JPH08203215A - Data recorder - Google Patents

Abstract

(57) [Abstract] [Purpose] To improve the speed of the data writing process of the data recorder by improving the tape logical format. [Structure] The logical information of the last data is written in DIT, which is header information. This logical information is read when the tape is loaded and is held in the memory. When a data write request is made when additionally recording new data to the data already written on the tape, the logical information of the last data is acquired from the memory in step S11. Next, in step S12, logical information is added to the newly written data. Then, write this data and logical information on the tape. This eliminates the need to read the tape prior to writing.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a data recorder applicable to a helical scan type data recorder for recording digital data as oblique tracks on a magnetic tape by a rotary head.

[0002]

2. Description of the Related Art A magnetic tape device used as an external storage device such as a computer is known. As one of magnetic tape devices, a helical scan type device is known in which digital data is recorded on a cassette tape by a rotary head. Such a magnetic tape device is a large-capacity device, and when recording data, it is unlikely that the previous data is crushed and written. In most cases, the previous data is additionally recorded and the data history is taken. Often.

In addition, it is usual to maintain the continuity of physical addresses and / or logical addresses between already written data and newly written data. At the end of the recorded data of the conventional magnetic tape device, EOD (End Of Data) indicating that it is the end of the already written data
Is recorded. At the time of recording, the logical information of the data already written using this EOD is read from the tape,
The logical information having continuity is added to the data to be recorded based on the read logical information, and
It recorded the data and the added logical information.

[0004]

As in the conventional data recorder, when the logical information of the already written data is read from the tape before the writing and the logical information is added to the data to be recorded, the tape is recorded. The read operation from causes the write operation to slow down, and
There was a problem that the tape had to be read each time it was written, and the tape was damaged.

Therefore, an object of the present invention is to provide a data recorder in which the speed of writing operation is improved and the risk of damaging the tape is reduced.

[0006]

SUMMARY OF THE INVENTION The present invention relates to a data recorder for sequentially writing digital data on a tape-shaped recording medium, the last data among the data already recorded on the tape-shaped recording medium. Has the logical information of as header information, the header information is acquired and held when the tape-shaped recording medium is mounted, and when writing new data, based on the logical information in the held header information,
It is a data recorder in which logical information is added to new data and the new data and the added logical information are written.

[0007]

By the loading process when the tape is loaded, the logical information (physical address and / or logical address) of the data recorded last on the tape is read and held in the memory. Therefore, at the time of writing, by referring to this logical information (that is, without reading the data from the tape), the logical information can be added to the data to be newly recorded.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Prior to the description of one embodiment of the present invention, a data recorder to which the present invention can be applied will be described. The data recorder described here records / reproduces digital data on / from a cassette tape with a rotary head. 1 and 2 show the front and back of the exterior of the device, respectively.

As shown, two units stacked one above the other, namely a tape drive controller 1
And the digital information recorder 2 constitute a data recorder. The front panel of the tape drive controller 1 is provided with a button 3 for operating loading / unloading of the cassette tape, and a plurality of light emitting diodes 4 for indicating whether or not the cassette tape is loaded, a power-on state and the like. There is. A cassette tape insertion slot 5 is provided on the front panel of the digital information recorder 2. Further, other operation buttons are also arranged on the portion covered by the openable / closable panel 6.

As shown in FIG. 2, a plurality of connectors are provided on the back surface of each of the tape drive controller 1 and the digital information recorder 2. The lower tape drive controller 1 includes a data input / output connector 11, a control connector 12, and an RS232.
A C connector 13, two SCSI connectors 14a and 14b, an AC power supply input connector 15, and a DC power supply output connector 16 are provided.

On the other hand, the digital information recorder 2 is provided with a data input / output connector 21, a control connector 22, and an RS232C connector 23. The operating power of the digital information recorder 2 is supplied by connecting a connection cable to the DC power output connector 16 of the tape drive controller 1. The data input / output connectors 11 and 21 are connected by a cable, and the data flow is transmitted and received between the controller 1 and the recorder 2.
The control connectors 12 and 22 are connected by a cable to exchange control signals. further,
The RS232C connectors 13 and 23 are provided for diagnosis.

As shown in FIG. 3, the host computer 2
When connecting 0 and the data recorder, the SCSI connectors 14a and 14b are used. When the host computer 20 gives a read command to the data recorder, for example, the data recorder outputs the data to the host computer 20.

