JPH08315504A - Recorder and magnetic recorder - Google Patents

Abstract

PURPOSE: To shorten the time required for retrieval by providing a means for detecting the volume of data, a means for measuring the time and an operating means and recording the data through a recording means when the data write instruction is not given from a data source within an operated limit time. CONSTITUTION: Upon receiving a write command from an SCS 11/F member 14 with a logic block address(LBA) and a logic block number (LB) determined by a host computer as parameters, a CPU 13 returns a status and makes a transition to data out phase. At that moment of time, reception is inhibited temporarily in order to make ready for next step S102. The LBA is then converted into a physical write start address on an MD 1 and target heading address is calculated and stored. Furthermore a servo circuit 12 and the like are controlled while monitoring through a CD-ROM encoder/decoder 11 and an EFM encoder/decoder 10 to position an optical head 5 thus shortening the time required for reading.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a recording device and a magnetic recording device, for example. Specifically, when the data write command is not supplied from the data supply source within the time limit calculated by the calculation means, the recording means starts recording on the recording medium.

[0002]

2. Description of the Related Art Conventionally, data is input from an input device such as a keyboard, or data measured by a measuring device is supplied to a host computer so that the host computer processes the data. A magnetic recording device has been used as a means for recording and storing data processed by the host computer.

For example, there is a so-called tape streamer as a magnetic recording device for sequentially recording data processed by a host computer on a magnetic tape. FIG. 3 shows a block diagram of a conventional tape streamer. First, the structure of a conventional tape streamer will be described. In FIG. 3, the conventional tape streamer comprises a host interface unit 10 for interfacing data supplied from a host computer, a buffer memory 11 for temporarily holding data, and a formatter 12 for converting data into a predetermined data format. And a tape drive unit 13 for recording data on a magnetic tape and a system controller 14 for controlling these operations.

The conventional tape streamer configured as described above operates as follows. The host interface unit 10 includes, for example, a SCSI (Small computer
ystem interface) Data is supplied from the host computer via the interface. The form of the amount of data supplied from the host computer, the data transfer rate, the data interval, etc. is not constant.

The data supplied to the host interface section 10 is supplied to the buffer memory 11 and is once written in the buffer memory 11. Buffer memory 11
Is a FIFO memory, for example, which writes data on the one hand and at the same time reads data on the other hand.
When the amount of data written in the buffer memory 11 exceeds a certain amount, for example, when the maximum storage capacity of the buffer memory 11 is approached, the data written in the buffer memory 11 is supplied to the formatter 12. The storage capacity of the buffer memory 11 is determined by the effective data transfer rate required with the host computer and the servo characteristic (cycle time) of the tape drive unit 13. 1 /
In a high-speed and large-capacity tape streamer using a 2-inch tape or a 3 / 4-inch tape, the capacity of the buffer memory is as large as 16 megabytes to 128 megabytes.

The formatter 12 converts the supplied data into a specific file format. This file format corresponds to the format in which the tape drive unit 13 records data on the magnetic tape. Also,
The formatter 12 also performs data error correction processing. In this error correction processing, for example, an error correction code in a product code format using a Reed-Solomon code is applied to the data.

The data converted into a specific file format by the formatter 12 and subjected to the error correction code is supplied to the tape drive unit 13. In the tape drive unit 13, a magnetic tape is run by a tape running system motor or the like. Data processed by a recording preprocessing circuit or the like is recorded on the magnetic tape by a magnetic recording head.

The system controller 14 controls the operations of the host interface unit 10, the buffer memory 11, the formatter 12 and the tape drive unit 13. The system controller 14 exchanges SCSI commands for receiving data from the host computer with the host interface unit 10. The system controller 14 supplies the formatter 12 with control signals for file format processing and error correction processing. The system controller 14 supplies a control signal for driving the tape to the tape drive unit 13.

In this way, the data supplied from the host computer to the tape streamer is once written in the buffer memory 11 via the host interface section 10. Then, when a certain amount or more of data is accumulated in the buffer memory 11, the data is written on the tape through a file format process and an error correction process.

For such a tape streamer,
Generally, the host computer recognizes that the writing of data to the tape streamer is completed at the time when the host computer issues a write command to the host interface unit 10 and the data is transferred from the host computer to the host interface unit 10. To do.

