Error detection/correction and fault detection/recovery – Pulse or data error handling – Digital logic testing
Reexamination Certificate
2000-03-25
2003-09-30
Chung, Phung M. (Department: 2133)
Error detection/correction and fault detection/recovery
Pulse or data error handling
Digital logic testing
C714S710000
Reexamination Certificate
active
06629278
ABSTRACT:
TECHNICAL FIELD
The present invention relates to a technique of compressed data restoration processing for restoring the compressed data such as the test pattern data which were transferred to a semiconductor tester in succession and at a high speed.
BACKGROUND ART
It has widely been made that data is temporarily compressed for the purpose of the data transfer and the like, and thereafter the thus compressed data is restored (decompressed). Restoration processors (typically compression/restoration processors) have been in common use for such restorations of the compressed data.
Referring herein to
FIG. 8
, a conventional example of a technique for restoring the compressed data will be described for the better understanding of the present invention.
FIG. 8
is a block diagram for explaining a method for conventional compressed data restoration.
In cases where a compressed data row
280
is restored by a restoration processor
16
to generate a restored data row
340
, it is commonly necessary to input restoration processor control data
84
into the restoration processor
16
. Such restoration processor control data
84
includes, for example the size (bit number) of the compressed data row (sometimes called “a quantity of the compressed data row”) and the size (bit number) of the pre-compression source data row (sometimes called “a quantity of the pre-compression source data row”). Also, the data input (hereinafter sometimes called “programming”) is carried out by using a control software
82
which operates on a control processor
80
.
Then, when the compressed data row
280
is fed to the restoration processor
16
into which the restoration processor control data
84
has been programmed, the restored data row
340
is generated. After the completion of the restoration processing of the compressed data row
280
, the restoration processor
16
provides a restoration termination notice
86
to the control processor
80
. In response to this restoration termination notice
86
, the control software
82
starts the programming for allowing the restoration processor
16
to perform restoration processing of the next compressed data row.
Here, the reason will be described that the control software is troublesomely required each time the control data is programmed into the restoration processor.
In sequential writing of compressed data rows into the transferee storage device, none of control data has been acquired at the stage of the compression processing. Furthermore, in order to restore the compression data rows by means of the restoration processor, there is a need for control data to be programmed into the restoration processor prior to the entry of the compressed data rows. As a result of this, upon restoration of a compressed data row, it is necessary to separately perform the operation to retrieve control data corresponding to the compressed data row and to enter and program the thus retrieved control data into the restoration processor. For this reason, the control software is needed for execution of the retrieval or other processing.
As described above, in the conventional compressed data row restoration, the restoration processor control data must be individually programmed by means of the control software on a compressed data row basis. This means that, accordingly, as the number of the compressed data rows becomes larger, the number of operating times of the control software will also increase. Also, the operation of the control software needs a certain time for the programming, and correspondingly the restoration processing speed will become lower. This resulted in a deficiency that too much time is required for the restoration processing in the case for restoring a large number of compressed data rows in succession.
A plurality of the compressed data rows to be restored in succession in this manner include, typically, test pattern data for use in a semiconductor tester. In this case that the test pattern data, which is dedicated to semiconductor integrated circuits and which is used for testing, is transferred as compressed data to the semiconductor tester, the semiconductor tester carries out the semiconductor testing with use of the test pattern data restored through the restoration processing.
However, in the case of using an enormous quantity of test pattern data, the time taken for the restoration of the compressed data may possibly become much longer than the time needed for the semiconductor testing. In addition, the semiconductor testers can not test the integrated circuits during the restoration processing. Thus, for effective utilization of the costly semiconductor tester, it has been desired to reduce the time required for the restoration processing through its speed-up.
The present invention was conceived with the aim of solving the above problems. It is therefore an object of the present invention to provide a method and apparatus to restore the plural compressed data rows in succession at a high speed for reducing the time taken for the restoration.
SUMMARY OF THE INVENTION
In order to achieve the above object, according to the present invention, there is provided a compressed data restoration apparatus, which is designed to restore the plural compressed data rows obtained by a compression process for the plural source data rows, to generate the plural restored data rows.
Namely, the present invention provides a compressed data restoration apparatus, which comprises;
a first storage unit for storing therein a main file composed of the plural unit files each including a compressed data row and control data required for restoration thereof, each unit file provided for each compressed data row, the main file containing the dummy data in place of the dynamic control data to be acquired after generation of the compressed data rows;
a second storage unit for storing therein a sub-file containing the dynamic control data acquired from the control data for the compressed data rows after generation of the compressed data rows;
a substituted control data generation unit which upon the generation of restored data rows by restoration of the compressed data rows, reads out the unit files from the first storage unit and the dynamic control data from the second storage unit so as to substitute the dummy data of the control data with the dynamic control data in the sub-file for each of the unit files to thereby generate the substituted control data;
and a restoration processor which accepts the compressed data row and the substituted control data from the control data generation unit for each of the unit files so as to restore the compressed data rows by use of the substituted control data to thereby generate restored data rows.
In this manner, according to the compressed data restoration apparatus of the present invention, the main file contains in advance the plural unit files each containing a compressed data row and control data therefor in pairs so that the compressed data rows are restored on a unit file basis. To this end, upon the restoration of the compressed data rows, the compressed data rows are correlated in advance with the control data therefor. As a result, without taking the trouble to retrieve control data corresponding to the compressed data rows by use of the control software in the prior art, the corresponding control data can be programmed to the restoration processor.
Incidentally, the control data includes the dynamic control data to be acquired after generation of the compressed data. This dynamic control data is unknown at the stage of creating the unit files in the main file. In the present invention, for this reason, each unit file stores the dummy data in place of the dynamic control data, whereas the sub-file is created which holds each dynamic control data corresponding to each compressed data row. Then, upon restoration of the compressed data, the dummy data is substituted with the dynamic control data to generate the substituted control data.
Accordingly, according to the present invention, the compressed::data can be restored by p
Advantest Corp.
Chung Phung M.
Muramatsu & Associates
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