JP2002170360A - Digital disk recorder - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a digital disk recorder capable of preventing the page previously read during arbitrary task processing from being deleted during another task processing by performing the management of a main memory device by using a page list in which the pages referenced by an arbitrary task are linked in order of page-in. SOLUTION: This digital disk recorder has a memory management means 22 for instructing the page-in to a paging means 23 when the desired page does not exist on the main memory device 18. When there are no free pages on the main memory device 18 on the occasion of the page-in, the page to be paged out is selected from the pages on the main memory device 18 and the free page instructed of the page-out to the paging means 23 is made. The top page in the page list is selected for the page to be paged out.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a digital disk recorder for decompressing and reproducing compressed and recorded images, and more particularly to controlling management information using a paging method to monitor traffic, traffic, or inside a bank. The present invention relates to a digital disk recorder that captures an image input from a camera or the like, compresses the recorded image, and expands and reproduces the recorded image.

[0002]

2. Description of the Related Art Conventional digital disk recorder 1
As shown in FIG. 16, a video input means 11 for converting a video signal input to the device into a digital signal, and an Audio signal for converting an audio signal input to the device into a digital signal.
o input means 12, Video input means 11 and Audio
o Encoding means 1 for receiving and encoding digital data from input means 12 to generate a digital data stream
3, an image memory 14 for temporarily storing a plurality of digital data streams, and an image memory control means for transferring the digital data stream generated by the encoding means 13 to the image memory 14 or transferring the data to a recording medium 16 15, a recording medium 16 for recording the digital data stream, and a function of writing and reading the digital data stream generated by the encoding means 13 to and from the recording medium 16 and having a function of adding management information together with the digital data stream. File management means 17
And a main storage device 18 for temporarily recording and holding management information.
And a control unit 30 that controls the recording medium 16, the encoding unit 13, and the decoding unit 19 in conjunction with the file management unit 17.
Decoding means 19 for separating the digital data stream recorded on the recording medium 16 into video and audio digital data; a video output means 20 for converting the video digital data into a video signal; Audio output means 21 for converting the signal into a signal. Note that the file structure of the recording medium 16 includes a file defined by the JIS X 0605 standard.
e Allocation Table) type disk format.

A conventional digital disk recorder 1 is:
Video or audio signals input to the device
The input means 11 or the audio input means 12 converts the digital signal into a digital signal, and the encoding means 13 performs data compression.
The data is recorded on the recording medium 16 in chronological order. Also, management information (directory entry, FAT entry) is generated along with the digital data stream, and
To be stored.

In a surveillance system, a surveillance camera is installed at a certain place, and a picture of the place is monitored in real time while being reproduced on a monitor, and the surveillance picture is stored in a digital disk recorder and recorded as necessary. It is a system that enables long-term monitoring by playing back images that have been reproduced. In a monitoring system in which it is desired to simultaneously perform reproduction and search while recording, all management information created on the recording medium is held in a main storage device that can be accessed at high speed, and the recording medium is stored at an arbitrary timing. It is common to record while backing up.

However, the conventional digital disk recorder which records all the management information on a main storage device having only a limited address space and records an image has a problem that the maximum capacity of a magnetic disk or an optical disk is limited. there were. Therefore, a conventional digital disk recorder uses a paging method, which is a method of a virtual storage method, to make the address space of a main storage device look like a virtually larger address space, thereby enabling a large-capacity recording medium with a small memory capacity. Management is possible.

Hitherto, as this kind of virtual storage system, one described in Japanese Patent Application Laid-Open No. 8-161230 has been known. FIG. 17 shows a configuration of a virtual storage system according to a conventional paging method, in which a running program 31 accesses a main storage device 32 and
A page fault is generated when an access is made to a page that is not stored in the storage medium. When a page fault occurs, several pages including the page are read from the recording medium. In this case, the page referred to after the page in the past is stored in the fault history information 38, and when the page fault occurs, if the fault history information 38 exists, the fault history information 38 , And in other cases, the pages are prefetched in the order in which they are stored in the secondary storage device 33, thereby improving the transfer efficiency.

[0007]

However, in such a conventional digital disk recorder having a paging-type virtual storage system, the page table is assigned one entry for each page in the virtual storage space. However, when the storage capacity of the recording medium is expanded, there is a problem that the page table capacity needs to be expanded.

Further, for example, page-in is performed at the time of recording a file, a plurality of pages including reference data are pre-read from a recording medium to a main storage device, and thereafter, file recording and file retrieval are repeatedly performed without performing file recording for a while. In this case, there is a problem that a page read ahead during file recording is deleted from the main storage device.

