JPH0318206B2 - - Google Patents

Description

Detailed Description of the Invention (a) Technical Field of the Invention The present invention records a tape mark identification number for each tape mark stored in order to divide a recording medium into data file units, and also distinguishes between tape marks and tape marks. The present invention relates to a recording apparatus that records a data block identification number for each data block recorded during the recording process, and particularly to a block management method of the recording apparatus when writing a new data block in a predetermined file.

(b) Technical Background Various methods have been developed and implemented for recording/reproducing data on recording media. The importance of data recorded on/reproduced from a recording medium is increasing as the usage of data processing devices becomes more sophisticated and complicated. Under these circumstances, there is a need for more advanced and reliable management methods for recording/reproducing data on recording media.

(c) Prior Art and Problems The block management method of a conventional recording device will be explained using a magnetic tape as an example.

FIG. 1 shows an embodiment of a conventional magnetic tape block management method.

In the figure, 1 is a magnetic tape medium, 2 is a tape mark, 3 is a data block, 4 is a data file (), 5 is a data file (), and a to d are magnetic heads (not shown). Indicates relative position to the magnetic tape.

The data block 3 is given data block management information consisting of a data block identification number and a tape mark identification number.

Furthermore, when data block 3 is added to data file () 4, data file () after point c is overwritten and erased. Therefore, it is usually copied onto a separate medium.

Now, the magnetic head (not shown) is positioned at point a, and if you want to add data in this state, send a forward space command (move the magnetic tape medium 1 in the forward direction) from the host device (not shown). When detecting advance tape mark 2, a stop operation is issued. After executing the forward space command, the position of the magnetic head (not shown) moves to point d. At this time, in the magnetic tape control device (not shown), the tape mark identification number (TSN) of the data file ( ) 5, ie, the number n+1, is recognized as the tape mark identification number (TSN). However, the data block identification numbers (BSN1, BSN2,...) are not recognized.

Next, the magnetic tape controller (not shown) issues a backward space command (advances the magnetic tape medium 1 in the backward direction and detects tape mark 2 or data block 3) in order to move to the data file () 4 position to be added. Then, the magnetic head (not shown)
Move the position of to point c. At this time, the tape mark identification number (TSN) is minus 1 and becomes n, but the data block identification number (BSN1,
BSN2…) is not recognized.

Next, when a write command is issued from the host device (not shown), the magnetic tape control device (not shown) writes the data block 3 to be added.
Data block identification number (BSN1, BSN2…)
In order to confirm the data block and to ensure a sufficient gap between data blocks, a backspace block (operation in which magnetic tape medium 1 advances in the backward direction and stops when data block 3 is detected) is executed. do. This allows the position of the magnetic head (not shown) to be
Go to the location and enter the data block identification number (BSN1,
BSN2…). Now move on to the write operation, advance the magnetic head in the forward direction with a sufficient constant gap from the last data block just read, and read and confirm the data block identification number in data block 3 just before writing. (BSNn) plus 1, that is, BSNn
+1 is written as the first data block identification number to be added. However, if the distance to the immediately preceding data block 3 (identification number BSNn) is sufficiently longer than the predetermined length (if there is an unrecorded portion because information cannot be recorded due to a defect on the magnetic tape medium 1, etc.) Backspace block (operation in which magnetic tape medium 1 is advanced in the backward direction and stopped when data block 3 is detected)
is executed multiple times, the previous data block 3
First data block 3 (identification number BSNn +
There is a disadvantage that the time loss required for positioning 1) becomes large.

(d) Purpose of the Invention The purpose of the present invention is to provide a novel block management method for a recording device that eliminates the above-mentioned drawbacks.
In particular, when adding to a data block, this record eliminates the time loss required for positioning to the previous data block and to the first data block to be added, making it possible to efficiently add to the data block. The object of the present invention is to realize a block management method for devices.

(e) Structure of the invention A tape mark identification number is recorded for each tape mark recorded to divide a recording medium into data file units, and a data block is recorded for each data block recorded between tape marks. In a recording device that records an identification number,
When the data block is additionally recorded in the data file, information indicating that the previous data block was not found and the data block identification number are renumbered from the initial value and are additionally recorded.

(f) Examples of the invention The present invention will be explained below with reference to the drawings.

FIG. 2 shows an embodiment of a magnetic tape control device according to the present invention, and FIG. 3 shows an embodiment of a data format on a magnetic tape medium according to the present invention.

In this embodiment, the recording method on the magnetic tape medium is a configuration called 18 tracks in which 18 bits are simultaneously recorded in the width direction of the magnetic tape medium.

