JP2003015781A - Client computer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To surely perform remote maintenance such as BIOS rewriting even when an external power source being a main power supply source is turned off, that is, power failure is generated, or even when a small capacity of incorporated battery whose maintenance is not necessary is installed. SOLUTION: The client computer for remotely performing maintenance processing such as the update of function through a network is provided with a means for allowing a CPU 1 to perform maintenance processing based on a remote control signal received from the network, a main power source 5 for supplying an operation power source necessary for performance of the maintenance processing by using an external power source, an auxiliary power source system for backing up the operation power source by an incorporated batter 6 at the time of performing the maintenance processing, and a means for operating the CPU 1 at the time of performing the maintenance reprocessing at an extremely lower speed clock than a normal operation.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a client computer capable of remotely performing maintenance such as function update via a network.

[0002]

2. Description of the Related Art A client computer connected to a server via a network is an application (application program) from the server as required.
The software and hardware equipment can be reduced in weight by receiving the provision of. Such a system model is called a thin client,
This model attracts attention as reducing both the load on the server side and the maintenance load on the client side.
It is used in OS systems.

A client computer can receive maintenance of function updates by automatically downloading and installing an application from a server, but a BIOS (Basic Input / Output System) program that manages not only the application but also the basic function of the system. If you also download and rewrite automatically,
Remote maintainability can be further enhanced (for example, Japanese Patent Laid-Open No. 10-187454).

[0004]

The above-mentioned conventional client computer can automatically update internal programs such as applications and BIOS by remote maintenance performed via a network. However, the updating operation is normally performed. The operation is the same as when it is used, that is, at the normal operating speed. In order to be able to receive the above-mentioned remote maintenance at all times, the computer is kept in a constantly operating state.
However, it is not preferable in terms of power saving to keep the computer running regardless of whether it is used or not.

As a means for saving power, there is remote power control that automatically turns on the power via the network only during maintenance, but the client side uses a commercial AC power source (AC100V), which is the main power source, that is, an external power source. Not usable when turned off. For client computers built into business equipment such as POS terminals, maintenance is limited to the closed hours such as night so that there is no hindrance to business use. This time zone is for power saving and safety management of facilities. For many reasons, the external power supplies (AC power supplies) of the computer system are often turned off all at once.

In order to enable remote maintenance even when the external power supply is off, there is a system in which a power backup system using a built-in battery is configured and the power is turned on by remote control only during maintenance. However, there is a limit to supplying the normal operating power of a computer configured to operate with an external power source with only the built-in battery.
Even if only the program update processing such as the above is performed, in order to back up the operating power supply with the built-in battery, a considerably large capacity built-in battery is required.

[0007] In particular, the BIO that controls the basic functions of the system
Unlike that of the application, the rewriting of S must be completed once without being interrupted once it is started. Therefore, the built-in battery that backs up the power supply for the rewriting operation needs to have a sufficiently large capacity margin. However, such a large-capacity built-in battery significantly increases the equipment load on the client computer. In addition, the use of large capacity batteries requires maintenance.

The present invention has been made in view of the above problems, and an object thereof is to provide a BIOS with a small-capacity built-in battery that requires less maintenance even when a power failure occurs when an external power source is turned off. A client computer capable of reliably performing remote maintenance such as rewriting is provided.

[0009]

Means for Solving the Problems According to the means of the present invention, in a client computer capable of remotely performing maintenance processing such as function update via a network, the maintenance processing is performed based on a remote control signal received from the network. A main power source for supplying an operating power source required for executing the maintenance process using an external power source, and an auxiliary power source system for backing up the operating power source with an internal battery when executing the maintenance process, A means for operating the CPU at the time of executing the maintenance processing with a clock significantly slower than in the normal operation is provided.

According to the above means, remote maintenance such as BIOS rewriting can be surely performed by the built-in battery having a small capacity which requires less maintenance even during a power outage in which the external power supply is turned off. The above means can also be applied to remote maintenance of internal programs other than BIOS, such as firmware and applications.

In the above means, when the CPU is activated by a remote power-on operation performed via the network, the activation can be performed by a low-speed clock, so that the built-in battery at the start of the maintenance process. Can be surely prevented from being consumed. As a concrete means for doing this, a means for switching the operating clock frequency of the CPU between a high speed and a low speed is provided, and the CPU is always activated by the low speed clock when the control signal for instructing the power-on is received from the network. It suffices to form a simple initial setting state.

