JP3752893B2 - Power monitoring method for peripheral device, power monitoring device, power monitoring system, and information recording medium - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a power monitoring method, a power monitoring device, a power monitoring system, and an information recording medium for monitoring the power state of a peripheral device such as a printer, a display device, and a scanner connected to a host computer. The present invention relates to a power monitoring method, a power monitoring device, a power monitoring system, and an information recording medium for a peripheral device having a function of notifying a host computer of state information due to a state change including a case where the value is equal to or less than a predetermined reference value.
[0002]
[Prior art]
Among information processing apparatuses such as POS / DCR, those equipped with a printer connected to a host computer (hereinafter simply referred to as a host) and performing printing based on a command from the host are widely used. The host grasps printer status information such as power supply voltage, print head position, paper presence / absence, printer cover open / close status, operation status during paper feed, etc., and controls the printer based on these status information for printing. To do.
[0003]
In general, a printer has a power source independent of a host. A user operates a power switch for turning on / off the power source, and the printer starts / stops operation.
[0004]
[Problems to be solved by the invention]
Conventionally, even if the user turns off the power for some reason with respect to the printer once turned on, the host cannot grasp this fact. For this reason, the host sends print data to a printer that cannot receive print data when the power is turned off, and the print data is not printed.
[0005]
Also, if the power is turned on again after being turned off by the user, the printer can receive print data from the host, but the printer is reset by turning the power off and on, and various settings are initialized. It will be converted. For this reason, there is a problem that the print data sent based on the setting before the power is turned off is not output as expected.
[0006]
On the other hand, it is possible to configure the host to periodically monitor the power on / off state of the printer. However, in order to solve the above problem, monitoring must be performed in a short period, and the throughput of the host is reduced. There was a problem of lowering.
[0007]
It is also possible to configure the printer to notify the host of status information indicating that the printer is turned off and turned on. However, since a new function is added to the printer, There is a problem that it cannot be applied to other printers. If the power off / on state can be grasped only by changing the function on the host side without changing the function on the printer side, there is an advantage that the design is easy and it can be widely applied to existing printers.
[0008]
An object of the present invention is to provide a power supply monitoring method, a power supply monitoring apparatus, a power supply monitoring system, and an information recording medium that can solve the above-described conventional problems and can grasp a power on / off state of a peripheral processing apparatus. is there. A method for monitoring the power source of the printer that enables proper printing even when the printer is reset by turning the power off and on while the printer is in use by grasping the power state of the printer on the host side, It is an object to provide a power monitoring device, a power monitoring system, and an information recording medium.
[0009]
Another object of the present invention is to realize the above-described proper printing in an existing data processing system, for example, a printer system, only by changing the function on the host side without changing the peripheral device side, for example, the printer side. There is.
[0010]
[Means for Solving the Problems]
In order to achieve the above object, the power monitoring method for a peripheral device according to the present invention provides a status to the host computer due to a change in the state of the peripheral device including a case where the power supply voltage of the peripheral device is equal to or lower than a predetermined reference value A power monitoring method in a host computer for monitoring a power supply state of a peripheral device having a function of notifying information, wherein (a) a step of receiving state information notified from the peripheral device, and (b) receiving state information And (c) determining that the power supply of the peripheral device is in an off state when there is no response to the request.
[0011]
When the power supply of the peripheral device is turned off by the user, the power supply voltage of the peripheral device decreases over a predetermined time. This predetermined time varies depending on the peripheral device model, for example, the power supply circuit configuration, and can be obtained experimentally. Then, when the peripheral device is in a high load state, for example, during printing, the power supply voltage rapidly decreases, and in a low load state, for example, in the standby mode, the power supply voltage gradually decreases. When the power supply voltage falls below a predetermined reference value, the peripheral device notifies the host side of status information indicating a power supply abnormality or a non-recoverable error. In response, the host computer requests the current status information from the peripheral device. When the status information from the peripheral device is transmitted due to power-off, the peripheral device is in an inoperable state or in a power-off state when the status information is requested from the host computer. Cannot respond to. Therefore, when there is no response, it can be determined that the power is off.
