Combined memory medium, drive apparatus and method therefor and playback apparatus therefor

A combined memory medium is constructed by an optical disc used as a read-only memory, a cartridge for holding or receiving the optical disc, and a fixed memory which is held in the cartridge. The read or write operation for the fixed memory is carried out by structure different from that used for the optical disc so that the optical disc and the fixed memory constitute an integral memory medium. A combined memory medium drive apparatus includes the combined memory medium, a disc access block for reading out the data on the optical disc, a memory access block for performing reading or writing of data for the fixed memory, and a control block for interpreting an instruction sent from an external device to control the reading of data from the optical disc through the disc access block and the reading or writing of data for the fixed memory through the memory access block, in which the optical disc and the fixed memory are complementarily used. A combined memory medium playback apparatus includes the combined memory medium drive apparatus and a processing block for controlling it to process the data output therefrom, thereby being capable of performing writing. Because the control program is stored in the fixed memory, the drive apparatus and the playback apparatus are able to be operated with the combined memory medium alone, dispensing with the need for another memory medium.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
The present invention relates to a memory medium using an optical disc from 
which information relative to image, sound, character, music, etc. 
previously recorded in applications of hobby, education, business, etc. is 
reproduced in a read-only manner, an apparatus for driving it and an 
apparatus for playing it back. 
2. Description of the Related Art 
In recent years, optical discs have been widely used as a 
recording/reproducing medium for information relative to image, sound, 
character, music, etc. Such optical discs include an optical video disc, 
CDV (Compact Disc Video), etc. for image, sound and music, a CD (Compact 
Disc) for music, a CD-ROM (Compact Disc Read-Only Memory) for computer 
data, a CD-I (Compact Disc Interactive) for multi-media comprising image, 
sound, character, music, computer data, etc. 
Referring to the drawings, one example of an apparatus for driving a memory 
medium using the conventional optical disc mentioned above and that of an 
apparatus for reproducing it will be explained. Now, an English-Japanese 
dictionary system using CD-ROM will be taken as an example. 
FIG. 7 is a block diagram showing an arrangement of the English-Japanese 
dictionary system using the conventional memory medium. In this figure, 
201 is a CD-ROM disc serving as a memory medium; 202 is an access block; 
203 is a control block; 204 is a processing block; 205 is a memory block; 
206 is a memory medium driving apparatus; and 207 is a memory medium 
reproducing apparatus. 
The operation of this system will be explained below. It is assumed that a 
data base of the English-Japanese dictionary is stored in CD-ROM 201 and 
the information retrieved therefrom is stored in memory block 205. Memory 
block 205 is constituted by a floppy disc and a driving device therefor, 
for example. Now, if a specific word is informed to processing block 204 
from the exterior, processing block 204 investigates a position in CD-ROM 
201 corresponding to information of the word from the retrieved 
information stored in memory block 205 and transfers the position 
information to control block 203. Control block 203 controls access block 
202 to output a desired data in CD-ROM 201 and transfers it to processing 
block 204. The structure of CD-ROM 201, data recording format therein and 
method for constructing access block 202 are described in "ASCII", Vol. 
10, No. 4, April 1986, pp 115-124 and Vol. 10, No. 5, May 1986, pp 
105-115. Processing block 204 performs processing required to display the 
coded character on a screen or image plane, for example, to provide the 
information of the specified word. Incidentally, the above processing is 
performed in a manner such that a control program stored in memory block 
205 is previously read out to processing block 204. 
The optical disc used as a memory medium in the above arrangement has the 
following several disadvantages. Information to be stored is prepared 
beforehand. An original disc is cut to record the information therein. 
Then a large amount of duplicates are formed, and they are used as 
read-only devices. Therefore, rewriting of the content thereof and 
addition of new information thereto can not be carried out. The control 
program, which is supplied from another medium, is inconvenient to deal 
with, which makes ambiguous the combination with the optical disc. Even if 
the control program is stored in the optical disc, it is necessary to 
reconstruct the optical disc in order to increase the number of its 
versions. Further, whenever the data output from the optical disc contains 
an error, the data at the same address must be processed in a data error 
detection/correction section. 
SUMMARY OF THE INVENTION 
An object of the present invention is to provide a combined memory medium 
on which writing free from the above disadvantages can be performed, a 
drive apparatus therefor and a playback apparatus therefor. 
