JPH0293849A - Recording data transfer controller - Google Patents

Abstract

PURPOSE:To absorb interruption even when data to be transferred and outputted from a host computer are interrupted, and to shorten data processing time by temporarily storing the recording data, which are transferred and outputted from the host computer, and transferring the data with defining prescribed data quantity as data transfer unit. CONSTITUTION:The recording data to be transferred and outputted from a host computer 2 are temporarily stored to a storage part 13 and the recording data to be temporarily stored are transferred and outputted to a data recorder 1 with defining the prescribed data quantity as the data transfer unit. At such a time, in response to the data quantity which is temporarily stored to the storage part 13, the data quantity of the data transfer unit is variably set for the recording data which are transferred and outputted from the storage part 13 to the data recorder 1. Thus, even when the recording data to be transferred and outputted from the host computer 2 are interrupted in the middle of the data, the recording data can be continuously transferred to the data recorder 1 without any interval and the data processing time can be prevented from being unnecessarily prolonged.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Application Field) The present invention relates to a recorded data transfer control device for continuously transferring recorded data to a data recording device such as a magnetic tape device.

(Prior Art) A magnetic tape device used as an external storage device for a host computer writes recorded data transferred from the host computer onto a magnetic tape, and also reads data recorded on the magnetic tape and stores it in the host computer. Performs a series of data recording operations to be transferred. This type of magnetic tape device (device) is used by being directly connected to a host computer (host) 2, as shown in Fig. 4, and performs data recording operations under the control of the host computer 2. ing.

The magnetic tape device 1 sequentially records the recording data transferred from the host computer 2, but if an interruption occurs in the transfer of the recording data, it enters a standby operation. This standby operation involves mechanical movements, such as stopping the running of the magnetic tape, and generally lasts from the start of the standby operation until the standby operation is canceled (until the standby operation ends). Therefore, even if the transfer output of recorded data is resumed from the host computer 2 immediately after the start of the standby operation, the magnetic tape device 1 will not start the next recording until the series of standby operations is completed. There is a problem in that the host computer 2 cannot accept the data, and on the other hand, the host computer 2 has to wait for the transfer output of the recorded data until the standby operation in the magnetic tape device 1 is completed. In particular, when recording data is transferred piecemeal, the magnetic tape device 1 frequently performs standby operations, resulting in problems such as inability to perform constant and continuous data recording operations. For this reason, there is a problem in that waiting time is often required for the transfer and output of recording data from the host computer 2, and the data processing time is significantly increased.

(Problem to be Solved by the Invention) Conventionally, when recording data is transferred and output to a magnetic tape device, if there is an interruption in the transfer of the recorded data, the standby operation of the magnetic tape device is interrupted each time. As a result, the magnetic tape device cannot perform constant and stable continuous recording operations, and the host computer has to wait for the transfer output of recorded data, which significantly increases the data processing time. There was a problem.

The present invention has been made in consideration of these circumstances, and its purpose is to record data on a data recording device such as a magnetic tape device, regardless of whether or not there is an interruption in the transfer output of recorded data from a host computer. It is an object of the present invention to provide a recording data transfer control device that can realize a constant and stable recording operation by continuously transferring data.

[Structure of the Invention] (Means for Solving Problems) A recorded data transfer control device according to the present invention is interposed between a host computer and a data recording device such as a magnetic tape device, and Recorded data transferred and output from a computer is temporarily stored in a storage unit, and the recorded data temporarily stored in this storage unit is transferred and outputted to a data recording device in a predetermined amount of data as a data transfer unit,
At this time, the data amount of the data transfer unit of the recorded data to be transferred and outputted to the data recording device is variably set according to the amount of data temporarily stored in the storage section.

(Operation) According to the present invention, the amount of data in a data transfer unit of recorded data to be transferred and output from the storage section to the data recording device is determined according to the amount of data transferred from the host computer and temporarily stored in the storage section. Since the setting is variable, for example, if a large amount of data is temporarily stored, the data amount in the data transfer unit can be set to a large value, and if the amount of data stored in the storage unit is small, the data in the data transfer unit can be set to a large value. By setting the amount small, it becomes possible to continuously transfer recording data to the data recording device without interruption, and it is possible to effectively prevent the data recording device from shifting to standby operation.

