Electrical computers and digital data processing systems: input/ – Input/output data processing – Peripheral monitoring
Reexamination Certificate
1999-02-11
2001-11-13
Lefkowitz, Sumati (Department: 2181)
Electrical computers and digital data processing systems: input/
Input/output data processing
Peripheral monitoring
C709S219000, C714S046000, C714S057000
Reexamination Certificate
active
06317798
ABSTRACT:
THE FIELD OF THE INVENTION
The present invention relates to remote server management tools in a distributed computing environment, and, more particularly to a method and apparatus to remotely initiate BIOS console redirection on a server computer.
BACKGROUND OF THE INVENTION
Today, distributed computing environments are assuming an increasingly important role in the data processing activities of many organizations. A typical distributed computing environment often includes a plurality of widely dispersed server computers residing in remote locations. These server computers perform data management and other functions for one or more client computers which are attached to each server computer via a computer network. In the past, when a problem occurred with a server computer, an administrator would have to be physically dispatched to the remote server computer location in order to resolve the problem. However, such “boffice visits” were a costly, highly inefficient way of doing business.
As a result, several remote management tools were developed to enable administrators to manage server computers in remote locations via a computer network. Such tools allow administrators and technicians to diagnose and solve problems with remote server computers from a single, centralized server management console.
One type of tool employed in remote server management is PC Basic Input Output System (BIOS) console redirection. The BIOS is responsible for booting the computer by providing a basic set of instructions. It performs all of the tasks that need to be done at start-up time, such as Power-On Self Test (POST), and booting an operating system from a floppy disk drive (FDD) or a hard disk drive (HDD). Furthermore, the BIOS provides an interface to the underlying hardware for the operating system in the form of a library of interrupt handlers. For instance, each time a key is pressed, the Central Processing Unit (CPU) performs an interrupt to read that key. In a similar manner, interrupt handlers also provide an interface to serial and parallel ports, video cards, sound cards, hard disk controllers, and other peripheral devices.
The features of the BIOS permit input/output operations within a remote server to be redirected to a centralized server management console in another location. PC BIOS console redirection tools have been available from Phoenix and other BIOS vendors for several years. These tools provide a method to troubleshoot system boot problems from a remote location using an interface that is like being in front of the system console.
Unfortunately, prior art PC BIOS console redirection tools required someone local to the remote server to enable the console redirection feature using a BIOS setup utility. Often, the remote servers run unattended in physically remote locations, wherein it is often difficult to find a person capable of enabling the console redirection feature. Alternatively, the console redirection feature could be permanently enabled at the remote server. However, permanent enablement of the console redirection feature poses a security threat, since the console redirection feature is not password-protected.
Also, many of the prior art PC BIOS console redirection tools have also required a relatively expensive, dedicated microcontroller to assist in the redirection function. The addition of a dedicated microcontroller to the remote server to perform the console redirection is often prohibitively expensive, especially in low-cost servers.
In view of the above, there is a need for an apparatus and method for remotely initiating BIOS console redirection on a server computer. Furthermore, the apparatus and method for remotely initiating BIOS console redirection preferably does not require a relatively expensive, dedicated microcontroller in order to accomplish its task.
SUMMARY OF THE INVENTION
The present invention provides a computer system communicating with a remote console via an asynchronous connection, where the remote console generates a serial break on the asynchronous connection. The computer system includes a register having a first bit and a second bit, and a break detect circuit coupled to the register for detecting the serial break generated by the remote console and activating a break detect signal in response to the detection. The first bit of the register is set in response to activation of the break detect signal. The break detect signal is de-activated in response to a second bit of the register being set. The computer system also includes a system management interrupt (SMI) circuit for asserting an SMI signal upon detection of the break detect signal. The computer system further includes a memory for storing a basic input output system (BIOS) and an SMI handler routine. Finally, the computer system includes a central processing unit (CPU) coupled to the SMI circuit, the register and the memory. The CPU is responsive to the SMI signal being asserted by the SMI circuit, and identifies the SMI signal assertion as a remote break by reading the first bit of the register. The CPU next processes a subsequent redirection request generated by the remote console by calling the BIOS and the SMI handler routine. Finally, the CPU sets the second bit of the register upon completion of the processing of the redirection request.
In one embodiment of the present invention, the computer system further includes a serial port coupled to the asynchronous connection, such as an RS-232 serial port. The computer system can also include a modem coupled to the serial port. In one embodiment, the computer system includes a software application which is configured to answer an incoming call from the remote console via the modem. Examples of software applications which can answer the incoming call include: Windows NT Remote Access Server (RAS), and PC-Anywhere 32. Alternatively, the modem can be set to an auto-answer mode to handle the incoming call.
In one embodiment of the present invention, the computer system further includes a universal asynchronous receiver-transmitter (UART) coupled to the serial port which manages the serial port and handles communication across the asynchronous connection. In another embodiment of the present invention, the SMI circuit of the present invention comprises a multiplexer, where the output of the multiplexer switches from an IRQ signal to the SMI signal upon detection of the break detect signal.
The computer system includes a CMOS memory chip having an authorization password for controlling remote access to the BIOS of the computer system from the remote console, in one embodiment of the present invention. In this embodiment, a user password entered at the remote console is passed to the computer system. The entered user password is then validated against the authorization password prior to processing the console redirection request.
The present invention also provides a method for enabling remote initiation of basic input output system (BIOS) console redirection on a computer system via an asynchronous connection. The method begins by generating a serial break on the asynchronous connection of the computer system. Next, the computer system detects and processes the serial break, such that the central processing unit (CPU) is placed in system management mode (SMM) upon detection of the serial break. After the CPU is placed in SMM mode, a console redirection request is generated on the asynchronous connection of the computer system. Next the CPU processes the console redirection request such that the SMM of the CPU calls the BIOS and an SMI handler routine to service the console redirection request. Upon completion of processing the console redirection request, the serial break is cleared on the computer system.
In one embodiment of the present invention, the method of processing of the console redirection request at the CPU further includes transmitting a carriage return from the remote console to the CPU, such that the carriage return generates an SMI password initialization request which is processed by an SMI handler routine. Next, a
Hewlett--Packard Company
Lefkowitz Sumati
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