The digital information recorder 2 records / reproduces digital data on / from a cassette tape with a rotary head. FIG. 4 shows an example of the head arrangement of the recorder 2. Drum 2 rotating at a predetermined speed in the direction shown
Four heads Ra, Rb, Rc and Rd for recording and four heads Pa, Pb, Pc and Pd for reproduction are attached to the disk 5, respectively.

The heads Ra and Rb are provided in close proximity to each other, and similarly, the heads Rc and Rd, the heads Pa and Pb, and the pair of heads Pc and Pd are provided in close proximity to each other. Further, the extension direction (called azimuth) of the gap between these two adjacent heads is different. Heads Ra facing each other at 180 ° intervals
And Rc has a first azimuth, similarly 180 °
Heads Rb and Rd facing each other at a distance of 2 have a second azimuth. The heads Pa and Pc have the first azimuth, and the heads Pb and Pd have the second azimuth. The different azimuths are used to prevent crosstalk between adjacent tracks. The two adjacent heads are actually realized as an integrally structured head called a double azimuth head.

A tape (for example, ½ inch width) pulled out from the cassette is obliquely wound around the peripheral surface of the drum 25 over an angular range slightly larger than 180 °. The tape is fed at a predetermined speed. Therefore, at the time of recording, in the first half of the period in which the drum 25 makes one rotation, the head Ra
And Rb scan the tape, and in the latter half, the heads Rc and Rd scan the tape. During playback, the head Pa
And Pb scan the tape, then heads Pc and Pd scan the tape.

FIG. 5 shows a track pattern on the tape of the digital information recorder 2. Longitudinal tracks are formed on the upper and lower sides of the tape in the width direction, and helical tracks are formed between them. Upper longitudinal track 2
A control signal is recorded in 6 and a time code is recorded in the lower longitudinal track 27. The time code indicates the longitudinal position of the tape,
For example, SMPTE time code is used. Drum 2
In one rotation of 5, the heads Ra and Rb simultaneously form two helical tracks Ta and Tb, and then the heads Rc and Rd simultaneously form two helical tracks Tc and Td. It should be noted that each helical track is formed by separating the first half portion and the second half portion, and a tracking pilot signal recording area 28 is provided in the middle portion.

The SMPTE time code was developed for a video signal such as a VTR, and its minimum unit is a frame (1/30 second). As will be described later, the data recorder has four tracks Ta to Td shown in FIG.
Is a logical data unit of data (referred to as a track set) that handles recordable data. For example, in the case where 16 tracks correspond to one frame of a video signal, the lower digit (value of 0, 1, 2, or 3) of the digit of the frame of the time code is provided and the track set is set as a unit. It is necessary to use a time code (also referred to as an ID) to be used. In case of SMPTE time code,
Since the user data area is prepared, this kind of modification is possible.

FIG. 6 schematically shows a system configuration of the tape drive controller 1 and the digital information recorder 2. System controller 31 in controller 1
The main features of are: Management of SCSI controller 32 Management of buffer memory 33 File management / table management Data writing, reading, retry management Digital information recorder 2 control Self-diagnosis

A connection with the host computer is made via the SCSI controller 32. Buffer memory 33
A drive controller 34 is provided between the tape controller and the tape drive controller. The data read from the buffer memory 33 is supplied to the C2 encoder 35 via the drive controller 34. C2 encoder 3
5 to the track interleave circuit 36 and C1
The encoder 37 is connected.

The C2 encoder 35 and the C1 encoder 37 are for performing error correction coding of the product code on the recording data. Further, the track interleave circuit 36 controls distribution of data to tracks when recording data in order to improve the ability to correct errors that occur in the recording / reproducing process.

Further, when recording data on the tape, since the SYNC block divided by the sync signal is used as a unit, the block interleave circuit 36 adds the block sync signal. Further, in the C1 encoder 37, after the C1 parity is generated, data randomization and word interleaving processing in a plurality of SYNC blocks are performed.

The digital data from the C1 encoder 37 is transmitted to the digital information recorder 2. The digital information recorder 2 includes a channel code encoder 38.
The digital data received in step 3 is encoded, and the print data is output to the print heads Ra to Rd via the RF and amplifier 39. Recording data is recorded on the tape by the heads Ra to Rd. The RF / amplifier 39 processes the partial response class 4 (PR (1,0, -1)).

