Electrical computers and digital processing systems: memory – Storage accessing and control – Specific memory composition
Reexamination Certificate
2000-03-22
2002-10-15
Yoo, Do Hyun (Department: 2187)
Electrical computers and digital processing systems: memory
Storage accessing and control
Specific memory composition
C711S170000, C711S165000, C345S520000, C345S501000, C710S068000
Reexamination Certificate
active
06467016
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a digital data recording apparatus which performs digital encoding compression on various information signals and records the encoding compressed data on a non-volatile semiconductor memory card, and more particularly, to a digital data recording apparatus which is capable of consecutively recording, without lack of information data, information data such as a moving image or sound which progresses in a time series manner, in empty data areas which discontinuously exist in the non-volatile memory card.
2. Description of the Related Art
In recent years, the recording capacities of non-volatile semiconductor memories have been increasing and the recordable amount of data per non-volatile semiconductor memory has been increasing. Non-volatile semiconductor memories having card-like shapes have been developed, and digital still cameras for recording still images and audio recording equipment which use such cards in place of silver-halide film or audio recording magnetic tape have been developed and put into practice.
This type of digital still camera and audio recording equipment converts an analog signal picked up and generated by a photographic camera or a microphone into a digital signal, performs encoding compression on the digital signal to convert the digital signal into data having a predetermined data format, and records the data on the non-volatile semiconductor memory. The non-volatile semiconductor memory has a data storage area divided into plural physical blocks each of which stores a predetermined amount of data, and is capable of managing recording or erasure of data for each of the physical blocks. In general, in order to enable recorded data to be read and edited on computer equipment, the non-volatile semiconductor memory adopts a data format conforming to MS-DOS which is an OS for computer equipment.
A microprocessor converts the encoding compressed recording data into the data format of MS-DOS and creates management file data relative to the recorded data, and records the encoding compressed recorded data on physical blocks of the non-volatile semiconductor memory. Thus, reading and erasure of data recorded on plural physical blocks are performed by using the file management data.
A specific example of a digital data recording apparatus using the non-volatile semiconductor memory will be described below with reference to
FIGS. 10 and 11
.
FIG. 10
is a block diagram showing the construction of an audio digital data recording/reproducing apparatus, and
FIG. 11
is an explanatory view showing the configuration of physical blocks of the non-volatile semiconductor memory.
An audio input circuit
21
of the audio digital data recording/reproducing apparatus
20
shown in
FIG. 10
is made of a microphone (not shown) which picks up sound such as music or human voice and generates an analog electrical signal, and an amplifier circuit (not shown) which amplifies the analog electrical signal generated by the microphone.
During recording, the analog audio signal generated by the audio input circuit
21
is converted to a digital audio signal by an analog/digital conversion circuit (hereinafter referred to as the A/D circuit)
22
, and the digital audio signal is supplied to an encoding compression circuit
23
. The encoding compression circuit
23
performs encoding compression on the digital audio signal, thereby generating predetermined digital compressed data. The encoding compression in the encoding compression circuit
23
uses the compression technique of G
7
29A which is an ITU (the International Telecommunications Union) standard. The digital encoding compressed data generated by the encoding compression circuit
23
is recorded on a card provided with a non-volatile semiconductor memory (hereinafter referred to as the non-volatile memory card)
25
, via a control means
24
composed of a microprocessor (MPU). As is well known, the microprocessor is also called CPU, and is made of one chip on which are integrated various units such as an arithmetic unit which performs arithmetic and logic operations, a control unit which performs interpretations of instructions and generation of control signals, and a storage unit. The control means
24
exerts control on writing and reading of the digital encoding compressed data to and from the non-volatile memory card
25
, and also generates management data on the written digital encoding compressed data.
During reproduction, the digital encoding compressed data read from the non-volatile memory card
25
under the control of the control means
24
is expanded and decoded by a decoding expansion circuit
26
, whereby the digital encoding compressed data is converted to a digital audio signal. The digital audio signal generated by the decoding expansion circuit
26
is converted to an analog audio signal by a digital/analog conversion circuit (hereinafter referred to as the D/A circuit)
27
, and the analog audio signal is supplied to an audio output circuit
28
made of an amplifier circuit and a speaker (none of which is shown).
An operating switch
29
and a liquid crystal display
30
are connected to the control means
24
. The operating switch
29
serves as an operating input means which has a switch for entering an operation input, such as audio recording, audio reproduction or power-off, into the audio digital data recording/reproducing apparatus
20
. The liquid crystal display
30
displays the operating state of the audio digital data recording/reproducing apparatus
20
according to the input form the operating switch
29
.
Incidentally, the non-volatile memory card
25
is capable of being removably fitted into a card slot provided in the body (not shown) of the audio digital data recording/reproducing apparatus
20
.
The A/D circuit
22
, the encoding compression circuit
23
, the decoding expansion circuit
26
and the D/A circuit
27
are formed as a one-chip audio processing integrated circuit (hereinafter referred to as the audio processing IC).
The recording state of the digital encoding compressed data to be recorded on the non-volatile memory card
25
of the audio digital data recording/reproducing apparatus
20
having the above-described construction will be described below with reference to FIG.
11
.
If the non-volatile semiconductor memory used in the non-volatile memory card
25
has a recording capacity of, for example, 8 Mbytes, the data recording area of the non-volatile semiconductor memory is managed in the state of being divided into 1,024 physical blocks. The state of the physical blocks is schematically shown in FIG.
11
.
Assuming that data are already recorded on physical blocks
0
to
2
, physical blocks
4
and
5
and physical blocks
8
to
1014
in the non-volatile memory card
25
, if new digital encoding compressed data are to be recorded, the physical blocks are searched in order from physical block
0
and the new digital encoding compressed data are sequentially recorded on unrecorded physical blocks. In this case, the shown physical blocks
3
,
6
and
7
are immediately detected by search, but it takes time to detect an unrecorded physical block such as physical block
1015
located near the bottom.
In a digital data recording apparatus provided with the non-volatile memory card
25
, during recording of digital data such as sound or a moving image which progresses in a time series manner, even while an unrecorded physical block is being searched for in the non-volatile memory card
25
, the data progresses, so that there is a possibility that when the data is recorded after an unrecorded physical block has been detected, the data which has progressed during the search may be lost.
Incidentally, each of the clusters shown in
FIG. 11
is a logical minimum unit of a file managed by the FAT (File Allocation Table) file system of MS-DOS which will be described later, and the respective clusters are present to correspond to the physical blocks.
As described above, in the related art, when
Kabushiki Kaisha Toshiba
McLean Kimberly
Yoo Do Hyun
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