JP2722744B2 - Digital data recording / reproducing device - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a digital data recording / reproducing apparatus using a tape.

2. Description of the Related Art At present, tape drive devices for recording and reproducing data from a host computer are commercially available. However, a data transfer speed between a head and a recording medium determined by a format on a tape, a tape feed speed, and the like; Alternatively, the data transfer speed between the host computer and the tape drive, which is determined by the capability of the application software, cannot always match. For this reason, a tape drive is provided with a buffer memory for the function of the buffer, but it cannot always be absorbed by the buffer memory.

If the data transfer speed of the host is faster than the data recording speed of the tape drive, the data will not be absorbed by the buffer memory sometime if data is sent continuously. A signal is sent to temporarily stop, and when a buffer becomes available, a signal is sent from the tape drive to the host to request data transfer. When the data transfer speed of the host is lower than that of the tape drive, the following two typical methods are used. One method is to adjust the data transfer speed by recording a gap that is invalid data without stopping the tape while waiting for data from the host, and the other is to stop the tape and wait until the next data is sent This is a so-called start-stop method.

Problems to be Solved by the Invention However, the buffer memory cannot be used indefinitely, and there is a problem that if a large buffer memory is used, the cost becomes high. The method of recording the gap on the tape and adjusting the data transfer speed has a problem that the consumption of the tape increases.The method of temporarily stopping the tape and waiting for the next data to be sent is to send the tape next. There is a problem that it takes a considerable amount of time to reach a predetermined speed at first.

In view of the above problems, it is an object of the present invention to provide a digital data recording / reproducing apparatus which can be configured with a small buffer capacity, consumes a small amount of tape in a gap area, and has a low frequency of temporarily stopping the tape.

Means for Solving the Problems In order to achieve the above object, a digital data recording / reproducing apparatus according to the present invention comprises a buffer use state management means for managing a use state of a buffer, and a memory for storing data stored in a buffer memory unit. Timer means for measuring the time during which the unit does not reach the state, or the actual feeling that the buffer full state in which no more data can be stored in the buffer memory unit continues,
If the data to be recorded is not in the buffer memory unit, the gap area is recorded by the recording / reproducing means, and when the time measured by the timer means reaches a preset value during recording, the recording medium is moved to the immediately preceding value. Control means for rewinding to the data recording area and then performing a recording operation following the data recording area after data is stored in the buffer memory unit; Recording / reproducing means having a mode for performing the data transfer, a speed switching means for switching the data transfer speed of the recording / reproducing means, and when there is no data to be recorded in the buffer memory section, the gap area is recorded by the recording / reproducing means. When the time measured by the timer means reaches a preset value, the data transfer speed of the recording / reproducing means is switched to one step lower, and the buffer full state is changed. When Ku case time measured by the timer means reaches a preset value, is obtained and a control means for switching the data transfer rate of the recording and reproducing means in one step faster.

Effect of the Invention With the above configuration, according to the above configuration, when data to be recorded is not in the buffer memory unit, the gap area is recorded by the recording / reproducing means, and the time measured by the timer means during recording is set to a preset value. When it reaches, the recording medium is rewound to the immediately preceding data recording medium by the instruction of the control means, and after the data is stored in the buffer memory unit, the recording operation is performed continuously to the data recording area.

Further, when there is no data to be recorded in the buffer memory section, the gap area is recorded by the recording / reproducing means, and when the time measured by the timer means reaches a preset value during the recording, The data transfer speed of the recording / reproducing means is switched to one step lower by an instruction, or when the buffer full state continues, when the time measured by the timer reaches a preset value, the recording / reproducing is instructed by the control means. The data transfer speed of the means is switched to the one higher by one step.

Embodiment An embodiment in which the digital data recording / reproducing apparatus of the present invention is applied to a rotary head type magnetic recording / reproducing apparatus will be described below with reference to the drawings.

FIG. 1 is a block diagram showing a configuration of a digital data recording / reproducing apparatus according to one embodiment of the present invention. This embodiment is applied to a so-called R-DAT digital data recording / reproducing apparatus in which two heads having different azimuth angles are rotated to form an oblique track on a tape and record digital data. .