In addition, file recording, file reproduction, etc.
When processing multiple tasks simultaneously and in parallel, if multiple tasks issue page faults consecutively, and then request digital data writing to a recording medium,
Until all paging processes have been completed, digital data cannot be written to the recording medium, so that the recording speed is reduced.

The present invention has been made to solve such a problem. By allocating entries constituting a page table to pages in a main storage device, even if the storage capacity of a recording medium is expanded, the page size can be increased. An object of the present invention is to provide an excellent digital disk recorder which does not need to expand the table capacity.

Another object of the present invention is to provide an excellent digital disk recorder capable of preventing deletion of a prefetched page by individually managing pages referred to or prefetched for each task.

Further, the present invention provides an excellent digital disk recorder capable of preventing a decrease in recording speed by assigning an execution priority to each task and scheduling a command execution order on a recording medium according to the execution priority. Is provided.

[0013]

SUMMARY OF THE INVENTION A digital disk recorder according to the present invention comprises: a video input means for inputting a video signal and converting it to digital; an audio input means for inputting an audio signal and converting it to digital; A video output means for converting data to a video signal; an audio output means for converting audio digital data to an audio signal; and receiving and encoding digital data from the video input means and the audio input means to generate a digital data stream. Encoding means, a recording medium for recording the digital data stream generated by the encoding means, a decoding means for separating the digital data stream recorded on the recording medium into video and audio digital data, Digital data stream generated by the encoding means The write to the recording medium includes a file management unit performs a control for reading adds management information in conjunction with the digital data stream, and a main memory for temporarily recording holding the management information,
In a digital disk recorder having a paging type virtual storage system, in the main storage device, an address space is divided into pages, and a part of management information stored in the recording medium is mapped onto the pages, and the digital disk is A recorder has a page table including information on data transfer of management information between the main storage device and the recording medium, and a memory management unit that manages the main storage device, and referring to the page table,
Paging means for transferring data of management information in page units between the main storage device and the recording medium is further provided.

With this configuration, by placing only the necessary management information on the main storage device, it is possible to easily cope with the capacity expansion of the recording medium.

Preferably, the page table is composed of the same number of entries as the number of pages on the main storage device, and the memory management means associates the pages on the main storage device with the entries, The entry includes the address of the page on the recording medium transferred to the corresponding page on the main storage device. With this configuration, the page table allocates information about one data transfer for each page in the main storage device, so that the number of information in the page table does not increase even if the storage capacity of the recording medium is expanded. Because you can continue recording,
It is possible to easily cope with the expansion of the capacity of the recording medium.

Preferably, the file management means processes a plurality of tasks simultaneously and in parallel, and the page table includes information indicating a page-in order of a page referred to or a pre-read page during the processing of the task. The “task” includes file recording, file reproduction, file search, and the like.

According to this configuration, for each processing unit of the file management means, information indicating a reference order of pages on the main storage device referred to by the processing unit is included in the page table, so that the main storage allocated to the processing unit is assigned. The page on the device can be known, and the usage status of the page on the main storage device can be easily obtained.

Further, preferably, the memory management means defines the number of assignable pages on the main storage device for each task of the file management means. With this configuration, the required capacity of the main storage device can be easily specified, and the required number of pages on the main storage device can be easily determined.

Preferably, the task of the file management means accesses a page not stored in the main storage device, and the memory management means instructs reading of a group of pages including a page corresponding to the paging means, When the paging unit transfers data of management information in page units from the recording medium to the main storage device in accordance with an instruction from the memory management unit, the memory management unit determines whether the task has a main storage actually reserved by the task. Comparing the number of pages on the device with the number of assignable pages, determining whether it is possible to newly assign a page of the group of read pages to the task, and assigning a page to the task. If it is determined that the task cannot be performed, select a page to be deleted from the pages owned by the task, and Page and out of the page,
The page that has been paged out is set as a storage destination of the group of read pages.

With this configuration, by performing page management for each task, the number of page faults can be reduced, and data transfer efficiency can be improved.

[0021] Further, preferably, the selection of the page to be deleted is to select the oldest page-in page from the pages owned by the task. With this configuration, a page with a high reference frequency can be stored in the main storage device, and the data transfer efficiency can be improved.