However, in the tape streamer, actually, at this point, only the data is written in the buffer memory 11 and not yet written in the tape. The writing of data to the tape is started when a certain amount of data or more in the buffer memory 11 is accumulated. Controlling the buffer memory 11 in this manner is so-called that the amount of data supplied to the tape drive unit 13 exceeds the amount of data written to the tape for the time of the tape start and stop operations in the tape drive unit 13. This is to prevent the overhead phenomenon.

[0012]

However, if a problem such as a power failure occurs in the tape streamer in a situation where the data is only on the buffer memory 11, the buffer memory 1
There is a disadvantage that the data on No. 1 is lost and cannot be recovered.

Furthermore, the larger the capacity of the buffer memory 11, the larger the amount of data lost when a trouble occurs. In preparation for such a power failure, the buffer memory 11
Although it is conceivable to back up the power source of the above with a battery or the like, if the buffer memory 11 has a large capacity, the battery for backing up the power source also has a large capacity, and there is a disadvantage that it is impractical to provide this.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a recording apparatus having a high transfer rate and having a large capacity buffer memory, which is configured to reduce data loss when a trouble occurs. .

[0015]

A recording apparatus of the present invention includes a data amount detecting means for detecting the amount of data held in a storage means, a time point when a data write command is supplied from a data supply source, and a storage means. Corresponding to the time measuring means controlled based on the time when the recording means records the recorded data on the recording medium and the data amount detected by the data amount detecting means and the time measured by the time measuring means. And a calculation means for calculating a time limit for the recording means to start recording the data held in the storage means on the recording medium, and a data write command is issued from the data supply source within the time limit calculated by the calculation means. When not supplied, the recording means starts recording on the recording medium.

Further, the magnetic recording apparatus of the present invention comprises a data amount detecting means for detecting the amount of data held in the storage means,
A time measuring means controlled on the basis of a time point when the data write command is supplied from the data supply source and a time point when the operation of recording the data held in the storage means on the magnetic recording medium ends; And a calculating means for calculating a time limit for the magnetic recording means to start recording the data held in the storage means on the magnetic recording medium, corresponding to the amount of data detected by the detecting means and the time measured by the time measuring means. The magnetic recording means starts recording on the magnetic recording medium when the data write command is not supplied from the data supply source within the time limit calculated by the arithmetic means.

[0017]

According to the present invention, the following operations are performed. The data supplied from the data supply source is supplied to the storage means and is once written in the storage means. When the amount of data written in the storage means exceeds a certain amount, for example, when the maximum storage capacity of the storage means is approached, the data written in the storage means is supplied to the recording means. The data processed by the pre-recording process or the like is recorded on the recording medium by the recording means.

Here, the data amount detecting means, the time measuring means, and the calculating means operate as follows. The data amount detection means detects the amount of data in the storage means. As the data amount information, for example, the write address number and the read address number of the storage unit are received, and the data amount in the storage unit can be detected by obtaining the difference between the write address number and the read address number.

When a data write command is not issued from the data supply source to the recording device for a certain time limit or longer, the data is forcibly written to the recording medium. Calculate the time limit to start writing. Here, if this time limit is too long, there is a high possibility that trouble will occur during that time. On the contrary, if the time limit is too small, the writing operation to the recording medium will frequently occur, and the start and stop operations of the recording means will take some time. Becomes less efficient. For this reason, it is preferable that the time limit is not a fixed value but a value that becomes smaller as the amount of data in the storage means increases, in relation to the amount of data in the storage means.

The time measuring means is driven by a predetermined clock to measure time. The time measuring means is reset each time a data write command is received from the data supply source. Further, the time measuring means is reset every time the writing of the data to the recording medium by the recording means is completed.
In this way, the start of writing data to the recording medium by the recording unit is determined depending on whether or not the time measured by the time measuring unit is equal to or longer than the time limit.

As a result, when the command for instructing the data writing from the data supply source is not issued for a certain time limit or longer, the data is forcibly written in the recording medium.

Further, according to the present invention, the following operations are performed. The data supplied from the data supply source is supplied to the storage means and is once written in the storage means. When the amount of data written in the storage means exceeds a certain amount, for example, when the maximum storage capacity of the storage means is approached, the data written in the storage means is supplied to the magnetic recording means. The data processed by the pre-recording process or the like is recorded on the magnetic recording medium by the magnetic recording means.

Here, the data amount detecting means, the time measuring means, and the calculating means operate as follows. The data amount detection means detects the amount of data in the storage means. As the data amount information, for example, the write address number and the read address number of the storage unit are received, and the data amount in the storage unit can be detected by obtaining the difference between the write address number and the read address number.