In FIG. 1, 1 is a reel, 2 is a cylinder, 3a, 3b
Is a recording / reproducing head, 3c and 3d are reproducing heads for checking recorded data, 4 is a reel drive unit, and 5 is a cylinder drive unit. These are included in the mechanism unit 6. Reference numeral 7 denotes a mechanism control unit that controls the operation of the mechanism unit 6, and reference numeral 8 denotes a rotation speed control that is included in the mechanism unit 7 and that is connected to the reel driving unit 4 and the cylinder driving unit 5 and controls the rotation speed of the reel 1 and the cylinder 2. The unit 9 is connected to the heads 3a, 3b, 3c, 3d and sends a recording signal or receives a reproduction signal,
A signal processing unit for converting data and recording signals and performing error correction processing; 10 is an input / output device for receiving data from a host computer (not shown) and sending reproduced data to the host computer; 11 is an input / output device A buffer memory unit for temporarily storing data input to 10 and data for delivery to and from the signal processing unit 9; a buffer memory unit 12 included in the buffer memory unit 11 for managing a buffer use state; 13 is a buffer top register indicating the start address of the data stored in the buffer, 14 is a buffer end register indicating the last address of the data stored in the buffer, and 15 is a system for controlling the entire digital data recording / reproducing apparatus. Control unit, 16 is the system control unit 15
Is a clock switching unit that switches the clock of the signal processing unit 9 to switch the data transfer speed.

The operation of the digital data recording / reproducing apparatus configured as described above will be described below. First, a description will be given of an embodiment of the present invention that is effective when the data transfer speed of recording and reproduction is only one step.

Data input from the host computer to the input / output device 10 is temporarily stored in the buffer memory unit 11. Data is usually sent on a record or file basis. Where the sent data is stored in the buffer is managed by the addresses set in the buffer top register 13 and the buffer end register 14 in the buffer management unit 12. Information of the buffer top register 13 and the buffer end register 14 is sent from the buffer management unit 12 to the system control unit 15, and the system control unit 15 knows the capacity of stored data. A certain amount (for example, 128
When kilobytes of data are stored, the system control unit 15
Then, a recording operation instruction is issued to the mechanism control unit 7, and the instruction is given from the mechanism control unit 7 to the reel driving unit 4 and the cylinder driving unit 5 in the mechanism unit 6. On the other hand, data stored in the buffer memory unit 11 according to an instruction from the system control unit 15 is sent to the signal processing unit 9 after management data necessary for file management and the like is added, and error correction codes are added and modulated. The processing is performed, and the data is recorded on the tape through the heads 3a and 3b. As a data recording format using R-DAT, a format in which a third error correction code is added and recorded to improve reliability is currently proposed, but is omitted in this embodiment for simplicity of description. doing. In this embodiment, a fixed amount of data is recorded on a tape in a unit called a group as 128 kilobytes.

While one group is recorded on the tape in this manner, data to be recorded next is stored in the buffer memory unit 11 from the host computer through the input / output device 10, and is sequentially recorded on the tape. However, if the data transfer speed from the host computer is lower than the speed at which the data is recorded on the tape, after the data of a certain group is recorded, the data to be recorded next may not be stored in the buffer memory unit 11 yet. The processing procedure in the system control unit 15 in this case will be described with reference to the flowchart in FIG.

If it is confirmed in step 201 that the data recording process of one group has been completed, the process proceeds to step 202, where the timer unit 16 is reset. Next, the difference between the addresses indicated by the buffer top register 13 and the buffer end register 14 is calculated (step 203), and it is determined whether or not data of 128 kilobytes or more is stored (step 204). If 128 kilobytes or more of data has been stored, the process proceeds to step 210 as normal processing, and proceeds to processing for performing a recording operation. If it is less than 128 kilobytes, data from the host computer must be further waited, so that the signal processing unit 9 is instructed to record the gap area (step
205). In this embodiment, an R-DAT
In this method, a flag indicating a gap area is recorded in a portion called a subcode area for recording management information, which is located on a part of a track formed obliquely in a tape shape. Steps 203 to 206 are repeated until the timer reaches a predetermined value. If the data stored in the buffer memory unit 11 becomes 128 kilobytes or more in the middle of the timer, the process proceeds to the data recording processing of the group (step 210). And proceed. In step 206, it is determined whether the timer has reached a predetermined value (for example, 2 seconds). If the predetermined value is detected, an instruction to rewind the tape is output to the mechanism control unit 7 (step 207), the tape is rewound to the data area recorded immediately before, and the mechanism is stopped (step 208). . The process waits for data of 128 kilobytes or more to accumulate in the buffer memory unit 11 (step 209), and when data to be recorded is accumulated, proceeds to a recording operation process (step 210). As a result, the gap area having a length longer than the tape length corresponding to the predetermined time (2 seconds) is not formed.