Further, the digital disk recorder of the present invention comprises: a video input means for inputting a video signal and converting it to digital; an audio input means for inputting an audio signal and converting it to digital; Video output means for converting digital audio data into audio signals, and audio encoding means for receiving and encoding digital data from the video input means and audio input means to generate a digital data stream. A recording medium for recording the digital data stream generated by the encoding means; a decoding means for separating the digital data stream recorded on the recording medium into video and audio digital data; and The generated digital data stream A digital disk recorder comprising: a file management unit that controls writing and reading to and from a recording medium and adds management information along with the digital data stream; and a main storage device that temporarily records and holds the management information. In the main storage device, the address space is divided into pages, a part of the management information stored in the recording medium is mapped onto the page, and the digital disk recorder is provided between the main storage device and the recording medium. A memory management unit that has a page table including information on data transfer of management information and manages the main storage device, and refers to the page table,
Paging means for performing data transfer of management information in page units between the main storage device and the recording medium, and a command in an execution waiting state issued by the file management means and the paging means to a previous recording medium And a scheduling means for temporarily assembling a command execution sequence on the recording medium.

With this configuration, the order of executing commands on the recording medium can be easily controlled, and a decrease in the recording / reproducing speed can be prevented.

[0024]

Embodiments of the present invention will be described below with reference to the drawings. In all the drawings, similar components are denoted by the same reference symbols and reference numerals, and detailed description will be omitted. (First Embodiment)

As shown in FIG. 1, a digital disk recorder 10 according to a first embodiment of the present invention has a
Input means 11, audio input means 12, encoding means 13, image memory 14, image memory control means 15
, A recording medium 16, a file management unit 17, a main storage unit 18, a decryption unit 19, and a video output unit 2.
0, Audio output means 21, Memory management means 22
And paging means 23.

The recording medium 16 is a hard disk (HD)
This is a recording device that can be accessed at high speed as in D).
It consists of one or more devices. The digital data recorded on the recording medium 16 has been subjected to intra-frame compression such as JPEG or inter-frame compression such as MPEG.

In the present embodiment, an example is shown in which the FAT disk format is adopted for the file structure of the recording medium 16, and the directory entry area and the FAT area are used as paging target areas. The paging target area (virtual address space) of the recording medium 16 is divided into pages,
It is managed on a page basis. The main storage device 18 is also divided into pages and managed in page units, similarly to the virtual address space. The page size of the virtual address space and the page size of the main storage device 18 are the same.

The memory management means 22 manages the main storage device 18 and, for example, allocates and releases pages, manages empty pages, and the like. Memory management means 2
Reference numeral 2 designates page-in to the paging means 23 when the target page is not on the main storage device 18. When there is no empty page in the main storage device 18 at the time of page-in, a page to be paged out is selected from pages in the main storage device 18 and a page-out is instructed to the paging means 23 to create an empty page. . Further, memory management means 2
Reference numeral 2 has a page table for associating a page in the virtual address space with a page in the main storage device 18, and an address conversion from a virtual address to a physical address is performed using this page table.

The paging means 23 is a memory management means 2
2, the data of the management information is transferred between the main storage device 18 and the recording medium 16 in page units.

In this embodiment, the FAT is used.
It can be applied to a disc format having another hierarchical file structure.

Next, a recording procedure and a reproducing procedure in the digital disk recorder of the present embodiment will be described.

First, the recording procedure of the digital data stream will be described. When a video signal or an audio signal is input, the Video input means 11 and the Audio input means 12 convert the data into digital data, and
To generate a digital data stream. The image memory control unit 15 stores the digital data stream generated by the encoding unit 13 in the image memory 14 and instructs the file management unit 17 to write the digital data stream to the recording medium 16.

In response to the write instruction from the image memory control means 15, the file management means 17 writes the digital data stream to the recording medium 16 and generates management information in accordance with the digital data stream. The file management unit 17 instructs the memory management unit 22 to perform an address conversion from a virtual address to a physical address in order to store the generated management information in the main storage device 18. The virtual address indicates the storage location of the management information in the virtual address space. Upon receiving the address conversion instruction from the file management unit 17, the memory management unit 22 refers to the page table and checks whether a page including the specified virtual address exists in the main storage device 18.

When there is no page containing the management information in the main storage device 18, the page-in is instructed to the paging means 23. The paging unit 23 receives the page-in instruction from the memory management unit 22, and transfers the corresponding page on the recording medium 16 to a predetermined page on the main storage device 18 designated by the memory management unit 22. When the page-in is completed, the memory management unit 22 obtains the storage location (physical address) of the management information on the main storage device 18 and returns the storage location to the file management unit 17. The file management unit 17 stores management information based on the physical address returned from the memory management unit 22.