As a result, even if there is an interruption in the data transferred and output from the host computer, the data recording device will continue to record data regardless of whether or not there is an interruption, and the data will be There is no need to wait for the transferred output. Therefore, it is possible to prevent the data processing time from increasing undesirably.

(Embodiment) Hereinafter, a recording data transfer control device according to an embodiment of the present invention will be described with reference to the drawings.

FIG. 1 is a schematic configuration diagram of an embodiment device. The recorded data transfer control device 3 according to this embodiment is a host computer (
A device interface 11. which is used by being inserted between the host) 2 and the magnetic tape device (device) 1, to which the magnetic tape device 1 is connected. A host interface 12 to which the host computer 2 is connected. Storage unit 1 consisting of a semiconductor memory that temporarily stores recorded data
3. and a control section 14 that controls the transfer of recorded data between the host computer 2 and the magnetic tape device 1 via the storage section 13.

The recording data transferred and output from the host computer 2 to the magnetic tape device l is taken into the recording data transfer control device 3 via the host interface 12,
The information is temporarily stored in the storage section 13 under the control of the control section 14 . The recorded data temporarily stored in the storage section 13 is read out in units of data transfer in predetermined amounts under the control of the control section 14, and is continuously transferred from the device interface 11 to the magnetic tape device l. It is to be transferred and output.

FIG. 2 schematically shows how data is written to and read from the storage section 13 under the control of the control section 14, and FIG. 3 is a diagram showing the flow of control processing procedures in the control section 14. be.

To explain the functions and actions of this device according to the flow of the control processing procedure shown in FIG. When a transfer request is given, the recorded data transferred and output from the host computer 2 is written into the storage section 13 (step b). Writing of this data is performed by controlling the write start address for the storage unit 13 according to the input pointer.

Specifically, at the beginning, the input pointer is in the storage unit 13.
Therefore, the recorded data transferred and output from the host computer 2 is as shown in FIG. 2(a).
As shown in FIG. 3, data is written in order from the first address of the storage unit 13. When the writing of the transfer data is completed,
The input pointer is moved to the address next to the final writing address, and the recorded data that is then transferred and output from the host computer 2 is written in the order starting from the address indicated by the input pointer at this time, that is, the data that has already been written. Data is written consecutively.

Note that the data written in the storage section 13 and transferred and output to the magnetic tape device I are sequentially erased on the storage section 13. When the data write position reaches the final address of the storage unit 13 due to movement of the input pointer, the data is continuously written by returning to the first address where data transfer and output has been completed.

In other words, writing and reading of data is controlled in the storage unit 13 so as to perform a FIFO (first-in, first-out) function, and its recording area is used cyclically.

When data is written to the storage section 13 in this manner, data is read from the storage section 13 in accordance with the output pointer as will be described later.

On the other hand, if a data transfer request is not given from the host computer 2, the control unit 14 determines whether data is stored in the storage unit 13 (step C).
. If no data is stored in the storage unit 13, the host computer 2 waits for a data transfer request, while if data is stored in the storage unit 13, the data is transferred from the storage unit 13. Execute transfer output control by reading. If data reading has already started, this data reading is performed by continuing reading that data according to the output pointer described above.

The data temporarily stored in the storage section 13 is read out and transferred to the magnetic tape device 1 in the following manner.

That is, data is read from the storage unit 13 using a predetermined amount of data as a data transfer unit, and is performed while controlling the data read start position according to the output pointer. in particular,
When data is temporarily stored in the storage unit 13 as shown in FIG. 2(a), the data is read out in predetermined data transfer units while advancing the output pointer as shown in FIG. 2(b), and is continuously transferred. The data is transferred and output to the magnetic tape device 1.

Note that the data transfer unit in which this data reading is performed is the amount of data remaining in the storage unit 13, that is, the data transferred from the host computer 2 and written in the storage unit 13, and is the amount of data remaining in the storage unit 13. It is variably controlled and determined as follows depending on the amount of data that has not been transferred or output. That is, when a large amount of data remains in the storage section 13, the amount of data in the data transfer unit is set large and that data is read, so that the amount of data remaining in the storage section 13 decreases. In this case, the amount of data in the data transfer unit is set small and the data is read.

By variable control of the amount of data in each data transfer unit, the temporarily stored data is transferred to the second
As shown in Figure (b), the data is first read out in data transfer units with a large amount of data set and transferred to the magnetic tape device L, and then as the remaining amount of data decreases, the data amount in the data transfer units is reduced. Read it out. This variable control of the amount of data per data transfer unit is performed so that data is transferred and output continuously to the extent that the magnetic tape device l does not perform standby operation.

