JPH03150747A - Digital data recording device - Google Patents

Abstract

PURPOSE:To surely record data by stopping the reception of data when a near- termination signal of a magnetic tape is detected by a near-termination recording protection function consisting of a microcomputer and then restarting the reception of data after confirming the recorded capacity requested by a control instruction. CONSTITUTION:A CPU 5 secures the connection between the terminals A and B of a communication part 1 and receives an instruction to start a near-termination recording protection function. The connection is secured first between the terminals A and C, and the data are inputted to a buffer 2. At the same time, the recording capacity information shown by the instruction is given to a magnetic recording/reproducing part 3. Then a recording operation is started. When the near-termination signal detected based on the reel speed of the transmission side is transmitted to the CPU 5, the connection is secured between the terminals A and D. Then the external reception is interrupted and at the same time the part 3 records the data stored in the buffer 2 and then the remaining insignificant data until the recording equivalent to the designated capacity is through. Then the recording operation is restarted and the normal data are recorded at and after the recorded position of the insignificant data.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a digital data recording device which is an external storage device for a computer and uses a magnetic tape as a recording medium.

BACKGROUND OF THE INVENTION In recent years, digital data recording devices using magnetic tape have come into use for purposes such as backing up hard disks. These devices have a built-in buffer and adopt a transfer control method that returns a normal completion response to the external device indicating completion of writing to the magnetic tape upon completion of the transfer of digital data transferred from the external device to the buffer during recording operation. completed in a short time. Furthermore, protection processing is employed to ensure that digital data in the buffer for which a normal end response has been issued is reliably recorded on the magnetic tape even near the end of the magnetic tape.

As a conventional digital data recording device, for example, a magnetic tape device is disclosed in Japanese Patent Laid-Open No. 1-173219.

A conventional digital data recording device will be explained below.

FIG. 8 is a block diagram showing the configuration of this conventional digital data recording device.

In FIG. 8, 401 is a detection section, 402 is a switching section, 4
Q3 is a buffer, and 404 is a magnetic tape writing section.

The operation of the conventional digital data recording device configured as described above will be described below.

FIG. 9(a) is a diagram showing an example of a magnetic tape used in a conventional digital data recording device, where 0 indicates the logical end which is the end of the recordable area on the magnetic tape, and P
indicates a mark provided at a position before the logical end by the capacity of the buffer 403.

First, in the recording operation, the current tape position is shown in Figure 9 (a).
), the detection unit 401 switches to the switching unit 402.
Since the terminals R and S of are connected, the digital data to be recorded is transferred to the buffer 403 km at high speed, and further transferred to the magnetic tape writing section in synchronization with the recording speed, and recorded on the magnetic tape.

At this time, when the transfer to the buffer 403 is completed, a normal completion response indicating completion of writing to the magnetic tape is issued to the external device.

Further, when the detection unit 401 detects the mark shown by P in FIG. 9(a) during the recording operation, it controls the switching unit 402 to connect the terminals R and T. On the other hand, magnetic tape writing unit 404
When the recording of the digital data stored in the buffer 14o3 onto the magnetic tape is completed, the switching unit 4
The mode shifts to a mode in which digital data transferred via the terminal T of 02 in synchronization with the recording speed is directly recorded onto the magnetic tape. At this time, if writing to the magnetic tape is completed, a normal completion response indicating completion of writing to the magnetic tape is issued to the external device, but before the writing is completed, O When the logical end shown in is detected, an abnormal end response is issued to the external device indicating that writing to the magnetic tape could not be completed.

As described above, in the conventional example, the buffer 4 is
When the mark set previously by the capacity of 03 is detected, the data transfer to the buffer 403 is stopped and the mode shifts to a mode in which data is written directly to the magnetic tape, thereby preventing the buffer 403 from receiving digital data that exceeds the remaining capacity of the magnetic tape. We have implemented a protective process that prevents any damage.

Problems to be Solved by the Invention However, in the conventional configuration described above, when there is an area on the magnetic tape where digital data cannot be recorded correctly, such as a scratch, as shown in U in FIG. The problem is that it may not be possible to complete recording of the digital data for which the completion response has been completed on the magnetic tape.
If the detection unit 401 is unable to accurately detect the mark indicated by P and the logical end indicated by 0 in FIG. 9(a) during the recording operation, digital data will be recorded beyond the logical end. However, this method had the problem of significantly reducing data reliability. For this purpose, a processed magnetic tape with at least marks set at accurate positions is required, which also poses a problem in that it lacks versatility.