Next, a procedure for reproducing a digital data stream will be described. The file management means 17 instructs the memory management means 22 to perform an address conversion from a virtual address to a physical address in order to refer to management information corresponding to the digital data stream to be reproduced. Upon receiving the address conversion instruction from the file management unit 17, the memory management unit 22 refers to the page table and checks whether a page including the specified virtual address exists in the main storage device 18.

When there is no page containing the management information in the main storage device 18, the page-in is instructed to the paging means 23. The paging unit 23 receives the page-in instruction from the memory management unit 22, and transfers the corresponding page on the recording medium 16 to a predetermined page on the main storage device 18 designated by the memory management unit 22. When the page-in is completed, the memory management unit 22 obtains the storage location (physical address) of the management information on the main storage device 18 and returns the storage location to the file management unit 17.

The file management means 17 is the memory management means 2
In accordance with the physical address returned from the main storage device 1
8, the digital data stream is read from the recording medium 16, the digital data stream is separated into video and audio digital data by the decoding means 19, and the video output means 20 or Audio is output.
The output means 21 converts the digital data into a video signal or an audio signal.

Next, the paging operation of this embodiment will be described with reference to FIGS.

FIG. 2 is an explanatory diagram of an example of the page table. The page table 40 shown in FIG. 2 stores, for each page allocated to the real address space of the main storage device 18,
One entry is assigned. One entry includes a real address section 41, a virtual address section 42, an update flag section 43, and an existence flag section 44.

The virtual address section 42 holds an address (page number) of a page in a virtual address space held by a page on the main storage device 18. As shown in FIG. 3, the virtual address 45 is composed of a page number section 46 and an in-page address section 47, and the file management section 17 instructs the memory management section 22 to convert the virtual address 45 into a physical address. In this case, the memory management unit 22 determines that the page number portion 46 of the virtual address 45
, A corresponding entry is searched from the entries of the page table 40.

The update flag section 43 records that data has been updated for a page on the main storage device 18. That is, when the page is paged in, the update flag section 43 is cleared as an initial state, and a mark (“M” in the figure) is added when data is updated for the page in the main storage device 18. Cleared when paged out.

The presence flag section 44 records that a page in the virtual address space is read in a page on the main storage device 18. That is, the main storage device 1
A mark ("P" in the figure) is attached when a page in the virtual address space is paged in to the page No. 8 and cleared when the page is out.

In the example shown in FIG.
Is composed of N entries (Ar0 to ArN-1). The number of entries in the page table 40 and the number of pages on the main storage device 18 are the same, and the real address space on the main storage device 18 is divided into N pages.

Now, the page Av1 in the virtual address space
0, Av11, Av1, and Av30 are paged in pages Ar0, Ar1, Ar3, and ArN-1, respectively, on the main storage device. Further, a mark indicating that a page in the virtual address space has been read is recorded in the existence flag 44 of the corresponding entry. Page Ar1 and Page A
Since data has been updated for the page transferred to rN-1, the update flag of the corresponding entry is marked.

When the memory management unit 22 is instructed by the file management unit 17 to perform the address conversion from the virtual address to the physical address, the memory management unit 22 first refers to the virtual address section of the page table and corresponds to the page number section of the virtual address. Search to find if there is an entry to be made. If there is no corresponding entry, the memory management unit 22 instructs the paging unit 23 to page in. At this time, if there is no empty page in the main storage device 18, a page to be paged out is selected from the main storage device 18 prior to page-in, and a page-out is instructed to the paging means 23, and the empty page is instructed. make. If a corresponding entry exists, the memory management unit 22 performs address conversion from a virtual address to a physical address.

FIG. 4 is an explanatory diagram of an example of address conversion. The received virtual address 45 is the page number Av11
And in-page address α. Memory management means 2
2 replaces the page number 46 of the virtual address 45 with the page number Ar1 in the real address space corresponding to the entry detected in the page table 40, and replaces the physical address 48
Generate

FIG. 5 is a flowchart illustrating an example of a page-in operation of the digital disk recorder according to the present embodiment.

In step S101, the main storage device 1
8 detects that a page that is not resident on the server is referenced.
When the reference is detected, in step S102, the memory management unit 22 checks a free page. When the empty page is confirmed, the process proceeds to step S104, and instructs the paging means 23 to page in the referenced page.