In Figure 2, 6 is an interface circuit, 7
is a multiplexer circuit, 8 is a buffer circuit, 9 is a modulation/write circuit, 10 is a demodulation/read circuit, 1
1 is the serial number sampling circuit (hereinafter
12 is a serial number generation circuit (hereinafter referred to as SN generation circuit), 13 is a serial number register circuit (hereinafter referred to as SNR circuit), and 14 is a microprocessor (hereinafter referred to as MPU).
), 15 is a magnetic tape control device, 16
is a shared register circuit, 17 is a magnetic tape device, 1
8 is A zone, 19 is B zone, 20 is data group (), 21 is data group (), 22
23 indicates a residential data group, and 23 indicates a CRC data group.

In addition, in Fig. 3, D1 to D17 are write data, ECC is an error correction code, Pd is padding data, and tape mark identification numbers (TSN1,
TSN2,...), , indicate data block identification numbers (BSN1, BSN2,...), and control flags, respectively.

The magnetic tape control device 15 in FIG. 2 receives input data from an interface circuit 6 that exchanges information with a host device (not shown), the interface circuit 6, a demodulation/read circuit 10, and a serial number generation circuit 12. Select buffer circuit 8
A multiplexer circuit 7 outputs the input data to the multiplexer circuit 7, a buffer circuit 8 temporarily stores the input data from the multiplexer circuit 7 and sequentially outputs it to the modulation/write circuit 9, modulates the input data from the buffer circuit 8 and writes it to the magnetic tape as write data. Modulation/write circuit 9 and magnetic tape device 17 for transferring data to device 17
The demodulation/read circuit 10 converts the read data from the data block into demodulated read data.
BSN2,…) and tape mark identification number (TSN1,…)
TSN2,...) and SNS for extracting control flags
The circuit 11 creates data block identification numbers (BSN1, BSN2, ...), tape mark identification numbers (TSN1, TSN2, ...) and control flags to be added to the data block 3 to be added, and sends them to the multiplexer circuit. Output to 7
It controls various controls in the SN generation circuit 12, the SNR circuit 13 located in the MPU 14 and storing data block management information, and the magnetic tape control device 15.
It is composed of MPU14.

The magnetic tape device 17 has a shared register 16 for storing data block management information.

Next, the data format on the magnetic tape medium shown in Fig. 3 is divided into A zone 18 and B zone 19, each of which has 9 bits in the vertical direction, and 4 pieces of data each consisting of 8 bytes arranged in each zone. It is composed of groups 20, 21, 22, and 23.

In this embodiment, the write data transferred from the host device (not shown) is 17 bytes.

First, the odd-numbered byte write data is distributed to the A zone 18 side, and the even-numbered byte write data is distributed to the B zone 19 side.Furthermore, each distributed write data is divided into 7-byte write data data groups for each zone. ()20, ()
Separate into 21 parts. Since an error correction code (ECC) which is check data for error correction is added to each data group 20-23, each data group 20-23 is formed of 8 bytes. Note that if the data allocated to the data group ( ) 21 is less than 7 bytes, padding data Pd is added for the missing bytes.

Data group ()2 consisting of data transferred from a higher-level device (not shown)
0, () 21, both A zone 18 and B zone 19 are further residential data group 22,
A CRC data group 23 is added. Data according to the present invention is recorded in the first to fourth bytes of the residential data group 22.

1st byte is tape mark identification number, 2, 3
The data block identification number is recorded in the first byte, and a control flag is recorded in the fourth byte. Above 4
The same byte data is written in both the A zone 18 and the B zone 19, and when data is read, the data on the A zone 18 side and the data on the B zone 19 side are compared. Also Residential Data Group 22
In the fifth and subsequent bytes and in the CRC data group 23, check bits (CRC) and other information for all data transferred from a host device (not shown) are recorded.

Next, the operation when adding data block 3 to the data file (corresponding to the data block 3 identification number BSNn and later) will be explained.