[0012]
In this case, the step (b) may be executed after a lapse of a considerable time from when the power supply voltage of the peripheral device becomes equal to or lower than a predetermined reference value until at least the peripheral device becomes inoperable. .
[0013]
In the present invention, the step (a) includes a step (a1) detecting whether or not all the bit strings of the state information have been received, and only when all the bit strings have been received, the steps (b) and ( When c) is executed and all the bit strings are not received, it may be determined that the peripheral device is powered off. This is because it can be estimated that the peripheral device has not been able to transmit all the bit strings of the status information because the power supply voltage has dropped rapidly.
[0014]
In the present invention, the step (a) includes the step (a2) of determining the contents of the received state information, and the state information includes a case where the power supply voltage of the peripheral device is equal to or lower than a predetermined reference value. Steps (b) and (c) can also be performed only if they are related to non-recoverable errors.
[0015]
The present invention can also be configured to execute the step (a1) prior to the step (a2) and to execute the step (a2) only when all the bit strings are received.
[0016]
In the present invention, the step (a1) includes a step of detecting whether or not there is an error in the notified state information. If there is no error, the step (a2) is executed. Can also be configured to execute step (b) without executing step (a2).
[0017]
Further, the present invention further includes (d) monitoring that the power is turned on, and the step (d) is executed after it is determined that the power supply of the peripheral device is in the off state. You may do it.
[0018]
Here, the step (d) includes (d1) a step of requesting the current state information of the peripheral device, and (d2) a step of determining that the power supply of the peripheral device is in an on state when there is a response to the request. Can have.
[0019]
The present invention can also be configured to execute step (d) before sending data from the host computer to the peripheral device.
[0020]
Moreover, this invention can be comprised so that a process (d) may be performed for every predetermined time interval.
[0021]
The present invention also provides a power supply state of a peripheral device having a function of notifying a host computer of state information due to a change in the state of the peripheral device including a case where the power supply voltage of the peripheral device is lower than a predetermined reference value. The present invention relates to a power supply monitoring device provided in a host computer to be monitored. The power monitoring device of the peripheral device of the present invention includes a receiving means for receiving the status information notified from the peripheral device, a status information requesting means for requesting the current status information of the peripheral device after receiving the status information, And determining means for determining that the peripheral device is powered off when there is no response.
[0022]
In this case, a measuring unit that measures a predetermined time may be provided, and the state information requesting unit may be configured to request the current state information of the peripheral device after a predetermined time has elapsed.
[0023]
The present invention also relates to a system comprising a host computer and a peripheral device connected to the host computer, the system monitoring the power supply state of the peripheral device. In the power supply monitoring system of the present invention, the peripheral device is connected to the host computer side due to the power supply voltage detection means for detecting the power supply voltage and the state change of the peripheral device including the case where the power supply voltage is below a predetermined reference value. The host computer has status information notified from the peripheral device, and has notification means for notifying the status information of the peripheral device and processing means for processing a real-time command from the host computer requesting the status information of the peripheral device in real time. Receiving status information, status information requesting means for transmitting a real-time command for requesting the current status information of the peripheral device after receiving the status information, and if there is no response to the request, the peripheral device is powered off And a judging means for judging that there is.
[0024]
In this case, the host computer may include a measuring unit that measures a predetermined time, and the state information requesting unit may request the current state information of the peripheral device after the predetermined time has elapsed. The power supply monitoring method described above can be supplied as a control program that can be executed by the host-side control unit, and can be provided via a recording medium that records the control program. Alternatively, the control program can be provided via a computer network such as the Internet.
[0025]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an embodiment of the present invention will be described with reference to the drawings. In the following embodiment, in order to facilitate understanding of the present invention, a printer will be described as an example of one of the peripheral devices. However, the present invention is not limited to the printer, and other peripheral devices such as a display device and a scanner. It can also be applied to devices.
