JPH02147983A - Apparatus for managing time of lan storage terminal - Google Patents

Abstract

PURPOSE:To set time error of a built-in timer within a specified value by providing a time information sending means for sending time information every specified time and a plurality of terminals having a controller for receiving the sent time information and modifying and controlling it. CONSTITUTION:Many terminals 2a, 2b,...2n of work stations or the like are housed in Ethernet 1 being a kind of Local Area Networks (LAN) and a time information sending device 10 for sending time information at one time with packets for Ethernet with constant time intervals is further housed. After each terminal 2 is subjected to specified signal conversion, it is input to a processor 5. A built-in timer 3 or the like for generating time information to be reference for file management etc. of files created in the terminal 2 is connected to the processor 5. This enables the built-in timer 3 to carry out correct management since the timer is set within a constant range of errors and free from nonconsistency.

Description

[Detailed Description of the Invention] "Industrial Application Field" The present invention relates to a time management device for LAN-accommodated terminals, which manages the time of a built-in timer of each terminal accommodated in a local area network such as Ethernet. LAN
The present invention relates to a time management device for an accommodating terminal.

``Conventional technology'' In large-scale research institutes and universities, LAN (Local Area Network) such as Ethernet
Increasingly, systems are being adopted in which multiple terminal devices such as workstations are connected to a computer (ks) and the databases, files, etc. created by each device are shared.

In such a distributed environment where terminal devices are deployed on a network, "time" is sometimes used as a basis for managing attributes such as the time when an operator operated each terminal device and the date and time of file creation. . This "time" is managed by a hardware timer built into each terminal device.

"Problem to be Solved by the Invention" By the way, there are variations in the operation of conventional hardware timers. For example, if the time advances by one second per day, if this is left unchecked, the time between terminal devices will change. This causes inconsistencies in the files and causes problems in file management, etc. In other words, for example, hundreds of terminal devices may be accommodated on the Ethernet, and the management of files created on each terminal device requires not only the "year, month, and day" of the creation, but also the "hour, minute, and second." Management is performed by classifying up to

However, as mentioned above, if the time becomes incorrect on a "second by second" basis, file creation times may overlap or be reversed, making it impossible to perform accurate file management.

The present invention has been made focusing on such circumstances,
The object of the present invention is to provide a time management device for a LAN-accommodated terminal that can keep the time errors of built-in timers of a plurality of terminal devices accommodated on a LAN such as Ethernet within a predetermined value.

``Means for Solving the Problems'' The present invention includes a time information sending child actor that sends time information on a local area network at predetermined intervals, and a time information sending child actor that is accommodated on the network and receives the sent time information. , a time management device of a LAN-accommodating terminal with a plurality of terminal devices having a control unit that controls to correct the time indicated by the clock when the error between the clock and the indicated time exceeds a predetermined value. It is equipped with.

In this way, the time information is sent out all at once from the standard time information sending child actor at predetermined time intervals, and all terminal devices receive this time information, compare it with the time of their own built-in timers, and set a predetermined value. If it exceeds the limit, we will take control to correct it. Therefore, it is possible to always keep the built-in timers of terminal devices accommodated in the same network within an extremely narrow error range.

"Example" Hereinafter, the present invention will be explained based on illustrated embodiments.

FIG. 1 is a block diagram showing one embodiment of the present invention.

The Ethernet 1, which is a type of LAN, includes many terminal devices 2a such as workstations.

2b...2n, and further transmits time information all at once in Ethernet packets (broadcast packets) at fixed time intervals.
is accommodated. What is a broadcast packet?
As a header of a packet sent out on Ethernet,
A packet with a meaningful header that should be received by all accommodating terminals at the same time.

A processor 11 that manages the entire time information sending device 10 includes a reference time generation circuit 12 that generates a reference time and a timer 13 that generates an interrupt at set time intervals.
A memory 14 is connected to the memory 14 for temporarily storing packets with headers for simultaneous transmission on the Ethernet. The ROM 16 includes a time information sending device 10.
The overall control program is stored, and when the set time comes, a broadcast signal is sent via the transceiver 15, which is an interface to the Ethernet 1.
Packets are sent out en masse to Ethernet 1.