When the data write command is not issued from the data supply source to the magnetic recording device for a certain time limit or longer, the data is forcibly written to the magnetic recording medium. Calculate the time limit to start writing data to. Here, if this time limit is too long, there is a high possibility that trouble will occur during that time. On the contrary, if the time limit is too small, the writing operation to the magnetic recording medium will frequently occur, and the start and stop operations of the magnetic recording means will take some time. The efficiency of the write operation becomes poor. For this reason,
It is preferable that the time limit is not a fixed value but a value that becomes smaller as the amount of data in the storage means becomes larger in relation to the amount of data in the storage means.

The time measuring means is driven by a predetermined clock to measure time. The time measuring means is reset each time a data write command is received from the data supply source. Further, the time measuring means is reset every time the writing of data to the magnetic recording medium by the magnetic recording means is completed. In this way, the start of writing the data to the magnetic recording medium by the magnetic recording means is determined depending on whether or not the time measured by the time measuring means is equal to or longer than the time limit.

As a result, when the command for instructing the data writing from the data supply source is not issued for a certain time limit or longer, the data is forcibly written to the magnetic recording medium.

[0027]

EXAMPLE In this example, the case where the present invention is applied to a tape streamer will be described. In this example, in particular, in the system controller, a data amount detecting means for detecting the amount of data in the buffer memory, and a time limit for starting writing data to the tape drive unit are calculated based on the amount of data in the buffer memory. The time limit calculating means and the write start determining means for determining the write start depending on whether the time measured by the timer is equal to or longer than the time limit are provided. As a result, when the host computer does not issue a data write command to the tape streamer for a certain time limit or longer, the data is forcibly written to the tape.

There is a so-called tape streamer as a magnetic recording device for sequentially recording data processed by a host computer on a magnetic tape. FIG. 1 shows a block diagram of the tape streamer of this example. First, the configuration of the tape streamer of this example will be described. In FIG. 1, a tape streamer of this example comprises a host interface unit 1 for interfacing data supplied from a host computer, a buffer memory 2 for temporarily holding data, and a formatter for converting data into a predetermined data format. 3, a tape drive unit 4 for recording data on a magnetic tape, and a system controller 5 for controlling these operations.

In particular, in this example, the data amount detecting means 7 for detecting the amount of data in the buffer memory 2 in the system controller 5 and the time limit for starting the writing of data to the tape drive unit 4 are set in the buffer memory 2. A time limit calculating means 8 for calculating based on the amount of data in the memory, a timer 6 operating with a predetermined clock, and a write start determining means 9 for determining the write start depending on whether the time measured by the timer 6 is equal to or longer than the time limit. And.

The tape streamer of this example constructed as described above operates as follows. Data is supplied to the host interface unit 1 from a host computer by, for example, a SCSI interface. The form of the amount of data supplied from the host computer, the data transfer rate, the data interval, etc. is not constant.

The data supplied to the host interface unit 1 is supplied to the buffer memory 2 and is temporarily written in the buffer memory 2. The buffer memory 2 is, for example, a FIFO, and writes data on one side and reads data on the other side. When the amount of data written in the buffer memory 2 exceeds a certain amount, for example, when the maximum storage capacity of the buffer memory 2 is approached, the data written in the buffer memory 2 is supplied to the formatter. The storage capacity of the buffer memory 2 is determined by the effective data transfer rate required with the host computer and the servo characteristic (cycle time) of the tape drive unit 4. In a high-speed and large-capacity tape streamer using 1/2 inch tape or 3/4 inch tape, the capacity of the buffer memory 2 is 16 megabytes to 128 megabytes.
It has a large capacity of megabytes. The buffer memory 2 supplies the system controller 5 with information regarding the amount of data stored in the buffer memory 2.

The formatter 3 converts the supplied data into a specific file format. This file format corresponds to the format in which the tape drive unit 4 records data on the magnetic tape. The formatter 3 also performs data error correction processing. In this error correction processing, for example, an error correction code in a product code format using a Reed-Solomon code is applied to the data.

The data converted into a specific file format by the formatter 3 and subjected to the error correction code is
It is supplied to the tape drive unit 4. Tape drive section 4
In, a magnetic tape is run by a tape running system motor or the like. Data processed by a recording preprocessing circuit or the like is recorded on the magnetic tape by a magnetic recording head.