Further, a battery capacity check circuit for detecting whether or not the built-in battery has a sufficient remaining capacity for backing up the operating power supply for the maintenance process is provided. Based on the detection by the battery capacity check circuit, the battery capacity check circuit is provided. By providing the control means for determining whether to execute the maintenance process, it is possible to reliably prevent the execution of the maintenance process from being interrupted by a power failure of the external power source. The battery capacity check circuit can be configured using a voltage comparison comparator that checks the remaining capacity of the battery based on the voltage of the battery.

The above maintenance process can be performed using data provided via the network. For example,
The program provided via the network is the CP
The maintenance process can be performed with low power consumption by causing U to execute the low-speed clock.

The maintenance process for updating the BIOS can be performed using the data provided through the network. In addition, BI using the data provided via the network
While performing the OS update maintenance process, CP
By acquiring the program to be executed by U via the network, the maintenance processing described above can be performed by remote control without increasing the equipment load of the client computer. Furthermore, the maintenance process for firmware and application updates can be performed using the data provided via the network.

In the above-mentioned means, if the data received from the network is temporarily stored in the RAM and the maintenance process for updating the internal software is performed using the data stored in the RAM, the communication time by the network is calculated. It can be the shortest time required for reception.
As a result, remote maintenance of a large number of client computers connected to the network can be performed in a short time.

Packet data can be used for remote maintenance by the network. While receiving the packet data addressed to its own address from the network, it detects whether the received packet data contains the data to instruct the maintenance mode, and if it contains the data, it outputs the power-on signal. By activating the CPU at a low speed clock, remote maintenance by packet data can be performed even while the built-in battery is backed up.

When the packet data addressed to its own address received from the network includes a power-on command command, it is determined whether or not the packet data includes maintenance data for instructing the maintenance process. . When the maintenance data is included, the CPU clock setting is maintained at a low speed, and when the maintenance data is not included, the CPU clock is switched to the high speed for normal operation. The determination process as to whether or not the maintenance data is included can be performed by the CPU activated by the low speed clock.

Normally, the CPU often does not support switching the clock frequency during operation. Therefore, when the clock of the CPU is switched from low speed to high speed, it is necessary to issue a reset to the CPU to initialize it. However, it is not preferable to use a signal that initializes the entire system, such as a normal power-on reset, because circuits other than the CPU (for example, LAN controller) will also be reset. Therefore, a CPU-only reset that is effective only when the clock is switched is provided. This reset is a software reset issued by the CPU. If the clock is switched by the clock switching circuit when this reset is issued, the CPU is reset at the same time, so there is no risk of the CPU malfunctioning. Note that this is not the case with a CPU whose clock frequency can be arbitrarily changed during operation.

A unitized LAN controller can be used as a means for connecting to the network. This LAN controller can be provided with a function of detecting a control signal for instructing power-on. LAN
The controller may be provided with a function of receiving packet data addressed to itself and issuing a power-on signal for activating the CPU when there is a frame having its own MAC address in the received packet data. it can.

It is desirable that the built-in battery is a rechargeable secondary battery and that it is always charged by the main power source. The type of the built-in battery is not particularly limited, but a lithium ion battery is desirable, for example.

[0021]

1 is a block diagram of a client computer according to an embodiment of the present invention. The client computer shown in the figure is a kind of thin client model computer used by being incorporated in a device such as a POS terminal, and has a CPU (main computer).
1, LAN controller 2, PMU (power management unit) 3, clock generator 4, clock switching circuit 41, main power source 5 using commercial AC power source as external power source, built-in battery 6 as auxiliary power source, battery capacity It has a check circuit 7 and the like, and is used by connecting to a network.

The LAN controller 2 selectively receives the packet communication data distributed from the network to its own address (MAC address). The PMU 3 responds to a remote control signal received via the network to control the power supply of each unit. The clock generator 4 switches and outputs a high-speed clock (for example, 100 MHz) and an ultra-low-speed clock (for example, 32 kHz) as an operation clock of the CPU. The clock switching circuit 41 controls the clock switching under the control of the CPU 1 and also generates a reset signal for restarting the CPU 1 when the clock is switched. The built-in battery 6 is a secondary battery having a relatively small capacity, and is floatingly charged by the main power supply 5.