[0026]
FIG. 1 is a diagram showing an outline of data communication between a printer and a host of a POS system according to the present invention. In the present POS system, the host 10 and the printer 20 that prints slips, receipts, and the like are connected via an interface so that bidirectional communication is possible. An example of an interface is RS-232C. FIG. 1 shows the main elements of the host and printer. The host 10 includes a status information receiving unit 12, a status information requesting unit 14, a determination unit 16, and a timer 18. The printer 20 includes a power supply voltage detection unit 22, a state information notification unit 24, and a processing unit 26. In addition to the configuration shown in the figure, other components normally included in the conventional host 10 and printer 20 are included. For example, a CPU (Central Processing Unit), a memory, a printing mechanism, and the like.
[0027]
FIG. 7 shows other components of the host. A CPU 104, a RAM (Random Access Memory) 106, a memory such as a ROM (Read Only Memory) 108, a register 110, and an input / output controller 112, and these elements are connected via a bus 114. And the component shown in FIG. 1 is comprised from the combination of the component shown in FIG. 7, and a well-known technique. For example, the timer 18 can be configured by a known technique such as a real-time clock or a counter.
[0028]
The operating system and application software operating on the host 10 and the printer 20 are external storage such as the hard disk drive 116, floppy disk drive 118, and CD (Compact Disc) -ROM drive 120 connected to the memory or the I / O bus 122. The program is provided via the apparatus, and the program is stored in a recording medium such as the hard disk 116A, the floppy disk 118A, and the CD-ROM 120A. Further, it is provided from the remote device 124 via the communication interface 126. The remote device includes a network such as the Internet or a LAN (Local Area Network) and a WAN (Wide Area Network), a peripheral device such as the printer 20, and an interface capable of bidirectional communication.
[0029]
The printer 20 has an automatic status information notification function (ASB: Automatic Status Back, hereinafter referred to as ASB) that automatically notifies the host 10 of various status information on the printer without being based on a request from the host side. . Status information to be subjected to ASB is set in the printer 20 by the host 10 in advance. The printer 20 notifies the host 10 when there is a change in the status information targeted for ASB. By automatically receiving the ASB, the host 10 does not request the printer to notify the status information, and sends a control command and print data based on the information obtained by the ASB. Can be controlled.
[0030]
Status information subject to ASB includes various types of errors such as voltage error error, CPU execution error, print head temperature detection thermistor error, print head home position detection error, printer cover open error, carriage step-out error, etc. Error information can be included. The error information included in the status information is divided into three groups, that is, an error that automatically recovers, an error that can be recovered, and an error that cannot be recovered, depending on a difference in recovery conditions after the error occurs. When any of the errors occurs in the printer, it is expressed by a corresponding bit and notified to that effect.
[0031]
Here, the voltage abnormality error when the power supply voltage of the printer 20 is equal to or lower than a predetermined reference voltage that may hinder its operation is one of the unrecoverable errors. When this occurs, a bit indicating a voltage abnormality error and an unrecoverable error is set and notified to the host 10. In one embodiment, the ASB is composed of a data string of 4 bytes (32 bits), and a bit concerning an unrecoverable error is stored in the second byte.
[0032]
As described above, the host 10 receives the ASB from the printer 20. The host 10 also has a function of sending a real-time command for requesting current status information to the printer 20. Real-time commands are commands that are processed immediately without being stored in the receive buffer. Therefore, the real-time command is processed with priority over normal commands and print data. Then, the printer 20 that has received the real-time command requesting the status information responds to the request for the real-time command by immediately sending the status at the time of reception to the host 10.
[0033]
In the present invention, the host 10 uses a response to the ASB and real-time command from the printer to monitor that the printer 20 is turned off. This is to grasp the on / off state of the power supply without causing a time difference.
[0034]
FIG. 2 is a flowchart of control of the power supply monitoring method according to the first embodiment. In accordance with the procedure shown in the figure, the host 10 detects that the power of the printer has been turned off and notifies the application program running on the host 10 to that effect. In the following, description will be given in order.
