redirection result to the requesting remote console.

Claims

1. A computer system communicating with a remote console via an asynchronous connection, the computer system comprising:

a microcontroller coupled to the asynchronous connection, which receives a redirection request from the remote console, asserts a system management interrupt to process the redirection request, and returns a redirection result to the remote console via the asynchronous connection upon completion of the system management interrupt request; and

a central processing unit (CPU) having a system management mode for controlling a set of routines which are responsive to the system management interrupt asserted by the microcontroller, to process the system management interrupt request, generate the redirection result, and return the redirection result to the microcontroller.

2. The apparatus of claim 1, wherein the system management interrupt request is to read display output data from the computer system.

3. The apparatus of claim 1, wherein the system management interrupt request is to write serial device input data to the computer system.

4. The apparatus of claim 3, wherein said serial device input data is generated from a keyboard at the remote console.

5. The apparatus of claim 3 wherein said serial device input data is generated from a mouse at the remote console.

6. The apparatus of claim 1, wherein the redirection request is processed independent of the operating system residing on the computer.

7. The apparatus of claim 1, wherein the microcontroller is a dedicated application specific integrated circuit (ASIC) device mounted on a motherboard within the computer.

8. The apparatus of claim 1, wherein said redirection result includes video display data related to the computer system'"'"'s boot sequence.

9. The apparatus of claim 1, wherein said redirection result includes text mode screens when an operating system is up and running.

10. The apparatus of claim 1, wherein said redirection result includes text mode crash screens.

11. The apparatus of claim 1, wherein video display modes supported by the redirection include:

80×

25 color (video graphics array (VGA) mode

     3), 80×

25 monochrome (VGA mode

     7) and 80×

50 color.

12. The apparatus of claim 1, wherein the microcontroller optimizes the redirection results returned to the remote console so that only the portions of the display data that have changed from a previous display output operation are sent back to the remote console.

13. The apparatus of claim 1, wherein the CPU is of an Intel ix86 type architecture.

14. The apparatus of claim 13, wherein the CPU is an Intel Pentium processor.

15. The apparatus of claim 1, wherein the system management interrupt is Intel Corporation'"'"'s System Management Interrupt (SMI).

16. The apparatus of claim 1, wherein the system management mode is Intel Corporation'"'"'s System Management Mode (SMM).

17. A method for enabling a computer system to receive serial device data from a remote console via an asynchronous connection, the method comprising the steps of:

transmitting serial device data from the remote console to a microcontroller via the asynchronous connection;

translating the serial device data into a plurality of serial device codes at the microcontroller;

asserting a system management interrupt request at the microcontroller in order to send the serial device codes from the microcontroller to a central processing unit (CPU);

acknowledging the system management interrupt request at the CPU through a system management mode handler residing within the CPU;

sending the plurality of serial device codes from the microcontroller to the CPU upon a successful acknowledgment from the CPU; and

receiving the plurality of serial device codes through the system management mode handler residing within the CPU, the system management mode having a set of routines for directly writing the plurality of serial device codes into a serial device controller.

18. The method of claim 17, wherein said serial device is a keyboard.

19. The method of claim 17, wherein said serial device is a mouse.

20. The method of claim 17, wherein the system management interrupt is Intel Corporation'"'"'s System Management Interrupt (SMI).

21. The method of claim 17 wherein the system management mode is Intel Corporation'"'"'s System Management Mode (SMM).

22. A method for enabling a remote console to retrieve video display data from a computer system via an asynchronous connection, the method comprising the steps of:

transmitting a video display redirection request from the remote console to a microcontroller via the asynchronous connection;

issuing a first system management interrupt request from the microcontroller to retrieve video graphics array (VGA) display register data via a central processing unit (CPU);

acknowledging said first system management interrupt request through a first system management mode handler routine residing within the CPU;

servicing the first system management interrupt request through the first system management mode handler routine residing within the CPU, wherein the first system management mode handler routine retrieves the VGA display register data, and returns the VGA display register data to the microcontroller;

examining the VGA display register data at the microcontroller, then issuing, if appropriate, a second system management interrupt request from the microcontroller to retrieve text screen data from VGA buffer via the CPU;

reading and acknowledging the second system management interrupt request through a second system management mode handler routine residing within the CPU;

processing the second system management interrupt request through the second system management mode handler routine residing within the CPU, wherein the second handler routine retrieves the text screen data from the VGA buffer, and returns the text screen data to the microcontroller; and

receiving the text screen data at the microcontroller from the CPU, optimizing the set of text screen data, then returning the text screen data in an appropriate format to the remote console via the asynchronous connection.

23. The method of claim 22, wherein the first handler routine retrieves a screen mode, a cursor position, and a starting screen address from the VGA CRTC registers.

24. The method of claim 23, wherein if, upon the examination of the VGA CTRC registers at the microcontroller, it is determined that the text screen mode is graphics, an appropriate message is returned to the remote console, and the video display retrieval is terminated.

25. The method of claim 24, wherein the second system management mode handler routine for getting the text screen data accepts the starting screen address and a number of bytes of text screen data desired as arguments.

26. The method of claim 22, wherein the optimization of text screen data in the receiving step includes minimizing the amount of data returned to the remote console by providing only the display data that has changed from a previous video data retrieval.

27. The method of claim 22, wherein the second system management mode handler routine will not return the text screen data if the text screen data has not changed since the previous data retrieval.

28. The method of claim 22, wherein the retrieval of the video display data is performed independent of the operating system residing on the computer system.

29. The method of claim 22, wherein the returned screen data can include:

video display data related to the computer system'"'"'s boot sequence, text mode screens when an operating system is up and running, and a text mode crash screen.

30. The method of claim 22, wherein the returned text screen data includes video display data related to the computer system'"'"'s boot sequence.

31. The method of claim 22, wherein the returned text screen data includes text mode screens when an operating system is up and running.

32. The method of claim 22, wherein the returned text screen data includes text mode crash screens.

33. The method of claim 22, wherein the first and second system management interrupts are Intel Corporation'"'"'s System Management Interrupt (SMI).

34. The method of claim 22 wherein the system management mode is Intel Corporation'"'"'s System Management Mode (SMM).