The LAN controller 2 and the PMU 3 are backed up by a built-in battery 6 so that a minimum operating power supply can be secured even when the main power supply 5 is off.
In addition to the LAN controller 2 and the PMU 3, the built-in battery 6 enables the CPU 1 to supply the minimum operation power required for executing processing such as BIOS rewriting with an ultra-low-speed clock in a form of backing up the main power supply 5. It is provided.

The LAN controller 2 is unitized so that it can be plugged in to an expansion bus of a computer with a connector, for example. The unit 2 is supplied with operating power so that it is always backed up by the built-in battery 6 in order to wait for reception from the network. Therefore, for example, the administrator of the client computer may use an external power source (commercial AC power source) for facility management or other reasons
When the power is cut off, only the power source supplied from the built-in battery 6 operates. Therefore, the LAN controller 2 needs to be configured so that the power consumption during standby is as small as possible, but this can be performed relatively easily by limiting its function to the control described later.

FIG. 2 shows an operation flowchart in the main part of the client computer described above. In FIG. 1 and FIG. 2, when the LAN controller 2 receives a control signal addressed to its own address from the network, it receives a PMU.
3 responds, and the power is supplied only to the minimum necessary portion for the CPU 1 to perform the BIOS rewriting process (S1, S
2). As a result, the clock generator 4 is activated in the ultra-low-speed clock generation mode. The CPU is activated in the operation mode of the ultra-low speed clock to execute a predetermined control program (S3: maintenance execution mode).

In this case, the LAN controller 2 constantly monitors whether or not the control signal addressed to its own address is received from the network, and when the control signal addressed to its own address is received, the control signal is supplied to the power source of the computer. It is determined whether or not the signal is an instruction to turn on. Then, when the signal instructing the power-on is received, the power-on signal is issued to the PMU 3. That is, when a wake-up signal for remotely starting the computer is received through the network, a control signal (power-on signal) for cold starting the computer is issued. C based on this wake-up signal
The operating power of the PU1 is supplied, and thereby the CPU1 is activated (cold start). This activation is performed by the low speed clock (for example, 32 kHz) as described above. After booting, the CPU 1 first executes a program stored in a predetermined boot area, and shifts from this program to the execution of the next control program.

The control program executed here is different from the application executed in the normal operation, and is different from the BIOS.
It is created so that it can operate without depending on OS or OS. In the processing by this control program, first, a received signal (packet data) from the network is analyzed and it is determined whether the received signal is a maintenance signal for instructing rewriting of the BIOS (S4). If the received signal is not the maintenance signal but the signal instructing the activation of the normal operation, the clock frequency is reset to the normal high speed mode (for example, 100 MHz) and the CPU is restarted (S41).

When the received signal is the maintenance signal, it is determined whether the main power source 5 is usable (S5). If the main power source 5 cannot be used because the external power source is turned off, the capacity of the built-in battery 6 is checked (S6). If the main power source 5 cannot be used and the capacity 6 of the built-in battery is insufficient, it is determined that the operation is impossible due to insufficient power source, an error is returned to the network, and the operation returns to the first standby mode (S61,
S62).

In this case, in the operation of this embodiment, although an error is returned to the network, the host side sets the waiting time for communication response, and if there is no response within this waiting time, the computer on the terminal side If it is determined that there is an error in step 1, it is possible to return to the first regular mode without returning the above error.

When the main power source 5 is usable or the capacity of the built-in battery 6 is sufficient, a reply indicating that the BIOS update process is possible is sent to the network, and then the BIOS data sent from the network is read. Then, it is temporarily stored in an appropriate memory (RAM) (S7). When the reception and the temporary storage of the BIOS data are normally completed, the BIOS data temporarily stored in the memory is written in a predetermined BIOS area (S8: BIOS rewrite). When BIOS rewriting is completed, CPU with ultra-low speed clock
The control program No. 1 is terminated and the process returns to the first standby mode (S9).

FIG. 3 shows an example of the format of packet data received from the network. As shown in the figure,
Received data is data such as IP header and IP address,
It is composed of option data, CRC and the like. By carrying the data indicating the above-mentioned maintenance mode, the BIOS data, and the like on the received data and transmitting the data over the network, it is possible to perform remote maintenance by designating an arbitrary terminal.