The data reproduced from the tape by the reproducing heads Pa to Pd is supplied to the channel code decoder 42 via the RF and amplifier 41. RF, amplifier 41
Includes a reproduction amplifier, an equalizer, a Viterbi decoder, and the like.
The output of the channel code decoder 42 is transmitted to the tape drive controller 1 and input to the C1 decoder 43.

A track deinterleave circuit 44 is connected to the C1 decoder 43, and a C2 decoder 45 is further connected to the deinterleave circuit 44. The C1 decoder 43, the track deinterleave circuit 44, and the C2 decoder 45 respectively include a C1 encoder 37, a track interleave circuit 36, and a C2 encoder.
A process opposite to the process performed by each of the encoders 35 is performed. The reproduction (read) data from the C2 decoder 45 is transferred to the buffer memory 33 via the drive controller 34.
Is supplied to.

The digital information recorder 2 is provided with a system controller 46. Also, a fixed head 47 is provided for the tracks in the longitudinal direction of the tape,
The head 47 is connected to the system controller 46, and the head 47 records / reproduces a control signal and a time code. The system controller 46 is connected to the system controller 31 of the tape drive controller 1 via a bidirectional bus.

A mechanism controller 48 is connected to the system controller 46. The mechanism controller 48 includes a servo circuit and drives a motor 50 via a motor drive circuit 49. The system controller 46 has, for example, two CPUs, communicates with the tape drive controller 1 and records / records time codes.
The system controller 46 controls reproduction, recording / reproduction timing, and the like.

The mechanism controller 48 is, for example, 2
It has CPUs and controls the mechanical system of the digital information recorder 2. More specifically, the mechanism controller 48 controls header / tape system rotation control, tape speed control, tracking control, cassette tape loading / unloading control, and tape tension control. The motor 50 generally represents a drum motor, a capstan motor, a reel motor, a cassette mounting motor, a loading motor, and the like.

Further, DC to which the DC voltage from the power supply unit 51 of the tape drive controller 1 is input
A -DC conversion circuit 52 is provided. Although not shown in the figure, the digital information recorder 2 includes a position sensor such as a tape end detection sensor and a time code generator /
A reading circuit and the like are provided.

Next, the format for recording digital data will be described. First, the layout of the entire tape (for example, the tape in one cassette) is shown in FIG. The entire tape is a physical volume. A physical tape beginning PBOT (Physical Beginning of Tape) and an end P to which a leader tape is connected.
Areas that can be recorded between EOT (Physical End of Tape) are LBOT (Logical Beginning of Tape) and L
It is between EOT (Logical End of Tape). This is because the tape is easily damaged at the beginning and end of the tape and the error rate is high. As an example, the invalid area between PBOT and LBOT is defined as 7.7 ± 0.5 m, and the invalid area between PBET and LBET is 10
Specified as greater than m.

In order to manage one or more logical volumes (also called partitions), VSIT (Volume Set Information Table) is recorded at the beginning of the recording area. VSIT has the number of volumes recorded on the tape and position information of each logical volume on the tape.
The position information is the physical ID of each VIT of the maximum 512 logical volumes, the final physical ID, and the logical ID of the VIT.
Is. Further, the flag indicating the presence / absence of UIT of each logical volume is also included in VSIT.

The position of the beginning of VSIT is the position of 0-ID. The ID is an address corresponding to a position on the tape that is assigned to each set of four tracks. From the VSIT area to the DIT area of the last volume, the ID is added monotonically. The length of one VSIT is 1-ID
Is.

A logical volume is a DIT (Directory Inf
ormation table), UIT (User Information Table) and user data area. The DIT has information for managing files in the logical volume. The length of one DIT is 40-ID. UIT is optional. UIT is user-specific information for managing files.

In FIG. 7, the hatched area is a run-up area. The data track is servo-locked by the run-up area. The area with dots is a position margin band. This position margin band prevents erasing valid data when VSIT and DIT are updated.

VSIT is repeatedly recorded 10 times as shown in FIG. 8A in order to improve the reliability of data. Therefore, the VSIT area is 10 track sets (= 10-ID). 90 after the VSIT area
A retry area larger than the track set is secured.

The DIT is repeatedly recorded seven times as shown in FIG. 8B in order to improve the reliability of the data. The DIT is composed of 6 tables as shown in FIG. 8C. The six tables are
T (Volume Information Table), BST (Bad Spot Tabl)
e), LIDT (Logical ID Table), FIT (File Inform
application table), UT (Update Table), UIT (User Info)
rmation Table). VIT, BST, LIDT, U
T has a length of 1-ID and FIT has a length of 20-ID. The remaining 16-ID area is reserved.