The system controller 5 includes a host interface unit 1, a buffer memory 2 and a formatter 3.
It also controls the operation of the tape drive unit 4. The system controller 5 is an SC for receiving data from the host computer with the host interface unit 1.
Exchange SI commands. The system controller 5 receives the data amount information in the buffer memory 2.
The system controller 5 supplies the formatter 3 with control signals for file format processing and error correction processing. The system controller 5 supplies a control signal for driving the tape to the tape drive unit 4.

Here, in the system controller 5, the data amount detecting means 7, the time limit calculating means 8, the timer 6,
The write start determination means 9 operates as follows. The data amount detecting means 7 detects the amount of data in the buffer memory 2. As the data amount information, for example, the buffer memory 2
It is possible to detect the amount of data in the buffer memory 2 by receiving the write address number and the read address number and calculating the difference between the write address number and the read address number.

In this example, when the data write command is not issued from the host computer to the tape streamer for a certain time limit or more, the data is controlled to be forcibly written to the tape. , The time limit for starting writing data to the tape drive unit 4 is calculated. Here, if this time limit is too long, there is a high possibility that trouble will occur during that time. On the other hand, if the time limit is too small, frequent write operations to the tape will occur, and the tape start and stop operations will take some time. Becomes worse. For this reason, the time limit is not a fixed value,
Regarding the amount of data in the buffer memory 2, it is preferable that the value be smaller as the amount of data in the buffer memory 2 is larger.

The timer 6 is driven by a predetermined clock and measures time. The timer 6 is reset each time a write command is received from the host computer.
Further, the timer 6 is reset every time data writing to the tape drive unit 4 is completed. The write start determination means 9 determines the write start depending on whether the time measured by the timer 6 is equal to or longer than the time limit.

As a result, when the host computer does not issue a write command for instructing the tape streamer to write data for a certain time limit or longer, the data is forcibly written to the tape.

In this way, the data supplied from the host computer to the tape streamer is once written in the buffer memory 2 via the host interface section 1. Then, when a certain amount or more of data is accumulated in the buffer memory 2 or when the write command is not issued for more than a certain limit time, the data is
It is written on the tape through a file format process and an error correction process.

Here, the write command supplied from the host computer to the tape streamer includes both a normal data write command and a buffer flush command which is an instruction to forcibly write the data in the buffer memory 2 onto the tape. .

Therefore, there are the following three conditions for starting the writing of the data written in the buffer memory 2 onto the tape. This enables recording at a high transfer rate. Condition 1: When the capacity of the buffer memory 2 is N megabytes, the data in the buffer memory 2 is X megabytes (X <
N) or more. X is about 0.8N to 0.9N. Condition 2: When the buffer flush command is supplied from the host computer. Condition 3: The data in the buffer memory 2 is less than X megabytes (X <N), but the write command from the host computer is not issued for the time limit T seconds or more.

FIG. 2 shows a flowchart of the tape writing operation of this embodiment when the time limit T is variable.
When starting, the timer value is set to 0 in step S1 for initialization, and the time limit T is set to the maximum value T _max . The timer counts up with a predetermined clock independently of the processing flow. In step S2, the value of the time limit T is calculated from the data amount Y in the buffer memory 2. As described above, the data amount Y in the buffer memory 2
It is advisable to use a function in which the larger the value, the smaller the value of the time limit T. For example, if the minimum value T _min of the time limit T is the amount of data Y in the buffer memory 2
The time limit T can be calculated by the following function.

[0043]

## EQU1 ## T = (T _min −T _max ) Y / X + T _max

In step S3, the amount of data in the buffer memory 2 is detected. The amount of data Y in the buffer memory 2 is X
If the above conditions are satisfied, the above condition 1 is satisfied, so step S8
To start writing to the tape. When the tape writing operation is completed in step S9, step S7
, Timer value = 0, that is, reset, step S
Return to 1.

If the data amount Y in the buffer memory 2 is 0, immediately at step S7, the timer value = 0,
Return to step S1. Data amount Y in the buffer memory 2
Is larger than 0 and smaller than X, step S
Go to 4. In step S4, it is determined whether or not the timer value is larger than the time limit T.
Therefore, the write operation to the tape is started in step S8. When the tape writing operation is completed in step S9, the timer value = 0 is set in step S7, and the process returns to step S1.