In order to attain the above object, the combined memory medium in 
accordance with the present invention is constructed by an optical disc 
used as a read-only memory, a cartridge for holding or receiving the 
optical disc, and a fixed memory held in the cartridge and the read or 
write of which is carried out by means different from that for the optical 
disc so that the optical disc and the fixed memory constitute an integral 
memory medium. The drive apparatus therefor comprises the combined memory 
medium, a disc access block for reading out the data on the optical disc, 
a memory access block for performing the read or write of data for the 
fixed memory, and a control block for interpreting an instruction sent 
from an external device to control the read of data from the optical disc 
through the disc access block and the read or write of data for the fixed 
memory through the memory access block, in which the optical disc and the 
fixed memory are complementarily used. The playback apparatus therefor 
comprises the combined memory medium drive apparatus and a processing 
block for controlling it to process the data output therefrom. The 
combined memory medium drive apparatus further comprises a data error 
detecting/correcting block for detecting a data error included in the data 
read out and correcting it and provides the control block with a function 
that, if the data is not corrected in the data error detecting/correcting 
block, the data is externally output, and, if the data is corrected, the 
corrected data is externally output and also stored in the fixed memory 
through the memory access block so that, in subsequently reading out the 
data at the address where the data error is generated, the corrected data 
is read out from the fixed memory through the memory access block. 
The combined memory in accordance with the present invention is permitted 
to perform the write operation since the optical disc and the fixed memory 
are made integral as mentioned above. By storing a control program in the 
fixed memory, the drive apparatus and the playback apparatus can be 
operated in the presence of only the combined memory medium without 
requiring another memory medium. Further, by storing a correct data of the 
output data with an error, the drive apparatus can be operated with high 
efficiency.

DESCRIPTION OF THE PREFERRED EMBODIMENTS 
Now referring to FIGS. 1 and 2, an explanation will be given for one 
embodiment of the present invention including a combined memory medium, a 
combined memory medium drive apparatus and a combined memory medium 
playback apparatus. 
FIGS. 1a and 1b are block diagrams of a combined memory medium playback 
apparatus in accordance with the present invention, respectively. In FIG. 
1a, 1 is a CD-ROM disk serving as an optical disc; 2 is a fixed memory; 3 
is a disc access block; 4 is a holder; 5 is a control block; 6 is a 
processing unit; 7 is a cartridge; 8 is a combined memory medium drive 
apparatus; 9 is a combined memory medium playback apparatus; 10 is a first 
contact type connector; and 11 is a second contact type connector held in 
holder 4. In such a system, the combined memory medium, which consists of 
cartridge 7, CD-ROM disk 1, first contact type connector 10 and fixed 
memory 2, is adapted to be removable from holder 4. First contact type 
connector 10 will be connected with second contact type connector 11 in 
such a state that the combined memory medium is held or mounted in holder 
4. 
In FIG. 1b, 20 is a first optical pick-up element; 21 is a battery; and 22 
is a second optical pick-up element. The other elements in FIG. 1b are 
referred to by like reference numerals used in FIG. 1a. In such a system, 
first optical pick-up element 20, battery 21 and fixed memory 2 are 
attached to cartridge 7. Further, the combined memory medium, which 
consists of cartridge 7, CD-ROM 1, first optical pick-up element 20, fixed 
memory 2 and battery 21, is adapted to be removable from holder 4. First 
optical pick-up element 20 will be opposite to second optical element 22 
in such a state that the combined memory medium is held in holder 4. 
FIGS. 2a and 2b are a perspective view and a plan view of the combined 
memory medium, respectively, used in the combined memory medium playback 
apparatus of FIG. 1a. As seen from FIGS. 2a and 2b, cartridge 7 holds 
CD-ROM disc 1 therein. Cartridge 7 has a hole 13 for reading out the data 
from CD-ROM disc 1 in its lower surface and a hole 12 for clamping the 
disc in its upper surface. When disc cartridge 7 is mounted in holder 4, 
CD-ROM disc 1 is placed on a turn-table (not shown) in access block 3 and 
clamped there by a disc clamping device (not shown). Thus, CD-ROM disc 1 
and cartridge 7 are kept in a non-contact state, and disc access block 3 
reads out the information stored in CD-ROM disc 1 through read-hole 13 
using a laser beam. On the other hand, fixed memory 2 and first contact 
connector 10, which are fixed to catridge 7, are connected with each other 
through signal lines such as an address line, data line, control line, 
etc. When cartridge 7 is mounted in holder 4, first contact type connector 
10 is connected with second contact type connector 11 and thus control 
block 5 can perform reading or writing of the contents of fixed memory 2. 