The present invention solves the above-mentioned conventional problems, and does not require specially processed magnetic tape such as setting marks, and furthermore, detection accuracy is low when there are scratches on the magnetic tape or near the end of the magnetic tape. It is an object of the present invention to provide a digital data recording device that can complete writing of digital data to a magnetic tape while ensuring high reliability.

Means for Solving the Problems To achieve this object, the digital data recording device of the present invention includes a communication means, a buffer 1 for temporarily storing external data, and a magnetic recording section for recording the external data on a magnetic recording medium. , an end vicinity detection means comprising a speed detection means and a speed comparison means, an end detection means P for detecting the physical end of the front 81 magnetic tape, a remaining amount storage means, and a heavy recording operation on the magnetic tape. It has a configuration including a recording start protection function for starting the recording and a recording protection function near the end.

According to the above-described structure, when the p-end proximity detection means detects near the end of the magnetic tape during recording operation, the end-near record protection function temporarily interrupts data transfer to the ζ buffer. Since the magnetic recording unit executes the recording operation in the V state of the Since it is necessary to judge whether recording is possible according to the state of the data, it is important not to make a mistake in responding to a normal end response. Further, after restarting the transfer, data is recorded again in the area where normal recording has been confirmed, so data reliability is high.

Alternatively, with the above configuration, when the near-end detection means detects near the end of the magnetic tape during the recording operation, the near-end recording protection function temporarily suspends data transfer to buffer 1 and automatically detects the end of the magnetic tape. Since the recording unit measures the remaining recordable amount of the magnetic tape, it is not affected by the detection accuracy of the near-end detection means, and is based on the remaining recordable amount that can be measured according to the actual state on the magnetic tape. You can judge the successful completion response without making any mistakes. Furthermore, after restarting the transfer, data is recorded again in the area where it has been confirmed that normal recording can be performed, so data reliability is high.

In addition, since the end proximity detection means detects that the reel is near the end when the rotational speed of the reel stand on the sending side becomes less than a specified value, it eliminates the need for control processing of the magnetic tape such as mark processing.

EXAMPLE Hereinafter, an example of the present invention will be described with reference to the drawings.

FIG. 1 is a block diagram showing the configuration of a digital data recording apparatus in a first embodiment of the present invention.

In FIG. 1, 1 is a communication unit that transmits and receives digital data and control commands transferred from an external device, 2 is a buffer that temporarily stores digital data, and 3 is a magnetic recording/reproducing unit that records and reproduces digital data on a magnetic tape. Part, 4
5 is a near-end detector which outputs true as a near-end signal when the magnetic tape reaches near the end, and 5 is a microprocessor (hereinafter abbreviated as CPU) equipped with a near-end recording protection function.

), and the near-end detector 4 includes a speed detector 6 that detects the rotational speed of the output reel of the magnetic tape, and a speed detector 6 that outputs true as a near-end signal when the rotational speed becomes less than a preset specified speed. It is composed of a comparator 7.

Digital data recording of this embodiment configured as above! The operation of the device will be explained below. First, the CPU 5 connects terminals A and B of the communication section 1, receives a control command from an external device, and starts the near-end recording protection function if the control command indicates a recording operation on the magnetic tape. .

FIG. 2 is a flowchart showing the procedure of the above-mentioned end-near-record protection function. The CPU 5 performs step 101 in FIG.
controls the communication unit 1, connects the terminal A and the terminal C, starts high-speed transfer of digital data to be recorded from the external device to the buffer 2, and magnetically records the recording capacity information indicated by the control command in step 102. The signal is supplied to the reproducing section 3 to start recording the digital data transferred from the buffer 2 onto the magnetic tape, and then the end vicinity determination loop consisting of step 103, step 104, and step 105 is cycled. On the other hand, during the recording operation, the speed detector 6 detects the rotational speed of the reel stand on the output side of the magnetic tape, and the speed comparator 7 outputs true as a signal near the end when the rotational speed becomes less than a preset specified speed. This notifies the CPU 5 that the magnetic tape is near the end. When the CPU 5 detects that it is near the end in step 105 of the near-end loop, it connects the terminal A of the communication unit 1 to the terminal in step 106, and temporarily interrupts data transfer from the external device to the buffer 12. let The magnetic recording and reproducing section 3 records the digital data stored in the buffer 2 onto the magnetic tape, and subsequently records the meaningless data remaining in the buffer 2 onto the magnetic tape until the recording of the specified capacity is completed. Record.