Each table of DIT will be described. V
The IT ID address is the top physical ID of the volume written in VSIT, and its logical ID is VSI.
It is the head logical ID of the volume written in T. V
The IT includes volume position information such as the volume label, the starting physical ID of the first data block in the physical volume, and the last physical ID thereof.

The ID address of BST is the physical I of VIT.
D + 1 and its logical ID is VIT logical ID + 1
Is. The BST contains logically invalid data information.
Logically invalid data is data that should be treated as invalid because data having the same track set ID is written later. For example, as shown in FIG. 9, the shadow area A is logically invalid data. The write retry operation and the write operation associated with it cause logically invalid data. If an error occurs during writing, write retry is automatically performed, the error location is output, and this is registered in BST. Then, during the read operation, the invalid area is designated by the BST. Data that is logically invalid is also called a bad spot. The BST manages start physical IDs and end physical IDs of up to 14592 bad spots.

The ID address of the LIDT is the physical ID of the VIT + 2, and its logical ID is the logical ID of the VIT +
It is 2. LIDT is a data table for fast block space and locate operations.
That is, the logical ID of each pointer of the first to 296th pointers, its physical ID, file number, I
The first block number in the D data block management table is included in the LIDT.

The ID address of the FIT is the physical I of the VIT.
D + 3, and its logical ID is VIT logical ID + 3
Is. The FIT is composed of two types of data pairs corresponding to the tape mark. The tape mark is the delimiter code of the file. The Nth data pair corresponds to the Nth tape mark from the beginning of the volume. One data of the pair is the physical ID of the Nth tape mark. This value is the physical track set ID of the tape mark
Is. The other data is the absolute block number of the Nth tape mark. This value is the absolute block number of the last block with the same file number as the tape mark. Since the position of the tape mark is known, the physical position on the tape can be accessed at high speed.

The ID address of the UT is the physical ID of the VIT
It is +39. UT is information indicating whether or not the volume has been updated. Before the update, the word (4 bytes) indicating the update status in the UT is FFFFFFFFh.
(H means hexadecimal), and after updating, this is set to 00000000h.

UIT is an optional area, for example, an area of 100-ID. It is a data table accessible to the user and is reserved for the user header.

In this example, 1-ID is assigned to each track set consisting of four helical tracks. The logical structure of the data block is defined for each track set. FIG. 10 shows a logical track set structure. The first 4 bytes of the logical track set is the format ID, which is FFFF0000h.

The next 136 bytes (34 words) is an area for subcode data. The subcode data consists of management information of the related track set. For example, the ID of the above-mentioned table (VSIT, VIT, BST, etc.)
Is included in the subcode.

Further, the number of bytes obtained by removing the length of the block management table from the next 116884 bytes is the user data area. If the size of the user data does not reach the specified size, the dummy data is packed in the remaining area. The formats of the track sets defined in the user data area include user track sets, tape mark (TM) track sets, and EOD (End Of Da).
ta) There are four types: track set and dummy track set. A subcode and a block management table are defined for each format of these track sets.

A block management table area is provided after the user data area. The block management table is
The maximum length is 4096 bytes. The last 4 bytes of the track set are the end code of the track set (0F0
F0F0Fh), and the previous 12 bytes are reserved. The block management table manages the data block configuration of user data.

The logical format of the above data recorder is shown in FIG. VSIT is recorded for each physical volume such as one tape. A DIT is recorded for each logical volume (partition), and five tables VIT, BST, LIDT, and FI are recorded in the DIT.
T, UT are included, and UIT is optionally included. In addition, a track set is defined for each four Heliel tracks, and four types of user track sets, a tape mark track set, an EOD (End Of Data) track set, and a dummy track set are defined in the user data area in the track set. To be done.

Now, an outline of the operation of the above data recorder will be described. First, when using the first tape, it is necessary to initialize the tape. In the tape initialization operation, VSIT, DIT, and EOD are written in predetermined positions, and dummy data are written.

When reading / writing a tape is started,
The tape is loaded. After the tape is inserted, the button 3 is pressed to perform the loading operation. VSIT and D when loading
IT is read. When the reading / writing of the tape is finished, the tape is unloaded by pressing the button 3. VSIT and DIT are rewritten when unloading. The load operation and the unload operation can be performed by a command other than the operation of the button 3.