FIGS. 2c and 2d are respectively a perspective view and a plan view of the 
combined memory medium playback apparatus of FIG. 16. As seen from FIGS. 
2c and 2d, cartridge 7 holds CD-ROM 1 therein. As in FIGS. 2a and 2b, 
cartridge 7 has a hole 13 for reading out the data from CD-ROM disc 1 in 
its lower surface and a hole 12 for clamping the disc in its upper 
surface. Fixed memory 2 and first optical pick-up element 20 are connected 
with each other through a transmission line and a receiving line. In the 
data reading or writing operation for fixed memory 2, a read or write 
instruction generated from control block 5 is converted into an optical 
signal by second optical pick-up element 22 and the optical signal is 
received by first optical pick-up element 20. The optical signal is 
converted into an electric signal by first optical pick-up element 20 and 
the electric signal is sent to fixed memory 2. Fixed memory 2 incorporates 
therein a memory device and a control circuit for interpreting a read or 
write instruction to perform reading or writing from or into the memory 
device. If the instruction is a write instruction, using a specified 
address and data included in the instruction, the control circuit writes 
the data at the specified address of the memory device. If the instruction 
is a read instruction, the control circuit reads out the data at the 
address of the memory device specified by the instruction and sends the 
read data to control block 5 through first optical pick-up element 20 and 
second optical pick-up element 22. Electric power for fixed memory 2 and 
first optical pick-up element 20 is supplied from battery 21. As fixed 
memory 2, a memory medium which can be accessed at high speed, e.g. a 
semiconductor memory, magnetic bubble memory, etc. serving as a read-only 
memory or a read-write memory is actually used. 
CD-ROM disc 1 and fixed memory 2 are complementarily used. Although CD-ROM 
disk 1 has an advantage of having a larger storage capacity than fixed 
memory 2, it also has disadvantages of being unable to write or rewrite 
data, having a low access speed, being unsuitable for mini-scale 
production, etc. On the other hand, although fixed memory 2 has an 
advantage of being able to write data, having a higher access speed than 
CD-ROM disc 1 and being suitable for mini-scale production, it also has 
disadvantages of having a small storage capacity and being high in the 
cost per one bit. By packaging such two memory media having different 
properties in the same catridge 7, the combined memory medium according to 
the present invention realizes a very efficient memory medium having 
advantages of both media. 
In operation, disc access block 3 reads out the data recorded on CD-ROM 
disc 1 in accordance with an instruction from control block 5 and sends 
the read data to control block 5. 
In accordance with an instruction from processing unit 6, control block 5 
performs the read or write operation of the data in fixed memory 2 through 
first contact type connector 10 and second contact type connector 11 and 
performs the read operation from CD-ROM disc 1 by controlling disc access 
block 3. The data read out from CD-ROM disc 1 is first stored in control 
block 5 and sent to processing unit 6. 
Processing unit 6 serves to process the data sent from control block 5. For 
example, if the sent data is an image data, processing unit 6 converts the 
image data into an image signal and outputs it. 
As described above, in accordance with this embodiment of the present 
invention, a combined memory medium is constructed by the optical disc 
serving as a read-only memory, the cartridge for receiving the optical 
disc therein, and the fixed memory the read or write operation of which is 
carried out through the first contact type connector or the first optical 
pick-up element so that by storing the data for changing or to be added to 
the contents of the read-only optical disc in the fixed memory, the 
combined memory medium itself permits writing. Also, since a cartridge is 
adopted so that the combined memory medium in which the optical disc and 
the fixed memory are integrated with each other is removable from the 
holder, the combined memory medium can be easily exchanged. 
Further, in accordance with this embodiment, a combined memory medium drive 
apparatus is constructed by the combined memory medium, the disc access 
block for reading out the data on the optical disc, the second contact 
type connector or the second optical pick-up element used to perform the 
read or write of data for the fixed memory, and a control block for 
interpreting an instruction sent from an external device to control 
reading of data from the optical disc through the disc access block and 
reading or writing of data from or in the fixed memory through the second 
contact type connector or the second optical pick-up element. And, a 
combined memory medium playback apparatus is constructed by adding, to the 
combined memory medium drive apparatus, the processing unit for 
controlling it to process the data output, therefrom. Therefore, by 
storing, in the fixed memory, a control program for controlling the 
combined memory medium drive apparatus and the combined memory medium 
playback apparatus, the data and control program can be supplied only from 
the combined memory medium without requiring the supply of the control 
program from another medium such as a floppy disc. This makes it easy to 
handle these apparatuses and also eliminates the necessity of considering 
correspondence between the optical disc and the floppy disc. Moreover, if 
the control program is previously stored in the optical disc, another 
control program can be additively recorded in the fixed memory in order to 
effect version-up and so the optical disc may be used as it is. Further, 
if the combined memory medium is mounted in a removable state in the disc 
access block and the memory access means, the combined memory medium can 
be handled as if it were the optical disc. This permits systems in several 
applications of education, hobby, business, etc. to be constructed using 
the combined memory medium containing several kinds of contents. 