The detailed configuration of the terminal device 2 described above is shown in FIG. 2. That is, broadcast packets and other packets arriving from the Ethernet 1 are received by the transceiver 4, subjected to predetermined signal conversion, and then input to the processor 5. The processor 5 includes a terminal device 2
A built-in timer 3 is connected to generate time information (hours, minutes, and seconds) that serves as a reference for file management of files created in , and a disk 6 for temporally storing data and displaying time, etc. Peripheral device 7 for data input
is connected, and further connected is a ROM 8 that stores a program for controlling the entire terminal device 2.

Next, the operation of the time management device of the LAN accommodating terminal configured as described above will be explained.

First, in the time information sending device IO, the timer 13 issues an interrupt to the processor 11 at a preset interrupt address at a preset time interval.

The processor 11 that has accepted the interrupt signal reads the current time data from the reference time generation circuit 12 and sends it out as a broadcast packet to the Ethernet 1 via the transceiver 15.

On the other hand, this broadcast packet is simultaneously received by all the terminal devices 2a, 2b, . . . , 2n.

Next, the operation of the terminal device that receives the broadcast packet will be explained along the flowchart shown in FIG.

Broadcast packets and other packets arrive via transceiver 4. Among these received packets, the processor 5 first determines whether or not they are broadcast packets (step ①).
). This is because the types of broadcast packets include not only time information, but also, for example, emergency notification matters, so it is necessary to distinguish between these.

Step 2): Determine whether or not a time update header indicating time information is added to the received broadcast packet. If there is no header for time update, step
This becomes a packet processing routine (step ■).

If the received broadcast packet has a time update header (step ■; Y), the processor 5
Under the control of , the data at that point is read from the built-in timer 3 and transferred to the disk (step 2). Next, it is determined under the control of the processor 5 whether the error between this data and the received time information is within a preset error (step 2).

If the error exceeds the setting error, step ■:
N), the processor 5 corrects the time of the built-in timer 3 so that it falls within the setting error (step ■). After making the corrections, we go back to the routine of waiting for broadcast packets. Furthermore, if it is within the error range, there is no need to take any action, and the process waits for a determination as to whether or not a broadcast packet has been received again (step 2; Y).

In this way, the time data of the built-in timers of all terminal devices will always fall within the predetermined setting error range.

In this embodiment, a case is shown in which the time information sending device 10 is connected to the Ethernet 1 as an independent device.

However, as shown in FIG. 4, the time information transmitter 10A, which has the same function as the time information transmitter 10, is
It may be set within 0. In this case, for example, the memory 14 shown in FIG. 1 can be used as the memory of the main body of the terminal device, and the ROM 16 can be replaced with an auxiliary storage device such as a disk. Furthermore, timer 1 generates interrupts to the processor periodically at fixed intervals.
If the terminal device main body has 30 functions, it may be used instead. In this way, the cost of the entire device can be kept low, and the device can be configured to be compact.

"Effects of the Invention" According to the present invention, the built-in timers of all terminal devices accommodated in a LAN are secured within a certain range of error and no inconsistency occurs, so file management can be performed in units of seconds, for example. Even if it is done, it is possible to carry out accurate management.

[Brief explanation of the drawing]

The figures show a time management device for a LAN accommodating terminal according to an embodiment of the present invention, in which Fig. 1 is a block diagram showing the overall configuration, Fig. 2 is a block diagram of the terminal device, and Fig. 3 is a terminal device. A flowchart showing the operation of the apparatus, and FIG. 4 is a block diagram of the overall configuration showing a modification of the present invention. 1...Ethernet (local area network), 2...Terminal device, 3...
・Built-in timer, 4.15...Transceiver, 5.11...Processor, 12...Reference time generation circuit. Applicant Fuji Xerox Co., Ltd. Agent Patent Attorney Umeo Yamauchi Figure 2 Figure 3

Claims (1)

[Scope of Claims] Time information transmitting means for transmitting time information on a local area network at predetermined intervals; A LAN accommodating terminal comprising: a plurality of terminal devices each having a control unit that controls to correct the time indicated by the clock when the error between the time indicated by the clock and the time indicated by the clock exceeds a predetermined value. Time management device.