FIG. 12 shows the tape drive controller 1
The system configuration of is shown in more detail. 61 is the main CP
U, 70 are 2-port RAMs, 80 is a bank memory, and 81 is a sub CPU. The main CPU 61 is a CPU that manages the entire system. A CPU bus 62 is provided in association with the main CPU 61, and each component is coupled to the CPU bus 62. That is, ROM (flash ROM) 63, PIO (parallel I / O) 65, control panel 66, LCD 67, timer 68, R
S232C interface 69, 2-port RAM7
0, the RAM 71 is connected.

The PIO 65 is connected to the buttons on the front panel. The LCD 67 is a display device that displays the operating status of the drive so that the user can see it. RS2
The 32C interface 69 is connected to the serial terminal. The RAM 71 is a work R used by the firmware.
It has an AM, a program download area, and an area for temporarily storing header information (VSIT / DIT).

Unidirectional control element 7 for CPU bus 62
The IM bus 74 is connected via the terminal 3. This IM bus 7
4, S-RAM 72, bank memory 80, SC
The SI controller 75 is connected. A host computer is connected to the SCSI controller 75 via a bus 76. The S-RAM 72 is a capacitor backup RAM, a script RAM, and a memory that actually holds logger data. This memory can hold data for about two days after the power is turned off.

The two-port RAM 70 has two CPUs 6
Five types of packets for communication of information between 1 and 81 are stored. These are: Command transmission packet: a packet used when requesting the CPU 61 to 81 to execute an operation. End status reception packet: a packet used for notifying the end status when the CPU 81 executes a command requested by the CPU 61 and the operation ends. Command status; a flag for indicating the progress of the command. Drive management status table; drive status is C
This is a table for notifying the PU 61. This table is rewritten by the CPU 81 at regular intervals. Data transmission / reception packet; a buffer used when the firmware on the drive (recorder) side is downloaded via the SCSI bus, or when the drive side diagnostic is activated using the serial port of the CPU 61. The bank memory 80 is a buffer memory for data.

The sub CPU 81 is a CPU for controlling the drive. CPU bus 8 associated with sub CPU 81
2 is provided, and a ROM (flash RO
M) 83, RAM (work RAM) 84, timer 8
5, RS232C interface 86, RS422 interface 87, PIO (processor control) 88, and DMA controller 89 are connected, and further, 2-port RAM 70 and bank memory 80 are connected.

The bank memory 80 is a bank memory for storing data on the tape. For example, the bank memory 80 has eight memory banks, and write data or read data is stored here. A DMA (Direct Memory Access) controller 89 is a controller for pasting the data written in the drive to the bank memory 80. RS232C interface 86
Is for diagnostics. The RS422 interface 87 is a communication means with the drive.

In order to facilitate the understanding of the present invention, the write operation by the previously proposed data recorder described above will be described with reference to FIG. Since the data recorder is a sequential access device, the normal write sequence is additional recording. That is, at the time of writing, first, the data is moved to the last position where the data is already written, and then the data is written on the tape, and the tape mark (TM) is added.

As shown in FIG. 13A, the user data is T
Consider a case where writing is performed on a tape that has already been recorded with M as a delimiter. First, when the SCSI controller 75 receives a SPACE EOD (moving written data to the end) request from the host computer,
From the data in the RAM 71, the main CPU 61 recognizes data relating to EOD, for example, position information of the EOD on the tape.

When the SCSI controller 75 receives a write (write user data) request from the host computer, as a preparation, as shown in FIG. 13B, the last (EOD) 10-ID before the written data is read. Pre-roll to position, then 10-ID from that position
Read the data. This read operation is necessary for obtaining the logical information of the data already recorded on the tape and for searching the tape break. Then E
Pre-roll to the OD position. Further, the SCSI computer 75 pastes the data from the host computer in the bank memory 80. In addition, the main CPU
61 creates one user data block management table in the bank memory 80.

Further, the write FM (file mark = tape mark writing) from the host computer is SC
When the SI controller 75 receives it, it moves to the next ID (track set) created above and creates a tape mark track set. Then, as shown in FIG. 13C, new user data is additionally recorded. Then, as shown in FIG. 13D, the tape mark TM is written immediately after the new user data. In this way, new user data is recorded.