[0035]
When the user turns off the power switch of the printer 20 that is being used, the power supply voltage is set to a predetermined reference value before the power supply voltage becomes zero or before the printer 20 becomes completely inoperable. It is detected that the following has decreased. As a result, an ASB having status information of an unrecoverable error is notified to the host 10 (201). In response to this, the host 10 waits for a predetermined time (202), and then transmits a real-time command to the printer 20 to request current status information of the printer (203).
[0036]
FIG. 6 is a diagram illustrating how the power supply voltage drops when the power switch of the printer 20 is turned off. The predetermined time until the real-time command is transmitted is from the time when the power supply voltage of the printer becomes equal to or lower than a predetermined reference value (Vth) until the voltage at which the printer control circuit becomes inoperable (Vop), or when the power supply is turned off. It is necessary to leave a considerable time until it is completely turned off. This considerable time varies depending on the state of the printer at the time when the power switch is turned off. For example, in the case of the printer of this example, when the printer is in a state of high load (601) such as during the printing operation, this equivalent time is as short as about 50 μs, whereas the printer at the time of off is the printer. Is in a low load state such as a standby state (602), it is about 150 ms. Therefore, it is preferable to set a time of 150 ms or more as the equivalent time. These values are obtained experimentally for each printer model. Here, the equivalent time ensures detection of whether or not the printer is turned off, that is, increases the reliability of the detection result. However, if the corresponding time is too long, it may not be possible to detect that the printer is turned off, so it should not be longer than necessary.
[0037]
When the ASB is transmitted from the printer 20 to the host 10 based on the power supply of the printer 20 being turned off, the power supply of the printer 20 cannot operate when the real-time command is transmitted from the host 10. The printer 20 cannot receive the real-time command because the voltage is completely off or completely off. If there is no response from the printer within a predetermined time from when the normal real-time command is transmitted until the response is returned (204), the host 10 determines that the printer is turned off, and The application is notified (205).
[0038]
On the other hand, when the printer 20 transmits an ASB based on another reason (for example, a paper jam error), the printer 20 transmits status information to the host in response to a real-time command from the host 10. Thus, it is determined that the printer 20 is not turned off.
[0039]
FIG. 3 is a flowchart of control of the power supply monitoring method according to the second embodiment. The procedure in this embodiment includes a step of determining the contents of the ASB before sending a real-time command. This is different from the first embodiment. In the following, description will be given in order.
[0040]
When the user turns off the power switch of the printer 20 that is in use, the ASB having the status information of the unrecoverable error is notified to the host 10 as described in the first embodiment (301). The host 10 reads the contents of the ASB from the printer 20 (302). Then, it is determined whether or not the bit of the non-recoverable error in the ASB is set (303), and when the bit is set, that is, when the ASB is based on the non-recoverable error, the above-mentioned first As in the embodiment, a real time command is sent (305) after a predetermined time (304).
[0041]
In step 303, if the ASB is not based on an unrecoverable error, that is, if the error bit is not set, the host 10 determines that the power of the printer 20 is not turned off and receives the next ASB. Wait for. Therefore, in the present embodiment, even if the host 10 receives the ASB, if it is not based on an unrecoverable error, it does not send a real-time command. As a result, unnecessary real-time commands are not transmitted, and the load on both the host and the printer accompanying the transmission and response is reduced.
[0042]
If there is no response from the printer in response to the status information request by the real-time command in step 305 (306), the host 10 assumes that the printer is turned off as in the first embodiment. Judgment is made and this is notified to the application (307).
[0043]
FIG. 4 is a flowchart of control of the power supply monitoring method according to the third embodiment. In the procedure in the present embodiment, in addition to the ASB content determination process in the second embodiment, a process step when the ASB cannot be completely received is included. In the following, description will be given in order.