Next, a description will be given of an embodiment of the present invention in the case where the data transfer speed of recording and reproduction has a mode of two or more stages.

First, a processing procedure in the system control unit 15 when the data transfer speed from the host computer is lower than the speed at which data is recorded on the tape will be described with reference to the flowchart in FIG. At first, the recording operation is performed at a preset data transfer rate, and the same processing as steps 201 to 206 described above is performed in steps 301 to 306, so that the description is omitted here. . If it is detected in step 306 that the timer has reached the predetermined value, the flow advances to step 307 to determine whether the current data transfer speed setting has reached the minimum speed. If the speed has not yet reached the minimum speed, the mode is switched to the mode one step lower, so that the system control unit 15 controls the rotation speed control unit 8 and the clock switching unit in the mechanism control unit 7.
An instruction is sent to 17 (step 308). For example, if an instruction to reduce the speed to 1/2 is sent, the rotation speed control unit 8 sends the reel driving unit 4 and the cylinder driving unit 5 to the reel driving unit 4 and the cylinder driving unit 5 such that the rotation speed of the reel 1 and the cylinder 2 becomes 1/2 of the specified rotation speed. Output instructions. Further, the clock switching unit 17 supplies a clock having a half frequency to the signal processing unit 9. As a result, the speed of reading the data of the signal processing unit 9 from the buffer memory unit 11 and the speed of outputting the data to the heads 3a and 3b are halved. Since both the tape feeding speed and the cylinder rotation speed are halved, the recording pattern on the tape does not change. Next, the process proceeds to step 302, and waits for more data to be recorded. From the next recording, the data transfer speed for recording and playback will be
It is slow as 1/2. Further, when it is necessary to reduce the data transfer rate for recording and reproduction, the processing from step 302 to step 308 is repeated, so that the data transfer rate suitable for the interface with the host computer is automatically selected. If the data transfer speed from the host computer is low even though the recording / reproducing minimum speed has been reached, the process proceeds to step 309, and the same processing as steps 207 to 210 described above is performed (steps 309 to 312). ).

Next, a case where the data transfer speed from the host computer is higher than the speed of recording on the tape will be described with reference to the flowchart shown in FIG.

In step 401, the system control unit 15 instructs the mechanism control unit 7 and the signal processing unit 9 to perform a recording operation, then resets the timer unit 16 and resets the flag S indicating that the data transfer speed needs to be switched. (Step 402).
During recording, the process proceeds to steps 403 and 404, where the buffer top register 13 and the buffer end register 14 are read, and it is determined whether or not the buffer is full based on the difference (step 405). When the buffer becomes full, a busy signal is output to the host computer to temporarily stop data input (step 406). If the buffer still has room, the busy is released and data input from the host computer is permitted (step 407). Next, the timer unit 16 is checked, and steps are taken until a predetermined value (for example, 2 seconds) is reached.
Steps 403 to 408 are repeated. If the recording is completed in the middle, the process passes through step 410 and proceeds to step 301 (third step).
It proceeds to the process of FIG. When the timer reaches a predetermined value, the process proceeds to step 409, sets a flag S indicating that the mode is switched to the next higher mode, and proceeds to step 403.
After the recording of the data of this group is completed, the flag S is determined in step 410, and if the flag is set, the mode is switched to the one-step faster mode. An instruction is sent to the control unit 8 and the clock switching unit 17 (step 411). For example, if an instruction to double the speed is sent, the rotation speed control unit 8 instructs the reel driving unit 4 and the cylinder driving unit 5 so that the reel 1 and the cylinder 2 have the double rotation speed as instructed. Output. Further, the clock switching unit 17 supplies a clock having a double frequency to the signal processing unit 9. As a result, the speed of reading the data of the signal processing unit 9 from the buffer memory unit 11 and the speed of outputting the data to the heads 3a and 3b are doubled. Since both the tape feeding speed and the cylinder rotation speed are doubled, the data recording pattern on the tape does not change. Thus, even when the transfer speed of the host computer is high, a data transfer speed suitable for the interface with the host computer is automatically selected.