The above write operation will be described in more detail.
At the time of writing, a write command is issued from the host computer. As a process, data is secured in the bank memory 80 and a subcode and block management table are created. FIG. 14A shows the data in the memory area in the bank memory 80. This shows a state in which a subcode, user data, and a block table (total 1-ID) are stored.

Then, from the host computer, write F
The M (write file mark) command is issued.
In response to this, it moves to the next ID and the track mark TM
1-ID is created, and the tape mark TM is created as the next ID, as shown in FIG. 14B. The content of the user data of the tape mark TM is not fixed.

The data thus created and stored in the bank memory 80 is written on the tape. This operation is shown in FIG. 14C. That is, if the start position of additional recording is II, the position 10-ID before that is indicated by I,
The position of the tape mark TM is indicated by III. As a limitation on the tape format, the minimum unit of writing is 10-I.
It is defined as D. Therefore, it is actually the most efficient to write data from position II, but I to II (10-
If there is a break (previous writing start point) in the previously written data during (ID), it is necessary to shift the writing start point backward from the position II. Furthermore, since it is necessary to acquire the file number, block number, and logical ID for the user ID, it is necessary to read the ID before II.

The writing process of the previously proposed data recorder will be described with reference to the flowchart of FIG.
In step S1, the data in the range I to II is read from the tape. The latest logic I in the read data
D, the file number, and the block number are searched from the back, and these are acquired. Then, a logical ID, a file number, and a block number are attached to the data in the memory (step S3).

In the next step S4, it is checked whether there is a previous write start point between I and II. Young
If there is no writing start point, control moves to step S5,
Writing starts from position II. If there is a writing start point, writing is started from a position 10-ID away from the previous writing start point (step S6). Then, in step S7, the position of III (that is, the position of the tape mark) is reflected in the FIT.

In the next step S8, it is checked whether either the user or the tape mark is (logical ID% 200) = 0. If so, tell the LIDT that I
After reflecting D (step S9), the process ends. . If not, the process ends.

FIG. 16 shows the contents of the subcode area in the previously proposed data recorder. The subcode contains words from 0 to 33. For example, word 1 is a logical ID. The logical ID is for identifying what the data area means (user / tape mark TM / dummy / EOD, etc.). Word 2 is the file number. The file number is a number consecutively assigned from 0 to the files defined in the logical volume.

FIG. 17 shows the contents of the block management table in the previously proposed data recorder.
A block management table is formed every four words. Word 0 is the absolute block number. This manages the number of logical blocks from the beginning of the volume. Word 1 is the head position of the data area, and it manages from which address in 1-ID the reference is made. Word 2 is the number of valid data bytes, which is the number of bytes managed by this table. Word 3 is the total number of bytes in the block and contains the total number of bytes in the block managed by this table.

FIG. 18 shows the contents of VIT in the previously proposed data recorder, FIG. 19 shows the contents of LIDT, and FIG. 20 shows the contents of FIT. Word 0 of the LIDT is the logical ID address, word 1 is the physical ID
Address, word 2 is the file number, word 3 is the absolute block number. Word 0 of the FIT is the physical ID address and word 1 is the absolute block number.

In the data recorder proposed above,
In order to obtain the logical information of the data already recorded on the tape in advance of writing, 10-I from the writing start point
It is necessary to read the data on the tape in the range up to D (I to II in FIG. 14C). As a result, there is a drawback that the writing speed is reduced and the tape is damaged because the tape is read each time writing is performed.

Therefore, according to the present invention, in order to improve the writing speed and reduce the tape damage, the header information (more specifically, the VIT data area) is already written as described below. It is designed so that the logical information of the last data of the data being written is written. According to the present invention, the header information can be read in advance by the loading process when the tape is loaded and held in the memory. Even if the tape is not read at the time of writing, the data to be newly written is already written to the tape. It is possible to add logical information that is continuous with the written data.

FIG. 21 shows the contents of the DIT subcode area according to an embodiment of the present invention. The file number (word 2), LIDT available flag (word 16), and block operation type (word 17) in FIG. 16 described above are excluded.

FIG. 22 shows the contents of the block management table added in the embodiment of the present invention. Compared with FIG. 17 described above, the number of 4-word units is increased to the unit of 8 words. Of these eight words, four words, words 3 to 6, have the same contents as words 0 to 3 in FIG. Word 0, word 1 and word 2 have been added. Word 0 is an ID indicating the attribute of the data block. This ID has the following definition. User block: 0000FFFFh Tape mark block: 0000FF00h Others: 00000000h In this way, by adding the block management table including the attribute of the block, the capacity of 1-ID is required to attach the tape mark TM to 32. Can be reduced to bytes.