FIG. 3 is a diagram showing the state of the magnetic tape. Due to uneven tape winding, etc., the position where the near-end detector starts outputting true as the near-end signal is within the range E in FIG. 3(a). Although there is a tolerance as shown in F, a sufficiently large recording capacity is secured for the capacity of the buffer 2 as shown in F up to the physical end position which is the recordable end of the magnetic tape.

Now, the position where the temporary interruption of data transfer from the external device has occurred is indicated by arrow G in FIG. Arrows I indicate the completion positions of recording of the designated capacity of meaningless data. Arrow J in the figure indicates an abnormal area due to scratches or the like on the magnetic tape that was discovered by the magnetic recording/reproducing unit 3 during the recording operation using the read-after-write method.The recording to this area is invalidated, and the correct data is re-recorded in the following area. is recorded.

When the recording operation of the magnetic recording/reproducing section 3 is completed, the CPU 5
In step 107 of FIG. 2, information on the result of the recording operation is received from the magnetic recording/reproducing section 3, and when the information indicates that the recording operation has been completed normally in step 108, the process proceeds to step 109, and the terminal A of the communication section 1 and terminal C are connected to restart the transfer of digital data from the external device to the buffer 2, and in step 110, the magnetic recording/reproducing section 3 is instructed to perform a recording operation from arrow H in FIG. 3 to start recording. Furthermore, when the CPU 5 detects that the data transfer from the external device to the buffer 2 is completed in step 111, it connects terminal A and terminal B of the communication unit 1 in step 112, issues a normal completion response to the external device, and terminates the data transfer. Finish the procedure of the nearby record protection function.

The state of the magnetic tape finally formed by the magnetic recording/reproducing section 3 is shown in FIG. 3(C). The area indicated by arrow J is treated as an invalid area in the same way as in the case of FIG. 3(b), and
Digital data has been correctly recorded in the area from arrow H to arrow I.

On the other hand, if the recording operation cannot be completed normally in step 108, an abnormal termination response is issued in step 113 to indicate to the external device that the recording operation according to the control command could not be completed normally, and the recording protection function near the end is executed. Finish the steps.

Alternatively, if the recording operation is not near the end of the magnetic tape, in step 103 it is detected that the recording operation has ended normally, or in step 104 the external device sends the buffer 2
When the CPU 5 detects that the data transfer to has been completed, it jumps to step 112, outputs a normal end response to the external device indicating that the recording operation according to the control command has ended normally, and ends the procedure of the near-end recording protection function. .

As described above, according to this embodiment, in areas other than the vicinity of the end of the magnetic tape, the signal near the end of the magnetic tape remains true while retaining the function of completing the data transfer with the external device in a short time due to the provision of the buffer 2. If so, the data transfer from the external device to buffer 2 is temporarily interrupted, a recording operation corresponding to the amount of data requested by the control command is executed, and when the recording operation is completed normally, the amount of data equivalent to the requested amount is recorded. By being equipped with a near-end recording protection function, it is possible to secure a recordable area on the magnetic tape, and then resume data transfer and re-record the digital data transferred from the external device in the secured area. Even if the detection accuracy of the near-end detector 4 is low, or even if there are scratches or other areas on the magnetic tape where digital data cannot be recorded correctly,
High data reliability is ensured because a response indicating the result of a recording operation is not erroneously issued to an external device (and data is recorded again in an area where data was actually recorded correctly). It is possible to record to the vicinity of the physical end.

Furthermore, since the near-end detector detects based on the rotational speed of the reel stand on the output side of the magnetic tape, there is no need to set any kind of mark on the magnetic tape in advance, and it is highly versatile.

FIG. 4 is a block diagram showing the configuration of a digital data recording apparatus in a second embodiment and a third embodiment of the present invention.

In FIG. 4, parts that are the same as those in the first embodiment described above are designated by the same reference numerals, and the description thereof will be omitted.

The difference from FIG. 1 is that the CPU 5 is equipped with a recording start protection function, a capacity information confirmation function, and a new end-near-record protection function, and the magnetic tape is recorded at a preset position on the magnetic tape. A capacity information acquisition unit 8 reads capacity information of the magnetic tape, a memory 9 stores capacity information and remaining amount information of the magnetic tape, and detects the physical end of the magnetic tape when the output of the speed detector 6 becomes zero. This is because the termination detector 10 is provided.