[0044]
When the user turns off the power switch of the printer 20 that is in use, the ASB having the status information of the unrecoverable error is notified to the host 10 as described in the first and second embodiments (401). ). The host 10 waits for data by setting the port to the reception state for a time until all data of the preset ASB (4 bytes in this example) is received (402). As described above, when the power is turned off, if the printer is in a high load state, the time from when the power switch is turned off until the power is actually turned off may be extremely short. In such a case, before all the bits of ASB are sent, the power supply voltage of the printer falls below the voltage required for data transmission, and data transmission may be interrupted in the middle. Since it is extremely rare that the ASB transmission is interrupted except when the power is turned off, the host 10 determines that this is due to the power off and does not send a real-time command, (409). In this case, it is not necessary to determine the contents of the ASB or send a real-time command for determining power off.
[0045]
In step 402, when all bits are received, a parity check and a frame check are performed to determine whether there is an error in the received data (403). Here, if an error is detected in the received data, the contents of the ASB cannot be read correctly. Therefore, a real time command is transmitted to the printer 20 after a predetermined time (406) without executing steps 404 and 405 ( 407). If there is no response from the printer (408), the host 10 determines that the printer is turned off and notifies the application of this (409).
[0046]
If the received data is normal in step 403, the contents of the ASB are read (404), and it is determined whether or not a bit of an unrecoverable error in the ASB is set (405). Only when the bit is set, a real-time command is transmitted (406, 407), and when there is no response to this, it is determined that the power is off (408, 409).
[0047]
FIG. 5 is a flowchart of control in the host when detecting that the printer is turned on again after the printer is turned off. The present embodiment can be applied to the first to third embodiments.
[0048]
According to the procedure in each of the embodiments, the printer 20 is monitored for power-off (501). Accordingly, when it is determined that the power of the printer 20 is turned off (502), a timer for transmitting a real-time command is set (503). When a preset time-out time elapses (504), the host 10 transmits a real-time command to the printer 20 to check whether the printer 20 is turned on (505). If the printer 20 remains off, the printer 20 cannot respond to the real time command. In this case, the host 10 repeats the transmission of the real time command at predetermined time intervals until there is a response from the printer 20 (503 to 506).
[0049]
When the power of the printer 20 is turned on by the user, the printer 20 can respond to the real-time command. Therefore, if there is a response in step 506, the host 10 turns on the power of the printer 20. (507). Then, the settings before the printer 20 is turned off are transmitted to the printer 20, and the settings of the printer 20 are returned to the state before the power is turned off (508). Each setting stored in the memory of the printer 20 is initialized by the user turning off and on the printer. However, by performing the setting again according to this procedure, it is possible to perform proper printing.
[0050]
As mentioned above, although one embodiment of the present invention has been described with reference to the drawings, the present invention is not limited to the matters shown in the embodiment, and the description of the claims and the detailed description of the invention, as well as the well-known technology. Based on the above, a range in which those skilled in the art can make changes and applications thereof is included.
[0051]
In the above embodiment, the power-on monitoring after the power-off is performed by transmitting a real-time command at a predetermined time interval. However, when data transmission from the host becomes necessary, the real-time command is transmitted prior to this. By transmitting, the power-on state may be monitored.
[0052]
In addition, although it is desirable to use a real-time command for the printer status information request, a normal command stored and processed in the buffer in the order received may be used.
[0053]
In the embodiment, the printer has been described as an example. However, the present invention is not limited to this, and can be applied to a peripheral device such as a display device or a scanner.
[0054]
【The invention's effect】
As described above, according to the present invention, the power state of the printer can be grasped on the host side, and even when the printer is reset by turning the power off and on during use of the printer, an appropriate Printing is possible.
[0055]
In addition, the present invention makes it possible to grasp the power status of the printer by changing the function on the host side without making any changes on the printer side, so it can also be used in existing printer systems with minimal design changes. can do.
[0056]
In the present invention, since the status information is requested from the printer after a predetermined time, the determination of power-off is more reliable.
[0057]
In the present invention, since the status information is not requested in cases other than an unrecoverable error, the load on the host and the printer can be reduced based on the request and the response thereto.
