JPH0441430B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for updating data on a magnetic tape suitable for use in updating teaching data of industrial robots.

[Conventional technology]

The teaching data of industrial robots is generally recorded and stored on magnetic disks or magnetic tapes.
These data must be updated when the workpiece is changed or an error in the teaching data is discovered.

FIG. 2 is a conceptual diagram for explaining a conventional method for updating data D2 among data D1, D2, and D3 recorded in blocks on the cassette tape 1. As shown in FIG.

In this case, first, after confirming the start position A of data D2, move back the time t _{by 1} second and stop at point B.
Turn on the write signal and start erasing data. Then, after advancing for a time t _{by 1} second, the data is updated by writing update data D2a from point C.

[Problem that the invention seeks to solve]

However, the conventional method described above has the following problems.

If you move the tape backwards and then move it forward again, points A and C will not shift due to mechanical constraints, and if you rewrite the information several times, the necessary
IBG (Inter Block Gap) cannot be secured.

Even when the updated data (D2a) is longer than the original data (D ₂ in the above example), a case may occur in which the IBG cannot be secured. In some cases, there is a possibility that even the next data (D3) may be destroyed.

The present invention seeks to solve these problems.

[Means for solving problems]

In order to solve the above-mentioned problems, the present invention provides that when update data is generated, it is assigned a number that is the same as or related to the original data to be updated, and is sequentially written to the magnetic tape (i.e., the data that is currently being written is (later), and when reading data, read the data with the same or related numbers as the desired data in order from the beginning, and make the latest among these data (i.e., the one written last) valid. It is characterized by

[Effect]

According to the above method, updated data is sequentially written to new storage areas on the magnetic tape.
No IBG or data destruction occurs. Additionally, there are no restrictions on data length or number of rewrites, allowing for free updates.

〔Example〕

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a conceptual diagram for explaining one embodiment of the present invention. In this figure, data d ₁ to d ₈ are written in blocks on the cassette tape 11, and an EOF (End of File) is written after data d ₈ .
Mark 12 is written on it. And data
d ₂ , d ₄ , d ₈ are the data of data number No. 1, and the data
d ₈ is the latest one, data d ₃ , d ₅ , d ₇ are data number No. 2 data, data d ₇ is the latest one,
Data d ₁ and d ₆ are data with data number No. 3, and data d ₆ is the latest data.

Reference numeral 13 is a cassette tape data reading area provided on the main storage device, in which data di (i=1,
2...) are stored in this area 13. In this case, the read data di is sequentially overwritten in the area 13, so that only the latest data remains in the area 13.

In such a configuration, writing of the latest data (hereinafter referred to as original data), writing of updated data, and reading of data are performed as follows.

(1) Writing original data.

Each data is assigned a data number and written to the cassette tape 11 in blocks.

An EOF mark 12 is written at the end of the write data.

(2) Writing update data.

When updated data is generated, it is given the same (or related) data number as the original data to be updated.

Next, the cassette tape 11 is advanced and the EOF mark 12 at the end is searched for.

When the EOF mark 12 is found, it is erased and overwritten with updated data, and then a new EOF mark 12 is written. In this way, the original data remains as is, and the updated data is sequentially written to new areas of the cassette tape 11.

(3) Reading data.

As an example, reading of data with data number No. 1 in FIG. 1 will be described.

After rewinding the cassette tape 11, it is moved forward, and each time data with data number No. 1 is found, it is read into the area 13. As a result, data d ₂ , d ₄ , and d ₈ are sequentially overwritten in area 13, and when reading up to EOF mark 12 is finished, data d ₈ remains as the latest data.

The data _d8 is assumed to be valid data.

In this way, desired data can be read into the area 13.

Although the above method requires a longer read time and a larger storage capacity than the conventional method, the frequency of reading the teaching data is very low (for example, once a day).
(times), the update frequency is even less, and the capacity of the cassette tape is extremely large, so there is no problem in practical use.

〔Effect of the invention〕

As explained above, in this invention, when update data is generated, it is sequentially written to a new area of the magnetic tape, so updates can be freely performed without being restricted by the length of the update data or the number of updates. Benefits can be obtained.

[Brief explanation of drawings]

FIG. 1 is a conceptual diagram for explaining an embodiment of the present invention, and FIG. 2 is a conceptual diagram for explaining a conventional data updating method. 1, 11...Cassette tape (magnetic tape).

Claims (1)

[Claims] 1. In a magnetic tape data update method that updates data written on a magnetic tape in blocks, when updated data is generated, it is written on the magnetic tape with a number that is the same as or related to the original data to be updated. While writing sequentially, when reading data, sequentially reading data having the same or related number as desired data,
A magnetic tape data update method characterized by validating the latest data among these data.