The operation of the digital data recording/reproducing apparatus of the second embodiment configured as described above will be explained below. First, when the magnetic tape is mounted, the capacity information acquisition section 8 controls the magnetic recording and reproducing section 3, reads out the capacity information of the magnetic tape recorded in a preset specific area near the starting end of the magnetic tape, and sends it to the CPU 5. Forward. The CPU 5 calculates remaining capacity information, which is the remaining recordable capacity, based on the capacity information, and stores the capacity information and remaining capacity information in the memory 9.

Next, the CPU 5 connects the terminal A and the terminal B of the communication unit 1, receives a control command from the external device, and determines that the control is enabled or that the remaining amount information is valid in steps 201 and 202. Further, when it is determined that the recording capacity requested by the control command is less than the remaining capacity, the procedure of the near-end recording protection function that controls the recording operation on the magnetic tape is started. Further, when it is determined in step 201 and step 202 that the remaining capacity information is valid and that the recording capacity requested by the control command is not full, the remaining capacity information is determined to be unrealizable in step 203. An abnormal end response indicating that the The recording operation on the magnetic tape is started, and step 103. Step 104. Step 105: The terminal neighborhood determination loop consisting of step 204 is cycled. On the other hand, during the recording operation, the speed detector 6 outputs true as the near-end signal when the magnetic tape comes near the end, and the CPU 5 determines whether the magnetic tape is near the end in steps 105 and 204 of the near-end determination loop and the procedure of the capacity information confirmation function. If it is detected that the remaining capacity information is invalid in the vicinity, data transfer from the external device to the buffer 12 is temporarily interrupted in step 106, and in step 205, the magnetic recording/reproducing unit 3 is informed of the physical state of the magnetic tape. Change the instruction to continue recording until the end is detected. The magnetic recording/reproducing section 3 records the digital data stored in the buffer 2 onto the magnetic tape, and subsequently records the meaningless data remaining in the buffer 2 until the end detector 10 detects the physical end of the magnetic tape. recorded on magnetic tape.

FIG. 6 is a diagram showing the state of the magnetic tape, and FIG.
In a), the arrow indicates the logical end position provided to ensure sufficient presumptiveness in the recording state.

The position where the near-end detector 4 starts outputting true as the near-end signal has a tolerance shown in E, but up to the logical end position, which is the end of the area to be used on the magnetic tape, a buffer is used as shown in L. A sufficiently large recording capacity is secured for the capacity of 2. Now, the position where the temporary interruption of data transfer from the external device has occurred is shown by arrow G in FIG. The abnormal areas invalidated by the unit 3 are indicated by arrows J, respectively. The CPU 5 receives information on the results of the operation, and in step 208 calculates a value obtained by subtracting a preset specified capacity from the capacity normally recorded in the area from arrow H to the physical end in FIG. 6(b), That is, the capacity that can be recorded up to the logical end position shown by the arrow K in FIG. 6(b) is calculated as remaining capacity information, and is stored in the memory 9 as valid information. When the CPU 5 determines in step 207 that the unrecorded portion of the recording capacity requested by the control command is greater than or equal to the remaining amount information, the CPU 5 proceeds to step 109, restarts the transfer of digital data from the external device to the buffer 2, and then proceeds to step 110. 6(b) to the magnetic recording/reproducing section 3.
Instruct the recording operation from , and start recording. Furthermore, C.P.
When U5 detects that the data transfer from the external device to buffer 2 is completed in step 111, U5 performs step 11.
At step 2, a normal end response is issued to the external device, and the procedure of the near-terminus recording protection function is ended. The state of the magnetic tape finally formed by the magnetic recording/reproducing section 3 is shown in FIG. 6(C). The area indicated by arrow J is treated as an invalid area in the same manner as in FIG. 6(b), and external digital data has been correctly recorded in the area from arrow H to arrow I.

Conversely, if it is determined in step 207 that the unrecorded portion of the recording capacity requested by the control command is greater than or equal to the remaining capacity information, an abnormal end response is issued in step 113, indicating that the recording operation by the control command cannot be completed normally. This is indicated to the external device, and the procedure for the near-terminus recording protection function ends.