As described above, the client computer of the present invention is a client computer capable of remotely performing maintenance processing such as function update via a network, and the maintenance processing is performed based on a remote control signal received from the network. A main power source for supplying an operating power source required for executing the maintenance process using an external power source, and an auxiliary power source system for backing up the operating power source with an internal battery when executing the maintenance process, It is provided with means for operating the CPU at the time of executing the above maintenance processing with a clock that is significantly slower than that during normal operation. This client computer operates the CPU at the time of executing the maintenance processing with a clock at a speed significantly lower than that at the time of normal operation, so that the maintenance processing can be executed with power consumption much lower than that at the time of normal operation. You can

Generally, the power consumption of a computer increases as the operating clock frequency of the computer increases. In order to increase the processing capacity of the computer, it is necessary to operate it with a clock having a sufficiently high frequency. In normal operation,
In order to secure the required processing speed, the clock is operated with a clock having a frequency as high as possible (for example, 100 MHz or higher). In this case, a large operating power is consumed according to the high clock frequency. In order to supply the necessary electric power from the battery in this normal operation, a very large capacity battery is required even if only the above maintenance is performed. Such a large-capacity built-in battery significantly increases the burden on the client computer. In addition, the use of large capacity batteries requires maintenance.

In the above-described client computer of the present invention, the CPU for executing the maintenance process is clocked at a speed (for example, 32 kH) which is much slower than in the normal operation.
By operating in z), the maintenance process can be performed with much lower power consumption than in the normal operation. As described above, the power consumed by the system including the CPU and the peripherals that operate in synchronization with this CPU is approximately proportional to the operating clock frequency. For example, a system that operates with a 100 MHz clock during normal operation
When operating with a clock of kHz, the power consumption can be reduced to 0.032 MHz / 100 MHz = 1/3125 in calculation. Actually, it is not as calculated, but at least low power consumption can be expected. As a result, even during a power failure when the external power supply is turned off, remote maintenance such as BIOS rewriting can be reliably performed with a small-capacity built-in battery that requires less maintenance.

FIG. 4 shows the configuration of the present invention as a PMU (power
3 is a block diagram showing the management unit: power supply control circuit) 3. FIG. In the figure, the battery capacity check circuit 7 is composed of a voltage detection comparator 71. The voltage detection comparator 71 compares the voltage of the backup internal battery 6 with a predetermined threshold value to detect whether or not the internal battery 6 has a predetermined battery capacity or more. The detection result is sent to the PMU 3 as information (battery voltage status) indicating the remaining state of the battery capacity.

LAN controller (LAN control circuit) 2
Analyzes the packet data received from the host on the server side via the network and identifies the information type included in the packet data. When the LAN controller 2 receives the packet data including the maintenance signal for instructing the BIOS rewriting or the like, it sends a power-on signal to the PMU 3.

The LAN controller 2 forming the network connection means has an external power source (AC1) which is a supply source of the main power source 5.
00V) is turned off, the built-in battery 6 is provided so that the minimum operation power supply required for receiving the packet data and analyzing the frame content thereof is supplied even during a power failure.
Power is backed up by. The backup built-in battery 6 is, for example, a small secondary battery such as a lithium-ion battery, and is constantly charged (floating charge) by the external power source during a non-power failure in which the external power source (AC100V) is supplied. ing. Therefore, although not shown, the main power source 5 shown in FIG.
A floating charging circuit for constantly charging the battery 6 is built in regardless of whether the main power supply of the system is on or off.

The PMU 2 performs the next operation based on the power-on signal issued from the LAN controller 2, the remaining battery capacity information (battery voltage status) given from the battery capacity check circuit 7, and the on / off state of the external power supply. 1) to 3), that is, (1) CPU, RO
It controls the supply of backup power to M, RAM and the like. (2) The clock switching circuit 41 controls high-speed / low-speed switching of the clock frequency generated by the clock generator 4. (3) A system reset signal for restarting the CPU 1 is output.

FIG. 5 shows a communication sequence when the client computer according to the present invention receives a BIOS rewriting command from the server-side host via the network. In the figure, the state of charge of the built-in battery 6 is BI.
The sequence when the OS is rewritten is shown.

In the figure, first, the host is the BIOS.
Packet data including a power-on command command (Wake Up frame) is transmitted to the client computer to be rewritten (S1). This packet contains a network address (MAC address) that identifies the client computer.

The client computer receiving this packet data checks the state of charge of the built-in battery 6 (S2). In this check, if it is determined (OK) that there is a battery remaining capacity necessary for BIOS rewriting, CP
After starting U with a low-speed clock, an IP address assignment request is transmitted to the host (S3). As described above, the remaining capacity of the built-in battery 6 is determined based on the voltage check of the battery 6 by the voltage detection comparator 71. The CPU is activated from the power-off state, but this activation is performed with the above-described low-speed clock (for example, 32 kHz). After this activation, the host is requested to be given an IP address. By giving an IP address from the host in response to this request, data communication with the host is started (S4).