Although a CD-ROM was used as the optical disc in this embodiment, it 
should be noted that the invention is not limited thereto; for example, an 
optical video disc may be used alternatively. In the case of using the 
optical pick-up elements, a solar battery can be used as a power supply 
for the fixed memory. 
Referring to FIGS. 3, 4 and 5, a concrete explanation will be given for a 
second embodiment of the present invention in which an English-Japanese 
dictionary is realized using the combined memory playback device according 
to the present invention. In this embodiment, a CD-ROM disc is used as 
optical disc 1 and a ROM (read-only memory) is used as fixed memory 2. 
FIG. 3 is a block diagram of the combined memory medium playback apparatus 
in accordance with the present invention. FIGS. 4a and 4b are schematic 
views showing formats of the data recorded on CD-ROM disc 1. FIG. 4c is a 
schematic view showing a format of the data recorded in fixed memory 2. 
FIG. 5 is a flowchart showing the operation of control block 5. 
First, with reference to FIGS. 4a-4c, an explanation will be given for the 
data recorded in CD-ROM disc 1 and fixed memory 2. CD-ROM disc 1 serves to 
record a general digital data on an area on which music in a compact disc 
is to be recorded, and it is formatted using blocks each consisting of 
2352 bytes as shown in FIG. 4a. Each block consists of, from its head, a 
synchronization signal 101 of 12 bytes, an address data 102 of 4 bytes, 
user's data 103 of 2048 bytes, an error detection code (hereinafter 
referred to as EDC) 104 of 4 bytes, a null data of 8 bytes and an error 
correction code (hereinafter referred to ECC) 105 of 276 bytes. 
Address data (area) 102 records the position of the associated block on 
CD-ROM disc 1. More concretely, address data 102 records the physical 
address of that block in 3 bytes, from the head, using minutes, seconds 
and blocks. 75 blocks correspond to one second in a time unit. 
User's data (area) 103 records word data of the English-Japanese 
dictionary. The record format of the word data is diagramatically shown in 
FIG. 4b. One word data consists of, from the head, areas of a length 106 
of one word (one word=16 bits), a headword 107 and a meaning data 108. 
Length 106 indicates the data amount of these three areas in the number of 
words. 
Headword 107 is recorded as a 8 bit data (1 byte data) consisting of a 7 
bit ASCII code and one bit "0" added at a higher order than it. If the 
data amount of headword 107 is odd bytes, the headword is recorded as even 
byte data by adding one byte null data. Meaning data 108 is recorded in 
Japanese using the sift JIS code in which one character is represented by 
one word. 
Although user's data 103 in one block has a fixed-length, each word data 
has a voluntary-length. Therefore, plural word data may be included in 
user's data 103 of one block or one word data may be extended over user's 
data of plural blocks. However, length 106 and meaning data 107 must be 
necessarily arranged in the same block. To this end, if the edge of user's 
data 103 is located at the boundary between length 106 and headword 107 or 
within headword 107, adjustment is made by inserting null data between the 
previous word data and the associated word data. 
Sift JIS code is a 16 bit code with the most significant bit being always 
1. On the other hand, headword 107 and length 106 have always the most 
significant bit of 0, respectively. Therefore, the boundary between the 
word data can be easily detected by checking the most significant bit of 
the word data. 
The above word data are recorded in an alphabet order from the block of one 
minute zero second zero block. 
FIG. 4c is a schematic view of the format of data recorded in fixed memory 
2. Fixed memory 2 consists of two EPROM's (Erasable Programmable Read Only 
Memory) each having a storage capacity of 32 bytes, thus providing a total 
storage capacity of 64 bytes. A length (area) 109 of 2 bytes starting from 
the address 0 indicates the size of the program recorded from the address 
3 in the number of bytes. An index table start address 110 of 2 bytes 
starting from the address 2 indicates the starting address of the index 
table. The area starting from the address 3 records a program 111 to be 
executed by CPU 60 (see FIG. 3). The area starting from the address 4L 
records an index table 112. Index table 112 indicates correspondence 
between address data 102 and the word data recorded in user's data of the 
associated block. 