Some of the mechanism control unit 7, the buffer management unit 12, and the system control unit 5 may be integrated into a microcomputer.

Effect of the Invention As described above, the present invention provides a buffer use state management unit that manages the use state of a buffer, a time period during which a state in which data stored in a buffer memory unit does not reach a recording unit continues, or Timer means for measuring the duration of the buffer full state in which no more data can be stored, and if there is no data to be recorded in the buffer memory section, the gap area is recorded by the recording / reproducing means. When the measured time reaches a preset value, the recording medium is rewound to the immediately preceding data recording area,
Next, after data is stored in the buffer memory unit, by providing control means for performing a recording operation continuously in the data recording area, useless gaps formed on the tape even when the data transfer speed from the host computer is low. It is possible to minimize the area and to reduce the frequency of the repositioning operation for returning the tape.

Still further, a recording / reproducing means having a mode for performing recording / reproduction at at least two stages of data transfer speed, a speed switching means for switching the data transfer speed of the recording / reproducing means, and The gap area is recorded by the recording / reproducing means, and when the time measured by the timer means during recording reaches a preset value, the data transfer speed of the recording / reproducing means is switched to one step lower, or When the full state continues, when the time measured by the timer means reaches a preset value, by providing control means for switching the data transfer speed of the recording / reproducing means one step faster, the interface with the host computer is provided. In this case, a data transfer rate suitable for the system is automatically selected, and an efficient system can be constructed. Further, the configuration can be such that the buffer capacity is small, and the effect is large.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of a digital data recording / reproducing apparatus according to an embodiment of the present invention, and FIG. 2 is a flowchart showing a control procedure of a system control unit when a data transfer speed of a recording / reproducing means is only one step. FIG. 3 is a flowchart showing a processing procedure in the system control unit when the data transfer speed of the recording / reproducing means has a mode of two or more stages and the data transfer speed from the host computer is lower than the speed of recording on the tape. FIG. 4 is a flowchart showing a processing procedure in the system control unit when the data transfer speed of the recording / reproducing means has a mode of two or more stages and the data transfer speed from the host computer is higher than the speed of recording on the tape. It is. 1 ... reel, 2 ... cylinder, 3a, 3b ... recording / reproducing head,
4 ... reel drive unit, 5 ... cylinder drive unit, 6 ... mechanism unit, 7 ... mechanism control unit, 8 ... rotation speed control unit, 9 ...
Signal processing unit, 10 input / output device, 11 buffer memory unit,
12: Buffer management unit, 13: Buffer top register, 14
... Buffer end register, 15 ... System control unit, 16 ...
Timer section, 17 ... clock switching section.

Claims (2)

(57) [Claims] An input device for externally inputting data; a buffer memory unit for temporarily storing input data; a buffer use state management unit for managing a use state of a buffer; and a data storage unit for storing data stored in the buffer memory unit. Recording and reproducing means for recording and reproducing on a recording medium and forming a gap area as an invalid data area on the recording medium; and a timer for measuring the time during which the data stored in the buffer memory unit does not reach the recording unit. Means for recording the gap area by the recording / reproducing means when the data to be recorded is not in the buffer memory section, and when the time measured by the timer means during recording reaches a preset value, recording is performed. The medium is rewound to the immediately preceding data recording area, and after the data is stored in the buffer memory unit, the data is continuously recorded in the data recording area. Digital data recording and reproducing apparatus characterized by comprising a control means for performing work. 2. An input device for externally inputting data, a buffer memory unit for temporarily storing input data, a buffer usage status management means for managing a usage status of a buffer, and recording at at least two stages of data transfer speed. A recording / reproducing means having a mode for performing reproduction, recording and reproducing data stored in the buffer memory unit on the recording medium, and forming a gap area on the recording medium as an invalid data area; Timer means for measuring a time during which a state in which data does not reach a recording unit or a time in which a buffer full state in which no more data can be stored in the buffer memory unit, and a speed switch for switching a data transfer rate of the recording / reproducing means Means, and if the data to be recorded is not in the buffer memory section, a gap is set by the recording / reproducing means. Area, and when the time measured by the timer means during recording reaches a preset value, the data transfer speed of the recording / reproducing means is switched to one step lower, or the buffer full state continues. When the time measured by the timer means reaches a preset value, the data transfer rate of the recording / reproducing means is set to 1
A digital data recording / reproducing apparatus, comprising: control means for switching to a step earlier.