Word 1 is the file number of the data block. The file number indicates the file number including the data block. Word 2 is the block number of the data block. This indicates a sequential block number in the file, which is 0 at the beginning of the file.

FIG. 23 shows a logical format of the DIT area according to the embodiment of the present invention. Compared to the previously proposed DIT area logical format described above, in this embodiment, the LIDT and FIT are the CPT.
It has been changed to (Continue Position Table). CPT
The area is 2-ID to 22- with a logical ID and a physical ID.
It is an ID.

FIG. 24 shows the contents of VIT in this embodiment. Compared to the contents of FIG. 18 above, word 4
The difference is that the file number of the last data block is written as 7, and the block number of the last data block is written as word 48. The DIT is moved from the memory onto the tape during the unload process of removing the tape.
Thus, the logical information of the last data already recorded on the tape is written in VIT.

The contents of the CPT are shown in FIG. CP
T is a management table of a writing start point (that is, a break of a recording unit). 8 words of 0 to 7 words correspond to the recording unit. Word 0 therein is the physical ID of the writing start point (denoted as point C). Word 1 is the logical ID at point C. Word 2 indicates the number of IDs managed in this table. Word 3 is the file number at point C. Word 4 is the block number at point C. Word 5 is the absolute block number at point C.

As described above, by providing the CPT and managing all the write start points by the CPT, it is necessary to retrieve the previous write start point between 10-ID before the write start point and the write start point. This eliminates the need to perform the read processing before writing, and can speed up the processing.

The write operation of the embodiment of the present invention will be described. SPACE EO from host computer
SCS the D (move the written data to the end) request
When the I controller 75 receives the data, the main CPU 61 recognizes the data regarding the EOD from the data in the RAM 71. The RAM 71 is loaded with VSIT and DIT (including VIT, CPT, etc.) at the time of loading.

A write command (writing user data) is issued from the host computer. As a preparation, pre-roll to the EOD position. Furthermore, the data from the host computer is transferred to the SCSI controller 75.
Sticks to the bank memory 80. In addition, the main CP
U61 sets block management table to bank memory 80
Create one. As a process, data is secured in the bank memory 80 and a subcode and user data management table is created. FIG. 26A shows 1 in the bank memory 80.
-It is an image of ID.

Next, from the host computer, write FM
A command is issued, and the SCSI controller 75
Is received, T is added to the block management table created above.
The main CPU adds M blocks. That is, FIG.
As shown in FIG. 6B, a TM block is created in the next block management table in the same area (ID) as in FIG. 26A.

The image shown in FIG. 26B is prepared for writing on the tape. In FIG. 26C, I is set to 10-ID from the writing start point. The position of II is the writing start point. As shown in FIG. 24 described above, the VIT in this embodiment has all the logical information (physical ID, file number, block number, etc.) relating to the last data already written on the tape written therein. In addition, all VIT data is stored in the memory (RAM7 at the time of tape loading).
1) Since the data is held on the tape, there is no need to read the previous ID from the write start position on the tape, unlike the previously proposed data recorder.

In this embodiment, the FI is set in the VIT.
It has CPT instead of T and LIDT, and CPT is
It is a table that holds all write start positions. Therefore, the write start position information can be obtained from the RAM 71 without reading the previous write start position from the tape. Therefore, the process of reading the previous 10-ID from the starting point as a preparation, which is required in the previously proposed data recorder, before starting the writing can be omitted.

FIG. 27 is a flow chart of the writing process of the embodiment of the present invention. In step S11,
The logical ID, the file number, and the last block number of the already written data are acquired from the logical information about the last data held in the RAM 71 of FIG. next,
A logical ID, a file number, and a block number are added to the data in the memory 80 while maintaining continuity with the acquired logical information (step S12).

At step S13, the tape position I
~ II is checked to see if it has the previous write start point. This is done by searching the CPT stored in the RAM 71. If there is no writing start point,
Writing is started from II (step S14). Young
If there is a writing start point, 10-
Writing is started from a place separated from the ID (step S1)
5). When writing is started, position II is changed to C in RAM71.
It is reflected in PT (step S16), and the process is ended.