Index table 112 is a collection of indexes each having 4 bytes, in which 
one index corresponds to one block in CD-ROM disc 1. Each index is 
provided with an index address assuming the leading index of index table 
112 as zero. The index records therein the leading four characters of the 
headword of the word data recorded in the block corresponding to that 
index in a small character ASCII code. If plural word data exist in one 
block, the headword of the leading word data is used. If the headword is 
shorter than four characters, "a" in the ASCII code is added. If only 
meaning data 108 exists in the block, the same index as the previous index 
is recorded. A null data is recorded to indicate the final position of 
index table 112. 
The data amount of English-Japanese dictionary is generally about 4M byte 
in a small scale dictionary of 500 pages or so, and is about 40M bytes in 
a large scale dictionary of 3000 pages or so. In this embodiment, the data 
amount of character data of 20M byte is assumed. The data amount of 20M 
bytes corresponds to that of 10.sup.3 blocks. If the index of 4 bytes is 
allotted to each of the 10.sup.3 blocks, the capacity of index table 112 
is 40K bytes. Thus, the maximum capacity of program 111 in this embodiment 
is 24K bytes. 
The operation of this embodiment will be explained with reference to FIGS. 
3 and 5. 
In FIG. 3, 31 is an optical pick-up which reads out the data in CD-ROM disc 
1. 32 is a CD signal processing circuit which converts the signal sent 
from optical pick-up 31 into a digital data, thereafter performs error 
correction inherent to CD therefor and the error-corrected data in the 
block as shown in FIG. 4 CD signal processing circuit 32 also separates a 
sub-code data recorded in a time-division manner from an audio data and 
sends it to an access controller 33. The sub-code data records therein a 
sub-code address used to access CD-ROM disc 1 by access controller 33. 
Access controller 33 receives an access instruction from a controller 39 
through a control bus 42 and performs the shift control for optical 
pick-up 31 comparing the received access instruction with the sub-code 
address. Optical pick-up 31, CD signal processing circuit 32 and access 
controller constitute disc access block 3. The operation of this block, 
the sub-code data and the sub-code address will not be explained here, 
since they are discussed in detail in the references mentioned above. 
Control block 5 is constituted by a synchronization detection circuit 34, a 
timing generation circuit 35, an address detection circuit 36, an error 
detection circuit 37, a buffer memory 38, a controller 39 and an interface 
circuit 40. Control block 5, in accordance with an instruction sent from 
processing unit 6 through interface circuit 40, reads out the data from 
CD-ROM disc 1 or fixed memory and sends the read-out data to processing 
unit 6. 
Synchronization detection circuit 34 detects synchronization signal 101 
from the data from CD signal processing circuit 32. This synchronization 
signal resets timing generating circuit 35 to start the operation thereof, 
and then a timing signal is sent to address detection circuit 36 and error 
detection circuit 37, respectively. Address detection circuit 37 detects 
coincidence of address data 102 with a physical address. The physical 
address is set by controller 39 through a control bus 42. Error detection 
circuit 37 executes error detection in a real time using EDC 104. Buffer 
memory 38 stores data in a block except synchronization signal 101. If an 
error is not detected by error detection circuit 37, controller 39 sends 
out only user's data 103 within the block stored in buffer memory 38 to 
processing unit 6 through interface circuit 40. If an error is generated, 
error detection circuit 37 informs controller 39 of the generation of an 
error through control bus 42. Controller 39 executes error correction 
using ECC 105 in the block stored in buffer memory 38. Thereafter, the 
corrected data is sent to processing unit 6 through interface circuit 40. 
If the instruction sent from processing unit 6 is a data read-out 
instruction from fixed memory 2, controller 39 reads out the data in fixed 
memory 2 through first contact type connector 10, second contact type 
connector 11 and data bus 41. The data read out is sent in byte units to 
processing unit 6 through interface circuit 42. The above operation of 
control block 5 is illustrated in a flowchart of FIG. 5. 
Processing unit 6 is constructed by a personal computer comprising a CPU 
(Central Processing Unit) 60, a ROM (Read Only Memory) 61, a RAM (Random 
Access Memory) 62, an I/O port 63, a CRTC (CRT Controller) 64, a V-RAM 
(Video RAM) 65, an I/O port 66 and a key board 67. 
