JPH0756785A - Digital signal recording/reproducing memory - Google Patents

Abstract

PURPOSE:To reduce the quantity of processing required for the retrieval of a file allocation table(FAT) and to attain high speed message management by providing a directory(DIR) with a free cluster DIR indicating the position of the leading FAT of a free cluster in a memory area. CONSTITUTION:At the time of recording data, the value of the free cluster DIR is read out and written in a DIR corresponding to a message number to record the value this time. Then, data are written in a cluster corresponding to an FAT corresponding to the value. When the capacity of the cluster being written at present is filled with data, an FAT number corresponding to a cluster in which data are to be written next, is searched. The position of the cluster for writing the succeeding data is found out based upon the number. In the case of ending recording, the number written in the FAT part corresponding to the cluster in which final data are written, is written in the free cluster DIR and an end mark is written in the FAT part.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a digital signal recording / reproducing memory for recording / reproducing encoded data in / from the memory, and more particularly to a memory having a random access function.

[0002]

2. Description of the Related Art In recent years, an audio signal encoding technique for converting an audio signal into a digital signal, further compressing the data to convert it into a smaller amount of data, and then transmitting or recording the audio signal has been put into practical use. For example, an IC recording type answering machine that compresses the message of the other party and stores it in a semiconductor memory corresponds to it.

When a compressed message as described above is stored in a semiconductor memory, information is simply written according to a write address. When writing a plurality of messages in the same memory, what is in the memory where? It is necessary to manage whether or not the data of is written. Therefore,
A method of providing a message management area in the memory and individually managing from which area of the memory the message is recorded for a plurality of messages written in the area can be considered.

FIG. 4 is a block diagram of a conventional digital signal recording / reproducing memory having the above-mentioned configuration.

In FIG. 4, a is a DIR (directory) part, and b is a FAT (File A-locatio).
n Table) part and c are cluster parts.

The operation will be described below. A cluster is a division of memory into a fixed amount of
It is the minimum unit for writing data to memory. FAT
Are provided in the same number as the number of clusters, and the clusters and the FATs have a one-to-one correspondence. The FAT indicates the continuity of the data recorded in the cluster.

Inside the FAT, the FAT number corresponding to the cluster in which the data following the data written in the cluster corresponding to the FAT is written is written. It is possible to continuously reproduce the message data recorded in the clusters in a discontinuous manner.

The DIR has a one-to-one correspondence with the recorded message.
It is provided in the memory so as to correspond to. Therefore,
It is not possible to record more messages than the number of DIRs. Inside the DIR, the FAT number corresponding to the first cluster in which the encoded data of the message corresponding to the DIR is written is written.

FIG. 5 is a flowchart showing a data recording processing procedure in the conventional example. When recording data, first, in step S1, the total number of clusters n is set to n = 0, and in the next step S2, the information in the n-th FAT is read. In the next step S3, it is determined whether the read information is unused information. Here, when it is determined that the information is unused information, the process proceeds to step S4, the information is written in the crystal corresponding to the FAT, and the process proceeds to step S5.

If it is determined in step S3 that the information is not unused information, the process proceeds to step S5, where n = n +
The process of 1 is performed and the process returns to step S2 to read the information in the n = n + 1th FAT.

That is, when recording data, it is necessary to first determine which cluster is a free area. To do this, read the value of each FAT and check if the cluster corresponding to that FAT is unused. If an unused cluster is found in this way, the position of the FAT corresponding to that cluster is written in the DIR corresponding to the message number to be recorded this time. Then, the data is written in the cluster corresponding to the FAT corresponding to the value.

Further, when the capacity of the cluster currently being written is full, the FAT number corresponding to the cluster to which data is to be written next is searched for. The method of searching for this is as described above, and the position of the cluster to which the next data is written is obtained based on the found FAT number. When the recording is completed, the end mark is written in the FAT portion corresponding to the cluster in which the data was last written.

At the time of data reproduction, first, the DIR value (FAT number) corresponding to the message number to be reproduced is read, and the data in the cluster corresponding to that value is read. After reading all the data in the same cluster, the FAT corresponding to the cluster in which the following data is written
Find the number. The number to be searched is written in the FAT corresponding to the cluster from which data has been read so far.
Therefore, the position of the cluster in which the next data is written is obtained based on that number. If the number written in the FAT (fat number corresponding to the cluster in which the continuation of the data is recorded) is the end mark, the writing of the data currently being read is completed there.

When erasing data, first, the DIR value (FAT number 1) corresponding to the message number to be erased is read. Next, the FAT number 2 corresponding to the cluster in which the subsequent data is stored in the FAT is read. After reading the above-mentioned value, a value indicating that the cluster corresponding to the EAT is unused is written in the EAT in which the data was stored. The same processing as described above is performed for the FAT number 2 that was read previously. The above processing is repeated until the read FAT number becomes the end mark indicating the end of the message.