[0058]
Further, in the present invention, when all the bit strings of the status information are not received, it is determined that the printer is turned off without executing the step of requesting the status information. , The load on the host and the printer can be reduced.
[0059]
In the present invention, by using the ASB function and real-time command function of the printer for power supply monitoring, a change in the power supply state can be notified and judged with little time lag.
[Brief description of the drawings]
FIG. 1 is a diagram showing an outline of data communication between a printer and a host according to the present invention.
FIG. 2 is a flowchart of control of a power supply monitoring method according to the first embodiment.
FIG. 3 is a flowchart of control of a power supply monitoring method according to a second embodiment.
FIG. 4 is a control flowchart of a power supply monitoring method according to a third embodiment.
FIG. 5 is a flowchart of control in the host when it is detected that the power is turned on again after it is determined that the power is turned off.
FIG. 6 is a diagram illustrating a state of a power supply voltage drop when a power switch of a printer is turned off.
FIG. 7 is a block diagram showing a main configuration of a host according to the present invention.
[Explanation of symbols]
10 hosts
20 Printer

Claims (25)

In the host computer that monitors the power supply state of the peripheral device having a function of notifying the host computer of state information due to a change in the state of the peripheral device including a case where the power supply voltage of the peripheral device is equal to or lower than a predetermined reference value A power monitoring method,
(A) receiving the status information notified from the peripheral device;
(B) requesting current state information of the peripheral device after receiving the state information;
(C) determining that the peripheral device is powered off when there is no response to the request;
A power supply monitoring method for a peripheral device, comprising: 2. The power monitoring method for a peripheral device according to claim 1, wherein the step (b) includes a period from when the power supply voltage of the peripheral device becomes equal to or lower than a predetermined reference value to at least a voltage at which the peripheral device cannot operate. A method for monitoring a power supply of a peripheral device, which is executed after a lapse of a considerable time. The peripheral device power supply monitoring method according to claim 1 or 2, wherein the step (a) includes:
(A1) It has a step of detecting whether or not all the bit strings of the state information are received, and the steps (b) and (c) are executed only when all the bit strings are received. A power monitoring method for a peripheral device, characterized in that if it is not received, the peripheral device is determined to be in an off state. The peripheral device power supply monitoring method according to claim 1 or 2, wherein the step (a) includes:
(A2) In the case of having a step of judging the contents of the received status information, and the contents of the status information relate to an unrecoverable error including a case where the power supply voltage of the peripheral device is equal to or lower than a predetermined reference value Only, the steps (b) and (c) are executed. 5. The power monitoring method for a peripheral device according to claim 3, wherein said step (a1) is executed prior to said step (a2), and said step (a2) is executed only when all bit strings are received. A power monitoring method for a peripheral device. 6. The power monitoring method for a peripheral device according to claim 5, wherein said step (a1) includes a step of detecting whether or not there is an error in the notified state information, and if there is no error, said step (a2) And when there is an error, the step (b) is executed without executing the step (a2). In the power supply monitoring method of the peripheral device according to claim 1,
(D) The method further includes the step of monitoring that the power is turned on, and the step (d) is executed after it is determined that the power of the peripheral device is in the off state. A method for monitoring the power supply of a device. The peripheral device power supply monitoring method according to claim 7, wherein the step (d) includes:
(D1) requesting current state information of the peripheral device;
(D2) determining that the power supply of the peripheral device is in an on state when there is a response to the request;
A power supply monitoring method for a peripheral device, comprising: 9. The power monitoring method for a peripheral device according to claim 7, wherein the step (d) is executed before data is transmitted from a host computer to the peripheral device. 9. The power monitoring method for a peripheral device according to claim 7, wherein the step (d) is executed at predetermined time intervals. In the host computer that monitors the power supply state of the peripheral device having a function of notifying the host computer of state information due to a change in the state of the peripheral device including a case where the power supply voltage of the peripheral device is equal to or lower than a predetermined reference value A power monitoring device provided;
Receiving means for receiving status information notified from the peripheral device;
State information requesting means for requesting the current state information of the peripheral device after receiving the state information;
Determining means for determining that the peripheral device is powered off when there is no response to the request;
A power supply monitoring device for a peripheral device. In the power supply monitoring device for a peripheral device according to claim 11,
When receiving the state information notified from the peripheral device, the device has a measuring unit for measuring a predetermined time, and the state information requesting unit requests the current state information of the peripheral device after the predetermined time has elapsed. The power supply monitoring apparatus characterized by the above-mentioned. A system comprising a host computer and a peripheral device connected to the host computer, wherein the peripheral device is a power monitoring system that monitors the power state of the peripheral device.
