JPS5873009A - Magnetic tape controlling system - Google Patents

Abstract

PURPOSE:To reduce the write processing speed, by writing a data having an error detected at the reading check during write into a data block and avoiding a magnetic tape from being wound. CONSTITUTION:If data are not normally written on a magnetic tape 1, an error mark EM is written after the data, this data block B is taken as an error block and the figure of a block number buffer 10 is not revised. After a gap is formed, the same block number and data to be written in the block B are written in the next data block B' again. After the block B' is written, a gap GAP is similarly witten, the block number is revised, the next write data is written from a host 13 and fetched to a data buffer 11, and the next block number and data are written in a data block C.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a read-after-write operation (rea(i aft
θrwrj-te) The present invention relates to a magnetic tape control system in an apparatus performed in 1.

Conventionally, magnetic tape devices are equipped with a read head after a write head, and when writing data, the data is read immediately after writing, and it is possible to check whether the data has been correctly written to the magnetic tape. I checked it. That's it
C1: If an error is detected in this check, the magnetic tape is rewound to the beginning of the error block and the data is rewritten.

However, with this method, the magnetic tape must be rewound and data must be rewritten every time an error is detected, which increases the write processing time (not only "L, T" but also There have been various problems such as the unwinding operation destroying the normal data block before the error block, or failing to erase the error block that should have been erased.Furthermore, the read check during the write operation has caused various problems. Even if an error mark is written in a data block where an error has been detected, there is a risk that the error mark will be misjudged during the reading operation, resulting in block omissions or block additions. cormorant.

In view of this point ζ, the present invention is based on the fact that the magnetic tape is not rewound at all during the write operation 62.

Data write processing time vm is reduced and data 9-
The present invention provides a new magnetic tape control system that allows error blocks to be reliably determined during a read operation by writing not only an error mark but also a block number in the j-lock.

Hereinafter, the present invention will be explained with reference to the drawings.

FIG. 1 is a block diagram showing an embodiment of the magnetic tape control system according to the present invention, in which (1) is a magnetic tape on which a data block D is recorded, (23RL and 13) are a read head and a write head, respectively; (41 is a magnetic tape device, (51 is a processing unit that performs various processes, (6) is a processing unit (
5) control signal R3O based on data from.

an input/output control unit (7) which outputs FBOv and inputs a control signal TMO1BLS from the magnetic tape device (4);
) is a serial/parallel converter that mutually converts parallel data (IkK column data) and serial data into parallel data.

18) is a modulation sub-section that modulates the write data V and demodulates the read data tube, and (9) is an input/output control section (6) or [#1 column conversion section 17] depending on the address from the processing section (5). an address decoder that selects m, on, a
a is a program number buffer, a write data buffer, and a read data buffer, respectively.

Next I: The operation of this embodiment will be explained.

First, in the IF write operation, the write address is applied from the processing section (5) to the address decoder (9), and the input/output control section (8) is selected. The detector is input to the input/output control unit (61) and outputs a signal R8O for instructing tape regular running and a tape running direction switching signal FBO.Then, these signals cause the magnetic tape device +41X' to almost move.I: As a result, the magnetic tape (1) is fixed in the forward direction.

Continuation: [, processing unit f5) sends the address to the address decoder (91 ('?,) to select serial/parallel replacement unit (7)
Take in data from the block number buffer αG and write data buffer nD, and connect to the data bus! [Parallel converter (7) sets the input parallel data! Included data WDT
By adding the block number and data to the magnetic tape device (4), the block number and data are written to the magnetic tape device (4) as shown in Figure 182.

Here, as shown in Fig. 2 (a), one block buffer buffer constitutes a so-called register, and is used as a block buffer.
...... and use it in order of increasing prerequisite value.

Also, the write data buffer lIl is 112 Figure: 4C:
As shown in the figure, it stores data for % 1 block), and these data are data 1 to data nl.
The magnetic tape (1) (=, data is written to the magnetic tape (1) as shown in FIG. 1-
The lower 2 of the addition data from to data n is written as checksum data after data n.

By the way, when the digital data is written, the written data is read by the read-after-write 1 set by the read head (2) and sent to the magnetic tape device (4).
The read data RDT is added to the demodulator (8). Then, the demodulated read data alI & column converter (7) converts the serial data to parallel data C. At this time, [!1 column conversion Since the section (7) gives the processing section (5) 1: interrupt signal RQv, the processing section (5) gives the address to be selected by the serial/parallel substitution section (7) v to the address decoder 19), and therefore reads the read data. is the processing unit (5)l
The read data l(ttS+=) is stored as shown in FIG. 2(c).

Therefore, the processing unit (5) adds the read data number (dark 1 to data n4 of rough y6m) and compares the lower 2 bytes of the added dark with the read checksum data. When there is a match,
Figure 3) i = C nib tab block (F) & I as shown
When m1m gear AP 'll' is written, the value of the block knife bar buffer tte is 'P+IL% host)+
From t:1, the next write data is taken in and the next data block is written on the magnetic tape (1) (:) in the same operation as described above.