When the timer value is smaller than the time limit T in step S4, it is determined in step S5 whether or not the flash command is supplied. When the flash command is supplied in step S5, the above condition 2 is satisfied, so the write operation to the tape is started in step S8. When the tape writing operation is completed in step S9, the timer value = 0 is set in step S7, and the process returns to step S1. If the flash command is not supplied in step S5, it is determined in step S6 whether or not the write command is supplied. When the write command is supplied in step S6, the timer value = 0 is set in step S7, and the process returns to step S1. When the write command is not supplied in step S6, the process directly returns to step S1.

In this way, condition 1: When the capacity of the buffer memory 2 is N megabytes, when the data in the buffer memory 2 becomes X megabytes (X <N) or more,
And condition 2: when a buffer flush command is supplied from the host computer, in addition to condition 3: the data in the buffer memory 2 is less than X megabytes (X <N), the write command from the host computer is restricted. When the data has not been issued for the time T seconds or more, the data written in the buffer memory 2 is started to be written on the tape, so that the data is left in the buffer memory 2 while being accumulated. Without limitation, when the amount of data in the buffer memory 2 is large, the time limit T becomes small, so that it is possible to prevent the data in the buffer memory 2 from being lost even when the power of the tape streamer fails. Further, when the amount of data in the buffer memory 2 is small, the time limit T becomes large, so that the writing operation can be efficiently performed without frequently repeating the tape start and stop.

As described above, since the time limit for writing data on the tape is set, when the data write command does not arrive within the time limit, the tape drive unit 4 automatically starts recording on the tape regardless of the command. It Therefore, it is possible to reduce the occurrence of a trouble in the tape streamer and the loss of all the data held in the buffer memory 2. Further, the time limit for the tape drive unit 4 to start recording the data held in the buffer memory 2 on the tape can be changed based on the amount of data held in the buffer memory 2. It is possible to improve the efficiency of the data writing operation to the tape by eliminating the waste of the recording operation to the tape.

In the above example, the tape streamer has been described, but it goes without saying that the present invention can be applied to other magnetic recording devices such as a normal VTR and a data recorder.
Further, in the above example, a tape is used as the recording medium, but in the magnetic disk recording apparatus, a recording medium such as a magneto-optical disk or a mini disk may be used.

[0050]

According to the present invention, the data amount detecting means for detecting the amount of data held in the storage means, the time when the data write command is supplied from the data supply source, and the data held in the storage means are recorded. The time measuring means controlled based on the time when the means finishes the recording operation on the recording medium, and the storage means corresponding to the data amount detected by the data amount detecting means and the time measured by the time measuring means. A recording means for calculating a time limit at which the recording means starts recording the data held in the recording medium, and when the data write command is not supplied from the data supply source within the time limit calculated by the calculating means, Since the recording means starts recording on the recording medium, the data stored in the storage means is recorded based on the amount of data stored in the storage means. There by providing the time limit for starting the recording on the recording medium, when the data write command does not come within the time limit, the recording medium is started by automatically recording means independent of instruction. Therefore, it is possible to reduce the occurrence of a trouble in the device and the loss of all the data held in the storage means. Further, the time limit for the recording means to start recording the data held in the storage means on the recording medium can be changed based on the amount of data held in the storage means. It is possible to improve efficiency of the data writing operation to the recording medium by eliminating unnecessary waste.

Further, according to the present invention, in the above,
The time measuring means is reset at the time when the data write command is supplied from the data supply source and when the recording means finishes the operation of recording the data held in the storage means on the recording medium, and counts up by a predetermined clock. Therefore, it is possible to measure the time from the time when the recording means ends the operation of recording the data on the recording medium to the time when the data write command is supplied from the data supply source.

Further, according to the present invention, in the above,
The calculation means calculates the time limit based on a function such that the larger the data amount detected by the data amount detection means, the shorter the time limit. Therefore, when the data amount held in the storage means is large, the storage means is stored. It is possible to reduce the time limit for the recording means to start recording the data held in the recording medium on the recording medium, and to reduce the loss of all the data held in the storage means due to the trouble of the apparatus. Conversely, when the amount of data held in the storage means is small, it is possible to increase the time limit for the recording means to start recording the data held in the storage means on the recording medium. It is possible to improve the efficiency of the data writing operation to the recording medium without frequently performing the recording operation to the medium.

Further, according to the present invention, in the above,
When the data write command is not supplied from the data supply source within the time limit calculated by the calculation unit, or when the amount of data held in the storage unit is close to the maximum storage capacity of the storage unit, or when the compulsory data write command is issued. Since the recording means starts recording on the recording medium when the recording medium is supplied from the supply source, the first recording start condition due to the absence of the data write command within the time limit, and
Since the recording operation to the recording medium by the recording means can be started based on the second recording start condition by the data amount stored in the storage means and the third recording start condition by the compulsory data writing command, It is possible to start recording on the recording medium by the recording means in consideration of the time limit in addition to the write command and the data amount.