The paging means 23 is the memory management means 2
When the page-in instruction is received from Step 2, Step S10
Proceed to 5 to select a page to be paged in from the recording medium 16. At this time, a group of pages including the reference page may be collectively pre-read. The pre-reading here means that a page to be referred to in the future is loaded on the main storage device in advance. Since the file management means 17 records the digital data stream on the recording medium 16 in chronological order, the management information created along with the digital data stream is also stored in the management information area (FAT area or directory entry area) on the recording medium 16. )
Are stored continuously from the beginning of Then, at the time of page-in, the transfer efficiency is improved by reading the continuous pages collectively into the main storage device 18 starting from the reference page.

In step S102, the main storage device 1
If there are no or few empty pages on 8,
Proceeding to step S103, page out is performed and then page in is performed. If the number of free pages in the main storage device is smaller than the number of pages to be paged in, it is necessary to page out.

In step S106, the paging unit 23 instructs the memory management unit 22 to secure a page on the main storage device where the page to be paged in is stored. The memory management unit 22 receives the instruction from the paging unit 23 and specifies the storage destination of the page to be paged in. Next, in step S107, the paging means 23 stores the necessary page on the recording medium 16 in the main storage device 1.
8 to a predetermined page.

FIG. 6 is a flowchart illustrating an example of a page-out operation of the digital disk recorder according to the present embodiment.

In step S201, the memory management means 22 instructs the paging means 23 to page out. Further, the memory management unit 22 determines in step S20
In step 2, a page to be paged out is selected. The page to be paged out may be selected by the paging means 23.

In step S203, if the selected page has not been updated, the paging means 23 simply releases it as a free page, and if it has been updated, performs data transfer to the recording medium 16. From the change mark attached to the update flag section 43 of the page table 40, it can be seen that the selected page has been changed. In step S204, the update flag section 43 of the page table 40 is cleared.

The paging means 23 determines in step S205
Instructs the memory management unit 22 to release the page that has been paged out on the main storage device 18. Step S
In 206, the memory management unit 22 sets the page that has been paged out as a free page. Page table 40
By clearing the existence flag 44, the corresponding page can be changed to an empty page.

As described above, in the digital disk recorder according to the first embodiment of the present invention, the management information area on the recording medium is divided into areas having a certain storage capacity, that is, in units of pages. By arranging the page including the management information on the main storage device, it is possible to easily cope with the capacity expansion of the recording medium. Also, by allocating one entry in the page table for each page on the main storage device, the page table capacity becomes constant,
It is possible to easily cope with the expansion of the capacity of the recording medium.
(Second embodiment)

Next, a second embodiment of the present invention will be described.

According to the second embodiment of the present invention, the memory management means 22 shown in the first embodiment of the present invention uses the page or the page-in At this time, a page list is formed by linking pre-read pages in the order of page-in, and the main storage device 18 is managed using the page list.

The memory management means 22 manages the main storage device 18, for example, allocates and releases pages, manages empty pages, and the like. When the target page is not on the main storage device 18, the memory management unit 22 instructs the paging unit 23 to page in. When there is no empty page in the main storage device 18 at the time of page-in, a page to be paged out is selected from pages in the main storage device 18 and a page-out is instructed to the paging means 23 to create an empty page. . The first page in the page list is selected as the page to be paged out. The memory management means 22 has a page table for associating pages in the virtual address space with pages in the main storage device 18. Further, it has a page list management table for managing a page list.

Hereinafter, the paging operation of this embodiment will be described with reference to FIGS.

FIG. 7 is an explanatory diagram of an example of the page table 50 in the present embodiment. The page table 50 according to the present embodiment is different from the page table 40 according to the first embodiment in that a page referred to by an arbitrary task of the file management unit 17 or a page read ahead at the time of page-in. The difference is that a link address section 51 indicating the page-in order is provided. Link address section 51
Holds the address (page number) of the page that has been paged in next to the page on the main storage device 18. However, if the page on the main storage device 18 is the end of the link, information indicating the end is recorded.

In the example shown in FIG. 7, pages Av10, Av11, Av1, and Av30 on the virtual address space are pages Ar0, Ar1, Ar3, ArN on main memory 18.
-1 are respectively page-in. Further, a mark indicating that a page in the virtual address space has been read is recorded in the existence flag 44 of the corresponding entry. Here, it is assumed that pages Ar0, Ar1, and Ar2 are the recording task of the file management unit 17, and page ArN-1 is the page referred to by the reproduction task or the page read in advance at the time of page-in. NULL at the link destination indicates the end of the link.