By providing the CPT, it is possible to utilize the CPT to speed up the read operation. That is, the CPT managing the location closest to the file number and block number designated by the host computer is searched in the memory (RAM 71), and further moved to the physical ID managed by the CPT, and its position Read from. By doing so, a considerable speedup can be achieved as compared with searching for the target position from the beginning of the tape.

The present invention can be applied not only to a rotary head type data recorder but also to a data recorder for sequential access.

Further, the data format for writing the logical information about the last recorded data is not limited to the above-mentioned embodiment, and various formats are possible.

[0087]

According to the present invention, since the logical information of the last one of the data already recorded on the tape is written in the header information and this logical information is read when the tape is loaded and held in the memory, the writing process is performed. It becomes unnecessary to read the logical information from the tape prior to. Therefore, the speeding up of the writing operation can be achieved, and the damage given to the tape can be reduced.

[Brief description of drawings]

FIG. 1 is a schematic front view of a data recorder to which the present invention can be applied.

FIG. 2 is a schematic rear view of a data recorder to which the present invention can be applied.

FIG. 3 is a schematic diagram showing a usage example of a data recorder to which the present invention can be applied.

FIG. 4 is a schematic diagram showing a head arrangement of a data recorder to which the present invention can be applied.

FIG. 5 is a schematic diagram showing a track pattern of a data recorder to which the present invention can be applied.

FIG. 6 is a block diagram showing a system configuration of a data recorder to which the present invention can be applied.

FIG. 7 is a schematic diagram showing a tape format of a data recorder to which the present invention can be applied.

FIG. 8 is a VSI of a data recorder to which the present invention can be applied.
It is an approximate line figure showing the format of T and DIT.

FIG. 9 is a BST of a data recorder to which the present invention can be applied.
It is a schematic diagram for explaining.

FIG. 10 is a schematic diagram for explaining a logical format of a data recorder to which the present invention can be applied.

FIG. 11 is a schematic diagram for explaining the format structure of a data recorder to which the present invention can be applied.

FIG. 12 is a more detailed block diagram of a system configuration of a data recorder to which the present invention can be applied.

FIG. 13 is a schematic diagram for explaining a writing process of a data recorder to which the present invention can be applied.

FIG. 14 is a schematic diagram for explaining a writing process of a data recorder to which the present invention can be applied.

FIG. 15 is a flowchart for explaining a writing process of a data recorder to which the present invention can be applied.

FIG. 16 is a schematic diagram showing the contents of a subcode area of a data recorder to which the present invention can be applied.

FIG. 17 is a schematic diagram showing the contents of a block management table of a data recorder to which the present invention can be applied.

FIG. 18 is a VI of a data recorder to which the present invention can be applied.
It is a schematic diagram which shows the content of T.

FIG. 19 is a LI of a data recorder to which the present invention can be applied.
It is a schematic diagram which shows the content of DT.

FIG. 20 is a FI of a data recorder to which the present invention can be applied.
It is a schematic diagram which shows the content of T.

FIG. 21 is a schematic diagram showing the contents of a sub code area according to an embodiment of the present invention.

FIG. 22 is a schematic diagram showing the contents of a block management table according to an embodiment of the present invention.

FIG. 23 is a schematic diagram showing a format of DIT according to an embodiment of the present invention.

FIG. 24 is a schematic diagram showing the contents of VIT according to an embodiment of the present invention.

FIG. 25 is a schematic diagram showing the contents of CPT according to an embodiment of the present invention.

FIG. 26 is a schematic diagram for explaining the writing process of the embodiment of the present invention.

FIG. 27 is a flow chart for explaining the writing process of the embodiment of the present invention.

[Explanation of symbols]

 1 tape drive controller 2 digital information recorder 20 host computer 27 track on which time code is recorded 61 main CPU 70 2-port RAM 71 RAM 75 SCSI controller 80 bank memory 81 sub CPU

Claims (2)

[Claims] 1. A data recorder in which digital data is sequentially written on a tape-shaped recording medium, having logical information of the last data among the data already recorded on the tape-shaped recording medium as header information. When the tape-shaped recording medium is mounted, the header information is acquired and retained, and when new data is written, logical information is added to the new data based on the logical information in the retained header information. A data recorder which is added so as to write the new data and the added logical information. 2. The data recorder according to claim 1, wherein the header information is data for managing a volume, and the logical information includes the file number of the last data block and the block number of the last data block. A data recorder characterized in that.