The client computer, to which the IP address is assigned, requests the host for the execution program and the BIOS data for rewriting the BIOS (S5). In response, the host sends the BIOS rewriting program and the BIOS data (S6).
The client computer executes the BIOS rewriting process by the program and data sent from the host (S7). This rewriting process is performed by the low speed clock described above. When the processing ends, the client computer turns off the power to stop the operation (S
8).

FIG. 6 shows that the client computer according to the present invention rewrites the BIOS when the host on the server side receives a command for rewriting the BIOS through the network because the state of charge of the built-in battery 6 is insufficient. Shows a communication sequence when is not performed. In the case of the figure, the host sends packet data including a power-on command command (Wake Up frame) to the client computer which is going to rewrite the BIOS (S1).

The client computer receiving the packet data checks the state of charge of the built-in battery 6, and it is determined that the battery level is insufficient by this check (N
If G), the CPU is not started (S2). Therefore, in this case, the response to the packet data, that is, the request for assigning the IP address to the host is not made. The host determines that the BOOT of the client computer has failed if a response is not returned within a fixed time after sending the packet data (S3).

FIG. 7 is a flowchart showing a more specific operation example of the client computer described above. In the figure, first, when packet data is input from the network to the LAN controller (LAN control circuit) 2, the LAN controller 2 determines whether the MAC address of the input packet data and its own MAC address match. judge. The LAN controller 2 is always backed up by a built-in battery. When the above two addresses match, the LAN controller 2 outputs a power-on signal for starting (cold start) the client computer (S1).

When the power-on signal is output, the PMU
(Power management unit) 3 operates, C
Operation power is supplied to the PU 1, a BIOS memory (BIOS-ROM) including a flash memory, a RAM, a clock generator 4, and the like (S2). By the supply of the operating power, the clock generator is started in the low speed mode for the time being, and the clock signal (for example, 32 kHz) having a frequency significantly lower than that in the normal operation mode is generated (S3).
The CPU 1 is activated by being supplied with power, and this activation is performed in the low speed mode by the low speed clock. In this way, the client computer is first activated in the low speed mode based on the low speed clock, that is, in the low power consumption mode. As a result, the client computer can be activated and operated by the backup power source supplied from the built-in battery 6 even if the external power source is off.

The CPU 1 started in the low speed mode reads the packet data received thereafter, and determines whether the present start is the maintenance mode or the normal operation mode (S4, S
5). If the result of the determination is the normal operation mode, a reset for switching the clock is issued, the clock is switched from the low speed to the high speed for the normal operation, and the CP
U1 is reset and restarted (S51). If the result of the determination is the maintenance mode, the operation is continued with the low-speed clock, and it is determined whether or not the external power supply (AC power supply) is on (S6).

In the above process (S51), the clock of the clock switching circuit is switched by the reset issued by the CPU 1 and is restarted from the initial state at the same time, so that the clock can be switched without causing the CPU to malfunction.

When the external power source is off and the maintenance mode is set, the remaining capacity of the built-in battery 6 is checked (S7). If this check determines that the remaining capacity is insufficient, it does not respond to the host (server), turns off the power to the main parts of the computer such as the CPU, BIOS memory, RAM, and receives packet data. The process returns to the standby state where only analysis is performed (S71).

When it is determined that the external power supply is turned on or the remaining capacity of the battery 6 is sufficient, a response is sent to the host to update the BIOS such as the update device name and update program data.
Receives data necessary for updating etc. from the network. The received data is temporarily stored in RAM (S8).

When the data reception and the storage of the received data in the RAM are completed, maintenance processing such as BIOS update is executed based on the data stored in the RAM (S9). This maintenance process is performed in the low speed mode described above.

FIG. 8 shows a detailed configuration example of packet data used in the network. As shown in the figure, the packet data includes a MAC address of a transmission destination, a MAC address (Mac Address) of a transmission source, data indicating a data length, a data body, CRC data for error detection, and the like.

Command data for activating (cold start) the client computer from the host for remote maintenance, a so-called wake up frame, is 6-byte FFh (FFh, FFh, FFh, FF).
h, FFh, FFh) followed by 16 consecutively repeated MAC addresses.