Alternatively, if the recording operation is not near the end of the magnetic tape, in step 103 it is detected that the recording operation has ended normally, or in step 104 the external device sends the buffer 2
When the CPU 5 detects that the data transfer to has been completed, it jumps to step 112, outputs a normal end response to the external device indicating that the recording operation according to the control command has ended normally, and ends the procedure of the near-end recording protection function. .

The procedure for the capacity information confirmation function will be explained below. C
If the PU 5 detects that the near-end signal becomes true in step 105, it proceeds to step 208, and moves from the total recorded area capacity of the magnetic tape, that is, from the beginning of the magnetic tape to the near end shown by arrow G in FIG. 6(b). The total capacity of the area up to the position where the signal becomes true is the maximum capacity from the detection tolerance range of the near-end detector to the logical end position of the magnetic tape, that is, the capacity shown by arrow M in Figure 6(a). If it is less than the value subtracted from the information, it is determined that the actual recordable capacity of the magnetic tape is less than the capacity information and is incorrect information, and in step 209 the capacity information stored in the memory 9 is compared with the remaining capacity information. In this case, the remaining amount of the magnetic tape is determined as described above in the processing from step 204 onwards.

As described above, according to this embodiment, in areas other than the vicinity of the end of the magnetic tape, the signal near the end of the magnetic tape remains true while retaining the function of completing the data transfer with the external device in a short time due to the provision of the buffer 2. If so, it is possible to accurately measure the remaining recordable capacity of the magnetic tape by actually performing a recording operation while temporarily suspending data transfer from the external device to buffer 2, and to use the obtained remaining capacity information. Equipped with a near-end recording protection function that determines whether a control command can be completed based on the detection accuracy of the near-end detector 4, the magnetic tape can contain scratches or other areas where digital data cannot be recorded correctly. Even if the data is stored in the external device, a response corresponding to a control command to an external device is not erroneously issued, and data can be recorded to the logical end while maintaining high initial data reliability. Moreover, since the logical end position can be specified with extremely high accuracy, data can be recorded in an area where reliability deterioration due to aging up to the logical end is extremely small, resulting in data recording that maintains high reliability over a long period of time. It is something that can be realized.

In addition, if the CPU 5 is equipped with a recording start protection function, it is possible to obtain capacity information prerecorded on the magnetic tape, or if valid remaining capacity information is obtained by the end-near-recording protection function, it is possible to Since it is determined whether the recording operation according to each control command can be completed, it is possible to realize an extremely smooth recording operation up to the logical end even if the tape is near the end, and data transfer with an external device in an extremely short time. Can be done. Moreover, even if the capacity information is erroneous, it is detected as being erroneous, and accurate remaining capacity information is measured again using the near-terminus recording protection function, so an erroneous response is never issued.

Finally, a digital data recording/reproducing apparatus according to a third embodiment of the present invention will be described. The configuration of the third embodiment is as follows.
Although the configuration diagram is the same as that of the second embodiment shown in the figure, the difference from the second embodiment is that the CPU 5 is equipped with a new end-near-record protection function.

The operation of the third embodiment of the present invention configured as described above will be described below. First, the capacity information acquisition unit 8 and the CPU 5 read the capacity information of the magnetic tape when the magnetic tape is mounted, and store the capacity information and remaining capacity information in the memory 9. Next, the CPU 5 receives a control command from an external device. However, if the control command requests a recording operation, the procedure of the recording start protection function is executed, and if the control command is not impossible to complete, the procedure of the near end recording protection function is started. Same as example.

FIG. 7 is a flowchart showing the procedure of the near-terminus recording protection function. The CPU 5 executes the processing procedure from step 101 to step 106 in FIG. The data transfer is temporarily interrupted and the process proceeds to step 301. When it is detected in step 301 that the recording of the digital data stored in the buffer 2 onto the magnetic tape is completed, in step 302 the end detector 10 is sent to the magnetic recording/reproducing section 3.
changes the instructions to perform a search operation until it detects the physical end of the magnetic tape.