In operation, first, in accordance with a program recorded in ROM 61, CPU 
60 sends out a read-out instruction for fixed memory 2 to control block 5 
through I/O port 63. Control block 5 sends the data shown in FIG. 4 to 
processing unit 6 in the procedure mentioned above. This data is stored in 
RAM 62 through a system bus 68. Thereafter, CPU 60 executes program 111 
stored in RAM 62. Now if CPU 60 is informed of a specific word from 
keyboard 67 through I/O port 66, CPU 60 searches the position of the word 
data in CD-ROM 1 using index table 112 stored in RAM 62 and transfers its 
physical address to control block 5. For example, if the word "grand" is 
input, CPU 60 searches index table 112 and obtains the index address N 
where the word is recorded (see FIG. 4c). This block address N is 
converted to time information consisting of minutes, seconds and blocks. 
In this embodiment, the index address 0 corresponds to one minute, zero 
second, zero block so that the physical address is provided by adding one 
minute, zero second, zero block to the time information. This physical 
address is sent to control block 5. Control block 5 controls disc address 
block 3 in the manner as mentioned above so as to output the desired data 
from CD-ROM 1 and transfers the data to processing unit 6. Processing unit 
6 once stores the received data in RAM 62. CPU 60 retrieves the data to 
detect the word data "grand". CPU 60 converts this word data in a bit map 
data using the font data recorded in ROM 61, and transfers the bit map 
data to V-RAM 65 through CRTC 64. CRTC 64 converts the bit map data stored 
in V-RAM 65 into an image signal 69 and outputs the image data to an 
external device. Image signal 69 is displayed on an external CRT display 
(not shown). 
All of the above successive processings carried out by CPU 60 are described 
on program 111. 
This embodiment realizes a combined memory medium utilizing the 
characteristic of each memory medium in such a manner that character data 
having large capacity and unchanged contents are recorded in CD-ROM disc 
1, whereas the index table having small capacity and a program which 
depends upon the personal computer to be used is recorded in fixed memory 
2. 
Incidentally, although a ROM was used as the fixed memory in this 
embodiment, a write-enable non-volatile memory may be added to the fixed 
memory. In this case, by recording the headword of the retrieved word in 
this non-volatile memory, it is possible to inform a user of the word 
retrieved plural times. Further, although in this embodiment, the program 
executed by the processing unit was recorded in the fixed memory, a 
program to be executed by the control block may be recorded there. 
A third embodiment of the present invention will be explained with 
reference to FIGS. 3, 4a and 6. FIG. 6 is a flowchart showing the flow of 
the processings performed by control block 5. 
Also in this embodiment, CD-ROM disc 1 is used as the optical disc. As the 
fixed memory, a write-enable non-volatile memory is used. In an initial 
state, nothing is recorded there. 
If a read-out instruction for CD-ROM 1 is input, in this initial state, 
from processing unit 6 to control block 5, the data in a desired block is 
stored in buffer memory 38 in the procedure explained in connection with 
the second embodiment. If a data error for this block is not detected by 
error detection circuit 37, user's data 103 is sent to processing unit 6. 
On the other hand, if a data error is detected, controller 39 executes 
error correction for user's data 103 using ECC 105. The error-corrected 
data is sent to processing unit 6 and also written in fixed memory 2 by 
controller 39. Then, controller 39 also writes, in fixed memory 2, address 
data 102 of the block where a data error has been generated. 
Thereafter, when a read-out instruction for CD-ROM 1 is input from 
processing unit 6 to control block 5, controller 39 checks if user's data 
103 in a desired block has been recorded in fixed memory 2. For this 
checking, address data 102 recorded in fixed memory 2 is used. If it is 
found as a result of the checking that a desired data exists in fixed 
memory 2, controller 39 reads out the data and sends it to processing unit 
6. In this case, controller 39 does not read out the data from CD-ROM disc 
1. 
The above-mentioned flow of the processings in control block 5 is such as 
shown in FIG. 6. 
In accordance with this embodiment, the data at the address, where a data 
error has been generated, can be read out from fixed memory, but not from 
the optical disc, and the necessity of executing correction, each time a 
data error for the data at the same is generated, can be removed. 
Although the combined memory medium playback apparatus using contact type 
connectors has been explained in the second and third embodiments, a 
combined memory medium playback apparatus using optical pick-up elements 
instead of the contact type connectors can provide the same effect.