The maintenance person on the host side embeds a Wake Up frame having the MAC address of the terminal (client computer) to be maintained in the data body alone or together with other data. Send it down.

The above-mentioned packet is received by the LAN controller 2 of the client computer (terminal) to be maintained. When the LAN controller 2 receives a packet (packet data) addressed to itself and finds the wake-up frame having its own MAC address in the received packet, the PMU
A power-on signal is issued to (power management unit: power control circuit). With the procedure as described above, the maintenance person on the host side can remotely start an arbitrary terminal.

FIG. 9 shows a configuration example of the battery capacity check circuit 7 used in the present invention. The battery check circuit 7 used in the present invention can be detected by using a voltage detection comparator 71 as shown in FIG. This comparator compares the voltage of the backup battery with a reference voltage source having a predetermined threshold value, and the backup internal battery voltage 6
Is greater than or equal to the above detection threshold value, and the result is output in a binary logic format of "1" and "0".

The output of the backup built-in battery 6 is input to the input terminal of the comparator 71 and is constantly supplied to a circuit or device that always operates in a standby mode, such as the LAN controller 2 described above. The operating power source of the voltage detection comparator 71 may be constantly supplied from the built-in battery 6, but
In order to further reduce the power consumption during standby, LAN
The power is turned on by the power-on signal from the controller 2, PM
The power may be turned off by a reset signal from U2. That is, the battery capacity check circuit 7 may be operated only when necessary.

As described above, the built-in battery 6 is composed of a rechargeable secondary battery such as a lithium ion battery, and is constantly charged via the main power supply 5 when the external power supply (AC 100V) is in the ON state. (Floating charging).

FIG. 10 shows a configuration example of the clock switching circuit 41 used in the present invention. The clock switching circuit 41 shown in the figure is composed of a DFF (data latch flip-flop) circuit 42 and a buffer gate 43 with an enable control terminal. The DFF circuit 42 is
Set by the power-on signal from the LAN controller (LAN control circuit) 2 (latch setting), while PM
It is reset (unlatched) by the system reset signal from U2. The latched output state of the DFF circuit 42 is supplied as a clock selection signal to the clock frequency setting input port of the clock generator 4 via the buffer gate 43. The clock generator 4 switches the frequency of the generated clock according to the logic level of the clock selection signal. Specifically, the signal at that input port is
When it is 0 "(L level), a low-speed clock is generated.
When it is 1 "(H level), a high speed clock is generated. The logic level of the clock selection signal is set based on the power-on signal and the reset signal from the PMU 2. This setting state is the same as that of the DFF circuit 42. It is held by the buffer gate 43.

Although the present invention has been described based on its representative embodiment, the present invention can have various modes other than the above embodiment. For example, in the battery capacity check circuit 7, the remaining capacity of the battery is checked based on the voltage of the battery in the embodiment. However, the remaining capacity of the battery is checked by monitoring the discharged amount and the charged amount of the battery. You may Some recent secondary batteries have a built-in circuit that monitors the remaining capacity of the battery, but when using such a battery, the remaining capacity can be checked using the built-in monitoring circuit. .

In the above description of the embodiment, the BIOS is mainly used.
The remote maintenance for rewriting
It can also be applied to remote maintenance that rewrites other programs, such as maintenance services that remotely rewrite firmware and applications.

With regard to a network for connecting between a host for maintenance and a client computer to be maintained, the present invention includes a WAN such as the Internet, a LAN for communication connection in a specific range, a public telephone network or a mobile telephone connection network. A wide variety of networks such as commercial lines can be used. The communication data format between the host and the client computer is the packet format in the above embodiment, but the present invention can be applied to a data format other than the packet.

[0063]

As is apparent from the above description, the present invention is based on a remote control signal received from a network in a client computer capable of remotely performing maintenance processing such as function update via the network. Means for causing the CPU to execute the maintenance process, a main power supply for supplying an operating power supply required for executing the maintenance process using an external power supply, and an auxiliary power supply for backing up the operating power supply with an internal battery when the maintenance process is executed. Since the system and the means for operating the CPU at the time of executing the above maintenance processing with a clock that is significantly slower than the normal operation, maintenance is required even during a power outage when the external power supply is turned off. The remote maintenance such as BIOS rewriting can be surely performed with a small capacity built-in battery.