Power supply voltage detecting means for detecting a power supply voltage;
A notification means for notifying the host computer of the status information of the peripheral device due to a change in the status of the peripheral device including a case where the power supply voltage is equal to or lower than a predetermined reference value;
Processing means for processing a real-time command from the host computer that requests status information of the peripheral device in real time, and the host computer
Receiving means for receiving status information notified from the peripheral device;
After receiving the status information, status information requesting means for transmitting a real-time command for requesting the current status information of the peripheral device;
Determining means for determining that the peripheral device is powered off when there is no response to the request;
A power supply monitoring system for monitoring a power supply state of a peripheral device. The power supply monitoring system for monitoring the power supply state of the peripheral device according to claim 13, wherein the host computer has a measuring means for measuring a predetermined time when receiving the state information notified from the peripheral device, The power supply monitoring system for monitoring a power supply state of a peripheral device, wherein the state information requesting unit requests current state information of the peripheral device after the predetermined time has elapsed. 15. The power monitoring system for monitoring the power status of a peripheral device according to claim 13, wherein the peripheral device is a printer. A program for monitoring the power supply state of a peripheral device having a function of notifying the host computer of state information due to a change in the state of the peripheral device including a case where the power supply voltage of the peripheral device is below a predetermined reference value is recorded In an information recording medium,
(A) receiving status information notified from the peripheral device;
(B) after receiving the status information, requesting the current status information of the peripheral device;
(C) determining that the peripheral device is powered off if there is no response to the request;
An information recording medium comprising: 17. The information recording medium according to claim 16, wherein the step (b) includes a lapse of a considerable time from when the power supply voltage of the peripheral device becomes equal to or lower than a predetermined reference value until at least the peripheral device becomes inoperable. An information recording medium to be executed later. The information recording medium according to claim 16 or 17, wherein the step (a) includes:
(A1) a step of detecting whether or not all the bit strings of the state information have been received, and the steps (b) and (c) are executed only when all the bit strings are received, If not received, the information recording medium is characterized in that the peripheral device is determined to be in an off state. The information recording medium according to claim 16 or 17, wherein the step (a) includes:
(A2) a step of determining the content of the received status information, wherein the status information relates to an unrecoverable error including a case where the power supply voltage of the peripheral device is equal to or lower than a predetermined reference value Only the steps (b) and (c) are executed. 20. The information recording medium according to claim 18, wherein the step (a1) is executed prior to the step (a2), and the step (a2) is executed only when all bit strings are received. To record information. 21. The information recording medium according to claim 20, wherein the step (a1) includes a step of detecting whether or not there is an error in the notified state information, and when there is no error, the step (a2) is executed. If there is an error, the step (b) is executed without executing the step (a2). 22. The information recording medium according to claim 16, further comprising a step (d) of monitoring that the power is turned on, wherein the step (d) is determined that the power of the peripheral device is in an off state. An information recording medium which is executed after The information recording medium according to claim 22, wherein the step (d) includes:
(D1) requesting current state information of the peripheral device;
(D2) when there is a response to the request, determining that the peripheral device is powered on;
An information recording medium comprising: 24. The information recording medium according to claim 22, wherein the step (d) is executed before data is transmitted from a host computer to the peripheral device. The information recording medium according to claim 22 or 23, wherein the step (d) is executed at predetermined time intervals.

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