Specifically, the amount of data in each data transfer unit is controlled by finding the difference between the input pointer and the output pointer, and determining from this difference how much data is left in the storage unit 13. (Step d). If the remaining amount of data is greater than the specified value [Th], the data amount in the data transfer unit is set larger (step e), and the data is read from the storage unit 13 in this unit and transferred to the magnetic tape device l. Transfer and output (step f).

In addition, if the remaining amount of data is less than the specified value [Thl, set the data amount of the data transfer unit to a smaller value (step g), data is read from the storage unit 13 using this as a unit, and the data is read from the magnetic tape. It is transferred and output to device l (step h). If the difference between the manual pointer and the output pointer disappears, this indicates that no data remains in the storage section 13, so reading of data from the storage section 13 is stopped, and new data is read from the host computer 2. Wait for data to be transferred.

According to this apparatus that performs such control, the amount of data in a predetermined data transfer unit that is transferred and output to the magnetic tape device l is varied according to the amount of data stored in the storage section 13. When the amount of remaining data is low, by reducing the amount of data in each data transfer unit, it is possible to extend the time of data transfer output by so-called data transfer, and to continue the data transfer output continuously. .

However, when the next new data is transferred from the host computer 2 during the period when the data transfer output is being enlarged, the data is stored in the storage unit 13 as shown in FIG. 2(C). be done. As a result, the remaining amount of data increases, so the data amount of the data transfer unit is set to be large again. Thereafter, such a control procedure is repeatedly executed.

Therefore, even if there is an interruption in the data transferred and output from the host computer 2, the data transfer time is expanded by variable control of the amount of data in the data transfer unit described above, so the interruption in the data can be absorbed. Transfer data can be made continuous. As a result, the magnetic tape device 1 does not go into a standby state due to data interruption, and it becomes possible to continuously record transferred data by a constant recording operation.

In addition, for the host computer 2, it becomes possible to transfer and output data without being aware of data interruptions, and since the magnetic tape device 1 does not go into a standby state, there is no need for involuntary waiting time. .

Therefore, the data can be continuously recorded on the magnetic tape device 1 without performing data transfer very efficiently.

Note that the present invention is not limited to the embodiments described above. For example, the amount of data as a unit of data transfer may be determined according to the data recording specifications of the magnetic tape device l. In addition, it is sufficient to determine how much data amount in a data transfer unit is to be varied as a control unit according to the specifications, and the point is to absorb minute interruptions in data transferred from the host computer 2. You just have to control it as much as possible. Further, even when data is output to a data recording device other than a magnetic tape device, the present invention can be similarly applied, and various modifications can be made without departing from the gist thereof.

[Effects of the Invention] As explained above, according to the present invention, even if there is an interruption in the data transferred and output from the host computer, it is possible to absorb this interruption and continuously transfer and output the data. Therefore, the data recording apparatus can perform a certain continuous recording operation without performing a standby operation. As a result, the data processing time can be shortened. Furthermore, for the host computer, since the data recording device does not perform standby operation, it is possible to transfer and output data without setting an undesired waiting time associated with this standby operation, thereby increasing the processing efficiency. This brings about great practical effects, such as making it possible.

[Brief explanation of the drawing]

FIG. 1 is a schematic configuration diagram of a recording data transfer control device according to an embodiment of the present invention, FIG. 2 is a diagram schematically showing the concept of data transfer control by the embodiment device, and FIG. 3 is a diagram of the embodiment device. FIG. 4, which is a diagram showing the control processing procedure, is a diagram for explaining the conventional data transfer output format and its problems. ■... Magnetic tape device (device), 2... Host computer (host), 3... Recorded data transfer control device, 11... Device interface, 12
... host interface, 13 ... storage section,
14...control unit.

Claims (1)

[Claims] a storage unit that temporarily stores recorded data transferred and output from the host computer; a data transfer output unit that transfers and outputs the recorded data temporarily stored in the storage unit to a data recording device in a predetermined data amount as a data transfer unit; The apparatus is characterized by comprising means for variably setting the amount of data in a data transfer unit of recording data to be transferred and output from the data transfer output section to the data recording device according to the amount of data temporarily stored in the storage section. recording data transfer control device.