[Brief description of drawings]

FIG. 1 is a block diagram of a client computer according to the present invention.

FIG. 2 is an operation flowchart of a main part of the client computer shown in FIG.

FIG. 3 is a diagram showing a format example of packet data received from a network.

FIG. 4 is a block diagram showing the configuration of the present invention by focusing on a PMU.

FIG. 5 shows a client computer according to the present invention as a BI.
It is a figure which shows the example of a communication sequence at the time of OS rewriting.

FIG. 6 is a diagram showing an example of a communication sequence in the case where the client computer according to the present invention is not activated due to insufficient remaining capacity of the built-in battery.

FIG. 7 is a flowchart showing a specific operation example in the main part of the client computer according to the present invention.

FIG. 8 is a diagram showing a detailed configuration example of packet data used in a network.

FIG. 9 is a block diagram showing a configuration example of a battery capacity check circuit used in the present invention.

FIG. 10 is a block diagram showing a configuration example of a clock switching circuit used in the present invention.

[Explanation of symbols]

1 CPU (Main Computer) 2 LAN Controller 3 PMU (Power Management Unit) 4 Clock Generator 41 Clock Switching Circuit 42 DFF (Data Latch Flip-Flop) Circuit 43 Buffer Gate with Enable Control Terminal 5 Commercial AC Power Supply Used Main power supply 6 Built-in battery 7 forming auxiliary power supply Battery capacity check circuit 71 Voltage detection comparator

Claims (15)

[Claims] 1. In a client computer capable of remotely performing maintenance processing such as function update via a network, means for causing a CPU to execute the maintenance processing based on a remote control signal received from the network, and the maintenance. A main power supply for supplying the operating power required to execute the processing by using an external power source, an auxiliary power supply system for backing up the operating power with an internal battery when the maintenance processing is executed, and a CPU for executing the maintenance processing. A client computer comprising means for operating with a clock significantly slower than in normal operation. 2. The client according to claim 1, wherein the CPU is activated by a remote power-on operation performed via a network, and the CPU is activated by a low-speed clock. Computer. 3. The invention according to claim 1 or 2, wherein CP
A means for switching the operating clock frequency of U to high speed and low speed is provided, and an initial setting state in which the CPU is always activated by a low speed clock when a control signal for instructing power-on is received from the network is formed. Characterized client computer. 4. The battery capacity check circuit according to any one of claims 1 to 3, further comprising a battery capacity check circuit for detecting whether or not the built-in battery has a sufficient remaining capacity to back up an operating power supply for the maintenance processing. Then, the client computer is provided with a control means for deciding whether or not to execute the maintenance processing based on the detection of the battery capacity check circuit. 5. The client computer according to claim 4, wherein the battery capacity check circuit includes a voltage comparison comparator that checks the remaining capacity of the battery based on the voltage of the battery. 6. The client computer according to any one of claims 1 to 5, wherein the maintenance process is performed using data provided via a network. 7. The client computer according to claim 1, wherein the maintenance processing is performed by causing the CPU to execute a program provided via a network at a low speed clock. 8. A client computer according to any one of claims 1 to 7, characterized in that maintenance processing for firmware update is performed using data provided via a network. 9. The invention according to any one of claims 1 to 8, wherein a firmware update maintenance process is performed using data provided via a network, and a program for causing the CPU to perform this maintenance process is provided. A client computer characterized by being obtained via the network. 10. The BI according to any one of claims 1 to 7, using data provided via a network.
A client computer characterized by performing maintenance processing of OS update. 11. The invention according to claim 1, wherein data provided via a network is used,
A client computer characterized by performing maintenance processing of application update. 12. The invention according to any one of claims 1 to 11, wherein data received from a network is temporarily stored in a RAM, and maintenance processing for updating internal software using the data stored in the RAM is performed. Characterized client computer. 13. The invention according to claim 1, wherein packet data addressed to its own address is received from the network, and it is detected whether or not the received packet data includes data for instructing power-on. A client computer, wherein the CPU is started at a low speed clock when the data is included. 14. The LA according to any one of claims 1 to 13, which is unitized as a means for connecting to the network.
This LAN controller is provided with an N controller, and this LAN controller receives the packet data addressed to itself and issues a power-on signal for activating the CPU when there is a frame having its own MAC address in the received packet data. A client computer, which is configured as follows. 15. The client computer according to claim 1, wherein the built-in battery is a rechargeable secondary battery and is constantly charged by the main power source.