Assume that a magnetic head (not shown) is positioned at point a. When a forward space command (operation of advancing the magnetic tape medium 1 in the forward direction and stopping when tape mark 2 is detected) is issued from a higher position (not shown) at point a, the MPU 14 uses the internal SNR circuit 13 to Add 1 to the currently recognized tape mark identification number (TSNn) and set the data block identification number to zero. Then, transfer the contents to the magnetic tape device 1.
7 and instructs the magnetic tape device 17 to perform a forward space command operation. The magnetic tape device 17 moves the magnetic tape and stops at point d where a magnetic head (not shown) detects the first tape mark.
Further, a backward space command (an operation of advancing the magnetic tape medium 1 in the backward direction and stopping when tape mark 2 or data block 3 is detected) is issued from a host device (not shown). With this command, the MPU 14 retrieves the data block management information stored in the shared register 16 in the magnetic tape device 17 to the SNR circuit 13, and
A backward space command operation is instructed to the magnetic tape device 17, and the magnetic tape device 17 positions a magnetic head (not shown) at point c. At this time, when the MPU 14 recognizes that the data read by the backward space command operation is tape mark 2, it subtracts 1 from the tape mark identification number (TSNn+1) in the SNR circuit 13, and
The data block identification number is set to zero, and the U flag (not shown) in the control flags to be stored in the 4th byte of the residential data group 22 (called the undefined flag, which is normally reset to "0") is set. , is set to "1" when tape mark 2 is detected by a back read command, and is reset to "0" when data block 3 is detected. A W flag not shown (referred to as a write flag; when "1" indicates that a write-related command was executed immediately before) is set to "0" and stored in the shared register 16. At this point MPU
14, the tape mark identification number "TSNn" is recognized, but the data block identification number is not recognized.

At this point, a write command is issued from a host device (not shown). This command
The MPU 14 reads the data block management information from the shared register 16 into the SNR circuit 13, and since the W flag (not shown) in the control flags is "0" and the U flag is "1", the MPU 14 reads data block management information from the shared register 16 into the SNR circuit 13. It recognizes that tape mark 2 has been read, and performs a backspace block (an operation in which the magnetic tape medium 1 advances in the backward direction and stops when data block 3 is detected) prior to the write operation to position the tape at the correct position. Then, in order to recognize the data block identification number to be written, the previous data block 3 is
(The data block identification number BSNn is recorded).

When I go to read the immediately preceding data block 3 (in which the data block identification number BSNn is recorded), the distance to the immediately preceding data block 3 (in which the data block identification number BSNn is recorded) is less than the predetermined length. If it is long enough, it is an area where there is no data block because there is an unrecorded part because it has been erased (erased) or because information cannot be recorded due to a defect on the magnetic tape medium 1, etc. , the MPU 14 determines. Therefore, if the MPU 14 interrupts the operation of reading the immediately preceding data block 3 and moves on to the write operation, when writing the data block management information to the SN generation circuit 12, if the immediately preceding data block identification number cannot be recognized and Therefore, the data block identification number is set to the initial value "0" and the control flag (not shown) is set to "1" to indicate that data block 3 was not found, and additional data can be added. first data block 3
For subsequent writing of data block 3, the U flag is set to "0", and the data block identification numbers are assigned sequentially as 1, 2, and so on.

Next, when reading data blocks 3 written in the above sequence sequentially, even if the data block identification number and sequence read just before are corrupted,
When the U flag is "1", it is recognized as additional data, and even if the data block identification number starts from "0", the expected data block 3
The MPU 14 determines that the data has been read and processes it normally.

That is, in the past, the immediately preceding data block was always read to recognize the data block identification number, and in order to read the immediately preceding data block, the backspace block operation was performed multiple times until the data block was found. Although time is wasted for the operation, when data blocks are added according to the present invention, the backspace block operation is performed only once, which speeds up the processing time.

(g) Effects of the invention When adding to a data block according to the present invention as described above, there is a time loss required for positioning up to the immediately preceding data block and positioning it on the first recording medium to be added. The present invention has the advantage that it is possible to provide a block management method for a recording device that enables efficient addition of data blocks.

[Brief explanation of the drawing]

FIG. 1 is an embodiment of a conventional magnetic tape block management method, FIG. 2 is an embodiment of a magnetic tape control device according to the present invention, and FIG. 3 is an implementation of a data format on a magnetic tape medium according to the present invention. An example is given for each. In the figure, 1 is a magnetic tape medium, 2 is a tape mark, 3 is a data block, 4 is a data file (), 5 is a data file (), 6 is an interface circuit, 7 is a multiplexer circuit, 8 is a buffer circuit, 9 10 is a modulation/write circuit, 10 is a demodulation/read circuit, 11 is an SNS circuit, 12 is an SN generation circuit, 13 is an SNR circuit, 14 is an MPU, 15 is a magnetic tape control device, 16 is a shared register circuit,
17 is a magnetic tape device, 18 is an A zone, 19 is a B zone, 20 is a data group (), 21 is a data group (), 22 is a residential data group, and 23 is a CRC data group.

Claims (1)

[Claims] 1 Record a tape mark identification number for each tape mark recorded to divide the recording medium into data file units, and record a data block identification number for each data block recorded between tape marks. In the recording device, when the data block is additionally recorded in the data file, information indicating that the previous data block was not found and the data block identification number renumbered from the initial value are added and recorded. Features: Block management method for recording devices.