Further, according to the present invention, in the magnetic recording device, the data amount detecting means for detecting the amount of data held in the storing means, the time when the data write command is supplied from the data supply source, and the storing means in the storing means. Time measurement means controlled based on the time when the operation of recording the recorded data on the magnetic recording medium by the magnetic recording means ends, the data amount detected by the data amount detection means and the time measured by the time measurement means Corresponding to the above, the magnetic recording means is provided with a computing means for computing a time limit at which the magnetic recording means starts recording the data on the magnetic recording medium, and a data write command is issued within the time limit computed by the computing means. When the data is not supplied from the data supply source, the magnetic recording means starts recording on the magnetic recording medium. By providing a time limit for the magnetic recording means to start recording the data held in the storage means on the magnetic recording medium based on the amount, when a data write command does not come within the time limit, it is automatically executed regardless of the command Then, recording is started on the magnetic recording medium by the magnetic recording means.
Therefore, it is possible to reduce the occurrence of a trouble in the device and the loss of all the data held in the storage means. Further, the time limit for the magnetic recording means to start recording the data held in the storage means on the magnetic recording medium can be changed based on the amount of data held in the storage means. By eliminating the waste of the magnetic recording operation to the magnetic recording medium, the efficiency of the data writing operation to the magnetic recording medium can be improved. .

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of a tape streamer of an embodiment of a recording device and a magnetic recording device of the present invention.

FIG. 2 is a flowchart showing the operation of another embodiment of the recording apparatus and the magnetic recording apparatus of the present invention.

FIG. 3 is a block diagram showing a configuration of a conventional tape streamer.

[Explanation of symbols]

 1 Host Interface Section 2 Buffer Memory 3 Formatter 4 Tape Drive Section 5 System Controller 6 Timer 7 Data Amount Detection Means 8 Time Limit Calculation Means 9 Writing Start Judgment Means

Claims (5)

[Claims] 1. Storage means for temporarily holding data supplied from a data supply source based on a data write command supplied from the data supply source, and data stored in the storage means in a predetermined data format. In a recording device including a recording unit that converts the data into a recording medium and records the data on a recording medium, a data amount detection unit that detects the amount of data held in the storage unit and the data write command are supplied from the data supply source. A time measuring means controlled based on a time point and a time point when the recording means records the data held in the storage means on the recording medium; a data amount detected by the data amount detecting means; The recording means records the data held in the storage means on the recording medium corresponding to the time measured by the time measuring means. A recording means for calculating a time limit to start, and when the data write command is not supplied from the data supply source within the time limit calculated by the calculation means, the recording means records the data on the recording medium. Recording device to start. 2. The recording apparatus according to claim 1, wherein the time measuring means records the time when the data write command is supplied from the data supply source and the data held in the storage means by the recording means. A recording apparatus, which is reset at the time of ending the operation of recording on a medium and counts up by a predetermined clock. 3. The recording apparatus according to claim 1, wherein the arithmetic means is based on a function such that the larger the data amount detected by the data amount detection means, the smaller the time limit. A recording device characterized by calculating. 4. The recording apparatus according to claim 1, wherein the data write command is not supplied from the data supply source within the time limit calculated by the calculation means, or the amount of data held in the storage means. Is close to the maximum storage capacity of the storage means, or when a compulsory data write command is supplied from the data supply source, the recording means starts recording on the recording medium. Recording device. 5. Storage means for temporarily holding data supplied from the data supply source based on a data write command supplied from the data supply source, and data stored in the storage means in a predetermined data format. In a magnetic recording device comprising magnetic recording means for converting the data into a magnetic recording medium for recording into a magnetic recording medium, a data amount detecting means for detecting the amount of data held in the storage means, and the data write command from the data supply source. Detected by the time measuring means controlled based on the time of supply and the time when the operation of recording the data held in the storage means on the magnetic recording medium ends, and the data amount detecting means The data stored in the storage means is recorded in the magnetic recording device in accordance with the amount of data recorded and the time measured by the time measuring means. A step for calculating a time limit for starting recording on the magnetic recording medium, wherein when the data write command is not supplied from the data supply source within the time limit calculated by the means, A magnetic recording device which starts recording on the magnetic recording medium by a magnetic recording means.