The magnetic recording/reproducing section 3 increases the tape running speed and executes the above search operation while measuring the amount of tape running. CPU5
When the search operation of the magnetic recording/reproducing section 3 is completed, step 1 is performed.
In step 07, the information on the result of the search operation is received from the magnetic recording/reproducing unit 3, and in step 303, the recordable capacity of the area up to the physical end is calculated based on the travel distance of the magnetic tape in the search operation. , and the value obtained by subtracting the preset specified capacity, that is, the capacity that can be recorded up to the logical end position, is stored in the memory 9 as effective remaining capacity information. In steps 207 to 112, when the CPU 5 determines that the unrecorded portion of the recording capacity requested by the control command is less than the remaining amount information, the CPU 5 restarts the transfer of digital data from the external device to the buffer 2, and restarts the magnetic recording/reproducing unit. 3, the recording of the unrecorded portion is started, and further, when the data transfer from the external device is completed, a normal end response is issued and the procedure of the near-terminus recording protection function is ended.

Conversely, step 207. If it is determined in step 113 that the recording requested by the control command cannot be completed, an abnormal end response is issued. On the other hand, if the recording operation was not near the end of the magnetic tape, step 103. In step 104, when the recording operation ends normally or the data transfer from the external device to the buffer 12 is completed, a normal end response is output to the external device and the procedure of the near-end recording protection function is ended.

Since the procedure of the capacity information confirmation function is the same as that in the second embodiment, the explanation will be omitted.

As described above, according to this embodiment, in areas other than the vicinity of the end of the magnetic tape, the signal near the end of the magnetic tape remains true while retaining the function of completing the data transfer with the external device in a short time due to the provision of the buffer 2. If so, the remaining recordable capacity of the magnetic tape can be measured and calculated in a short time by performing a high-speed search operation while data transfer from the external device to buffer 2 is interrupted, and the obtained remaining capacity information can be used. Equipped with a near-terminus record protection function that determines whether a control command can be completed based on the detection accuracy of the close-to-terminal detector 4 prevents erroneously issuing a response corresponding to a control command to an external device, even if the detection accuracy of the near-terminal detector 4 is low. It is possible. Moreover, since the logical end position can be specified in an extremely short time, the recording operation is smooth, and data can be recorded in an area up to the logical end that is less likely to change over time.

In addition, the second. In the third embodiment, the end detector 10 is configured to detect the physical end by inspecting the output of the speed detector 6, but the end detector 10 detects the league tape, which is the physical end of the magnetic tape. It may also be configured to detect optically.

Effects of the Invention As described above, the digital data recording device of the present invention comprises: a communication means, a /< buffer for temporarily storing external data, a magnetic recording section for recording external data on a magnetic tape, a terminal vicinity detection means, Equipped with an end detection means for detecting the physical end of the magnetic tape, a remaining amount storage means, a recording start protection function that starts recording on the magnetic tape, and a recording protection function near the end, it is possible to perform normal recording. In operation, while retaining the ability to complete data transfer with an external device in a short time, it is possible to receive a normal completion response even when the detection accuracy of the near-end detection means is low or there are scratches on the unrecorded area of the magnetic tape. It is possible to reliably complete writing of digital data onto a magnetic tape while ensuring high reliability. In addition, by configuring the near-end detection means to consist of a speed detection means and a speed comparison means for the output reel of the magnetic tape, there is no need for a specially processed dedicated magnetic tape, making it highly versatile and inexpensive. We can supply magnetic tapes of various sizes. Furthermore, the microprocessor is equipped with a capacity information acquisition means for reading the capacity information from the magnetic tape and a capacity information storage means for storing the capacity information, and the microprocessor is equipped with a capacity information confirmation function to perform high-speed recording based on the capacity information. Although it is possible to control the operation, since an error is detected when the capacity information is an erroneous value greater than the actual capacity that can be recorded on the magnetic tape, no malfunction occurs. That is, since it is possible to realize a highly reliable digital data recording device using inexpensive magnetic tape while realizing high-speed data transfer, its practical effects are great.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the configuration of a digital data recording apparatus according to a first embodiment of the present invention, FIG. 2 is a flowchart of the same embodiment, FIG. 3 is a state diagram of a magnetic tape of the same embodiment, and FIG. The figure is a block diagram showing the configuration of a digital data recording apparatus in a second embodiment and a third embodiment of the present invention, FIG. 5 is a flowchart in the same embodiment, and FIG. 6 is a state of the magnetic tape in the same embodiment. 7 is a flowchart of the third embodiment, FIG. 8 is a block diagram showing the configuration of a conventional digital data recording apparatus, and FIG. 9 is a state diagram of the conventional magnetic tape. DESCRIPTION OF SYMBOLS 1...Communication part, 2...Buffer 3...Magnetic recording and reproducing part, 4...Terminal vicinity detector, 5.
...CPU. 6...Speed detector, 7...Speed comparator, 8
. . . Capacity information acquisition unit, 9 . . Memory, 10
... Termination detector.