If the tocoguchi cannot find a match with the checksum data, it determines that the data could not be written normally for some reason, and writes the data after the data as shown in data block B in Figure 5 (a).薯：Error mark PM% e.g. r
FFJk Write several bytes, set the data block BY error block, and write the block number buffer ■ value vI
! After the gap 't' is collected, the same block number and the same data to be written in the error block B are written again in the next data block B. However, when writing the same Mv as Eranimark, the read-after-write check is not performed, and after writing the data block Bt-, the gap GAPv is written and the block number is updated as described above.

The next write data is taken from host) 03 into the write data buffer aυ, and the next block number and data are written into data block C.

In this manner, during writing, data is written one after another without rewinding the magnetic tape to rewrite data blocks.

Next, the reading operation will be explained.

Even in the read operation, as in the write operation, first, the input/output control section (6) is selected by the processing section (5), and the control signals R8C and FBC are applied to the magnetic tape device (4), and the magnetic tape ( 1) is controlled to run in the forward direction. Subsequently, the parallel converter (7) is selected in "C", and the data continued in the read-out mode (2) is input to the modulation/demodulation section (8) via the magnetic tape device (4). After being demodulated here, it is converted into parallel data in a serial/parallel converter (7).Then, the read data is taken into a read data buffer (11) by an interrupt signal IRQ.

Therefore, as in the read-after-write check, the check chip data is compared with the lower two bytes of the data obtained by adding data nv from the read data 1. As a result of the comparison,
If the data match, add 1 to the block number and read the next data block.

However, if the data do not match, error mark confirmation mv is performed. Block signals BI and S are used to confirm this error mark. That is, the block signal BLS
is at the "L" level in the data block, and is at the rFIJ level in the gap GAP, and the error mark IM is at the end of the data block, that is, at the [ of the gap GAP].
There is a C written before. Followed by C1 block signal BL
The error mark can be confirmed by checking the data just before s changes from the "L" level to the rHJ level.

As a result of the confirmation, if there is no error mark, read the data block 1 of Hoko again and it matches the checksum again! Take. That is, from the processing unit (5) to the input/output control unit (61r
: By sending control data.

Output the signal R80v and invert the signal FBO,
The magnetic tape (1) is run in the direction of the pack from a stop position P shown in Fig. 3 (main). Then, the block signal is rTl
, J level to rHJ level [2], a constant count is performed using the signal TMO from the tachometer, and the magnetic tape is stopped at the vQ position as shown in Figure 4. Here, the reason why the signal 〒MOv is used is to stop the magnetic tape t gap GAP at a predetermined position. and,
When the magnetic tape stops, by inverting the signal FBO'lk again, the magnetic tape! Forward direction (run twice and reread to settle down. If the checksum does not match even after repeating the rereading several times or dozens of times, it will be treated as a reading error.
As a result of checking the error mark, if there is an error mark, reread it as described above! read the next data block. That is, since it is determined from the presence of the error mark that this data block has not been written normally, re-reading is not performed and the next data block in which normal data has been written is read.

By the way, since error marks are also read in the same way as normal data, there is a possibility that error marks will be misjudged. That is, referring to FIG. 5A1, it is determined that there is an error mark in the data block A that does not have an error mark, or
However, in the present invention, when t=S, the data block B with an error mark may be determined to have no error mark.
Moreover, since the same block parser is written in the error block and the next data block,
As mentioned above (even if it is determined that data block A has an error mark, the block number of the primary data block B is larger than the block number of data block A, so it is possible that the error mark is incorrectly determined. Also, even if it is determined that there is no error mark in data block B, since the block notifier of the next data block B is the same as that of data block B, it is still a misjudgment of an error mark. As described above, using the block number eliminates the error mark error 1: by using the block number.

As described above, the magnetic tape control method according to the present invention does not rewind the magnetic tape during writing, so that the writing processing time can be shortened.

Rewinding operation: A method that can solve various problems such as destruction of previous data and incomplete erasure of error blocks.
When reading, the error mark and block f/(-
Since it can be determined that the data block is a confirmed error, it is also effective in shortening the reading time.

[Brief explanation of drawings]

Figure 1 shows an embodiment of the magnetic tape control system according to the present invention! Shown T block diagram, Ill! Figures 2 (A1 to (C) are explanatory diagrams showing the contents of various data parameters ÷ 1, Figure 112) is an explanation showing the state of writing data to the magnetic tape, and Figure 5 (A) is an explanatory diagram showing the contents of various data parameters ÷ 1. Fig. 3 is a waveform diagram showing the block signal BLSv. Explanation of main figure numbers '

Claims (1)

[Claims] 1) Add block number 1 to each data block, write the data block on the magnetic tape with a gap between C1, read the data block immediately after writing, and read the data block during the C1 write operation. A magnetic tape control characterized in that when an error mark is made during checking, an error mark is written in the data block, and the same data and the same block number as the data to be written in the data block are written in the next data block. method.