[0015]

However, in the above-mentioned conventional method, it is necessary to search whether or not there is a vacant area for all the maximum FATs at the start of recording and at the end of writing of the currently recorded cluster. However, when high-speed processing such as voice coding frame processing is required, there is a problem that data writing processing cannot be completed in time.

An object of the present invention is to solve the above-mentioned conventional problems, and it is an object of the present invention to reduce the number of processes required for FAT search and to perform message management at high speed.

[0017]

To achieve the above object, the digital signal recording / reproducing memory of the present invention has a message management area in a part of the memory area, and the message management area is at least a memory for each message. The directory area indicating the recording start position in the area and the file allocation table area indicating the continuity information of the clusters or free clusters recorded in the memory area of each message are further divided into at least the memory area. It is configured to have a free cluster directory that points to the position of the first file allocation table of the free cluster in the directory.

[0018]

According to the present invention, when a plurality of data are recorded in the memory by the above-mentioned configuration, when the data is managed by using the directory file allocation table and the cluster, the file allocation table (FAT) search at the time of writing the data is performed. The number of times can be reduced.

[0019]

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

FIG. 1 is a block diagram of a memory in an embodiment of the present invention. A semiconductor memory is used as a recording medium memory for recording / reproducing a digital signal in this embodiment.

In FIG. 1, a is a DIR part and b is a FAT.
Part, c is a cluster part, and d is a free cluster DIR.

The operation of the digital signal recording / reproducing memory configured as described above will be described below with reference to FIGS.

First, it is necessary to perform initialization so that data can be recorded in the memory. FIG. 2 shows the state of the memory at the time of initialization, and the following work is performed at the time of initialization.

Data indicating that the message corresponding to the DIR is not currently written is written in each DIR. A number obtained by adding "1" to the FAT number is written in each FAT. Then, the information indicating the message end is written in the last FAT in the memory. The number of the first FAT in the memory is written in the empty cluster DIR. That is, at the end of the initialization, the entire FAT area is in a continuous state, and if the empty cluster DIR is regarded as one message, the entire memory apparently has a message corresponding to the empty cluster DIR recorded therein.

As described above, the free cluster DIR is a continuous FA corresponding to an unused cluster in the memory.
It has information on the FAT at the beginning of T.

FIG. 3 is a flow chart showing the data recording processing procedure in this embodiment. As shown in FIG.
At the time of data recording, first, the value of the empty cluster DIR is read (step S11), and the value is written in the DIR corresponding to the message number to be recorded this time. And
Data is written in the cluster corresponding to the FAT corresponding to the value (step S12).

When the capacity of the cluster currently being written is full, the FAT number corresponding to the cluster to which data is to be written next is searched for (step S13). The number to be searched is written in the FAT corresponding to the cluster currently being written. Based on that number, the position of the cluster where the data is written next is calculated. When the recording is completed, the number written in the FAT portion corresponding to the cluster in which the data is written last is written in the empty cluster DIR and the end mark is written in the FAT portion.

Next, data reproduction will be described. When reproducing data, first, the value of DIR (FAT number) corresponding to the message number to be reproduced is read, and the data in the cluster corresponding to that value is read. After reading all the data in the same cluster, the FAT number corresponding to the cluster in which the subsequent data is written is searched for. The number to be searched is written in the FAT corresponding to the cluster from which data has been read so far. The position of the cluster in which the next data is written is calculated based on the number.
If the number written in the FAT (fat number corresponding to the cluster in which the continuation of the data is recorded) is the end mark, the writing of the data currently being read is completed there.

As described above, according to the present embodiment, it is possible to reduce the number of FAT searches especially during data recording, which is advantageous when high-speed processing is required.

[0030]

As described above, according to the present invention, by providing an area for managing an unused cluster as one message in the message management area in the memory, data recording can be performed as compared with the conventional method. This has the effect that the number of FAT searches at that time is reduced and high-speed processing becomes possible.

[Brief description of drawings]

FIG. 1 is a configuration diagram of a memory for reproducing a digital signal recording sound according to an embodiment of the present invention.

FIG. 2 is a diagram showing the operation and memory accumulation state of the digital signal recording / reproducing memory in the present embodiment

FIG. 3 is a flowchart showing a recording processing procedure of a digital signal in the present embodiment.

FIG. 4 is a configuration diagram of a digital signal recording / reproducing memory in a conventional example.

FIG. 5 is a flowchart showing a digital signal recording processing procedure in a conventional example.

[Explanation of symbols]

 a DIR part b FAT part c Cluster part d Free cluster DIR

Claims (1)

[Claims] 1. A digital recording / reproducing memory in which a memory area is divided into a certain number of clusters to enable recording, reproduction, and management of a message, which is a group of encoded data, and is one of the memory areas. A message management area is provided in the section, and the message management area is a directory area indicating at least a recording start position in each message memory area, and a file allocation indicating continuity information of a cluster recorded in each message memory area or an empty cluster. A memory for digital signal recording / reproducing, which is divided into a table area and a directory of a free cluster which points to a position of the first file allocation table of the free cluster in the directory area.