Claims (6)

[Claims] (1) Communication means for transmitting and receiving external data and control commands transferred from an external device; a buffer for temporarily storing the external data; a magnetic recording section for recording the external data on a magnetic tape; and the magnetic tape. a near-terminus detection means that outputs true as a near-terminus signal when the near-terminus signal reaches the near-terminal end; and a microprocessor having a near-end recording protection function that restarts the receiving operation when the receiving operation is completed, and transmits a control command indicating the end of writing to the magnetic tape to the external device upon completion of the receiving operation. Characteristic digital data recording device. (2) a communication means for transmitting and receiving external data and control commands transferred from an external device; a buffer for temporarily storing the external data; a magnetic recording section for recording the external data on a magnetic tape; and the magnetic tape. a near-end detection means that outputs true as a near-end signal when reaching near the end of the magnetic tape, an end detection means that detects the physical end of the magnetic tape, and a remaining amount storage means that stores information on the remaining amount of the magnetic tape. , a recording start for starting a recording operation on the magnetic tape when the remaining amount information is invalid or the remaining amount information is valid and the recording capacity requested by the control command is less than or equal to the remaining amount; a protection function, and if the terminal proximity signal is true and the remaining amount information is invalid, the receiving operation of the communication means is stopped and the recording operation is continued until the terminal detection means detects the physical terminal. Then, a value obtained by subtracting a preset specified capacity from the capacity of normally recorded data is stored in the remaining capacity storage means as the remaining capacity information, and the capacity of unrecorded external data requested by the control command is stored. a microprocessor having a near-end recording protection function that restarts the reception operation if the remaining capacity information is less than the remaining amount information, and sends a response indicating completion of writing to the magnetic tape to the external device upon completion of the reception operation. A digital data recording device characterized by: (3) a communication means for transmitting and receiving external data and control commands transferred from an external device; a buffer for temporarily storing the external data; a magnetic recording section for recording the external data on a magnetic tape; and the magnetic tape. a search means for quickly searching for the magnetic tape; a near-end detection means for outputting true as a near-end signal when reaching near the end of the magnetic tape; an end detection means for detecting a physical end of the magnetic tape; remaining capacity storage means for storing remaining capacity information; and when the remaining capacity information is invalid or the remaining capacity information is valid and the recording capacity requested by the control command is less than or equal to the remaining capacity; a recording start protection function for starting a recording operation on the magnetic tape; and if the near end signal is true and the remaining amount information is invalid, the reception operation of the communication means is stopped and the data is stored in the buffer. recorded external data on the magnetic tape, executes a search operation until the end detection means detects the physical end, and subtracts a preset specified capacity from the searched capacity of the magnetic tape. is stored in the remaining amount storage means as the remaining amount information, and if the capacity of the untransferred external data is less than the remaining amount information, the receiving operation is restarted, and upon completion of the receiving operation, the data is transferred to the magnetic tape. A digital data recording device comprising: a microprocessor having a near-end recording protection function that transmits a response indicating completion of writing to the external device. (4) The magnetic recording unit includes a recording head, a reproduction head that reads the data from the magnetic tape immediately after recording the data with the recording head, and records data based on the data read by the reproduction head. a data reliability analysis unit that confirms the reliability of recorded data; and a recording control function that at least records the data again in a different area on the magnetic tape if the recorded data lacks reliability. The digital data recording device according to item 1, 2 or 3. (5) Near-end detection means that outputs true as a near-end signal when reaching near the end of the magnetic tape, and capacity information acquisition means that reads capacity information of the magnetic tape recorded at a preset position on the magnetic tape. and capacity information storage means for storing capacity information of the magnetic tape; the near-end signal is true and the total capacity of recorded data on the magnetic tape is within the range from the detectable position of the near-end detection means to the near-end signal. A digital data storage device comprising: a microprocessor having a capacity information confirmation function that invalidates the capacity information if the maximum capacity up to the end position of the magnetic tape is less than the value obtained by subtracting the capacity information from the capacity information. (6) The near-end detection means includes a speed detection means that detects the rotational speed of the sending reel of the magnetic tape, and a speed comparison device that outputs true as a near-end signal when the rotational speed becomes less than a preset specified speed. 6. A digital data recording device according to claim 1, comprising means.