Pages Ar0, Ar on main storage device 18
1. Ar3 is a page referred to by the recording task or a page for which the memory management unit 22 instructs the paging unit 23 to prefetch at the time of page-in, and the pages are arranged in the order of page-in (Ar0 → Ar1 → Ar3). Form a list. The page Ar3 is the last page in the page list, and information indicating the end of the page list is recorded in the link address section 51 of the entry corresponding to that page. In addition, page ArN-1
Is a page referred to by the reproduction task, and information indicating the end of the page list is recorded in the link address section 51 of the entry corresponding to the page.

The memory management means 22 forms the page list for each task processed by the file management means 17, for example, a recording task, a reproduction task, and a search task.
The page targeted for an arbitrary task is stored in the main storage device 18.
Above, and if the page is linked to the page list of another task, the memory management means 22 can refer to the target page on the main storage device 18 by any task.
Do not link to the page list.

FIG. 8 is an explanatory diagram of an example of the page list management table 60. In the page list management table 60 shown in FIG. 8, one entry is assigned to each page list. One entry is composed of 61 allocated pages, 62 linked pages, a start address section 63, and an end address section 64.

The number of allocated pages 61 records the number of pages on the main storage device 18 that can be linked to the page list. The number of allocated pages 61 is the file management means 17
Is defined by the memory management means 22 in accordance with the task type.

As the number of linked pages 62, pages on the main storage device 18 linked to the page list are recorded.

The head address section 63 holds the address (page number) of the head page in the page list. The memory management unit 22 forms a page list in the order of page-in, and the first page in the page list is the page that is the oldest page in the page list.

The end address section 64 holds the address (page number) of the end page in the page list. The page on the main storage device 18 corresponding to the end address is the most recently page-in page in the page list.

An example of the paging operation of the present embodiment will be described with reference to FIGS. 9 to 11
FIG. 9 is an explanatory diagram showing an example of an operation of a page table 50 and a page list management table 60 associated with a paging operation. FIG. 12 is a flowchart illustrating the page-in operation of the digital disk recorder of the present embodiment, and FIG. 13 is a flowchart illustrating the page-out operation of the digital disk recorder of the present embodiment.

Assume that pages Av0, Av1, and Av2 in the virtual address space are loaded into pages Ar0, Ar1, and Ar2 on the main storage device 18 as shown in FIG. 9A. In the present embodiment, the tasks to be subjected to paging management are “recording task”, “playback task”, and “search task”. Pages Ar0, Ar1,
Ar2 has been paged in during the processing of the recording task, and is linked to the page list of the recording task.
The contents of the page list management table 60 in this state are shown in FIG. Here, the real address space on the main storage device 18 is managed by being divided into 10 pages, of which three pages are allocated to the page list corresponding to the recording task and the reproduction task, respectively. Four pages are assigned to the page list corresponding to the task.

As shown in FIG. 12, file management means 1
When the recording task No. 7 refers to the page Av13 in the virtual address space not resident on the main storage device 18 (step S301), the memory management unit 22 extracts an entry corresponding to the recording task from the page list management table 60, After confirming whether or not an empty page can be assigned to the page list (step S302), it instructs the paging means 23 to page in the referenced page (step S304).

If a free page cannot be allocated to the page list corresponding to the recording task, the memory management means 22 performs page out and then page in (step S303). Whether or not an empty page can be assigned to the page list can be determined from the difference result between the assigned page number 61 and the linked page number 62 in the page list management table 60 (= assigned page number 61−linked page number 62). . If the difference is smaller than the number of pages to be paged in, the memory management unit 22 instructs the paging unit 23 to page out. From FIG. 9B, since the difference between the number 61 of allocated pages and the number 62 of linked pages of the page list corresponding to the recording task is 0,
The memory management means 22 instructs the paging means 23 to page out. The page-out processing will be described later.

The paging means 23 is the memory management means 22
When a page-in instruction is received from the storage medium 16, a page to be page-in from the recording medium 16 is selected (step S30).
5). The paging means 23 is a main storage device 1 serving as a storage destination.
8 is instructed to the memory management means 22 to secure the page on the memory 8.
In response to the instruction from the paging unit 23, the memory management unit 22 specifies a page on the main storage device 18 where the page to be paged in is stored (step S306).
At this time, the memory management unit 22 specifies the page Ar3 from the empty pages on the main storage device 18. The paging means 23 loads the page Av13 on the recording medium 16 into the page Ar3 of the main storage device 18 (step S30).
7).

When the page management is completed, the memory management unit 22 links the page Ar3 to the page list.
The address (page number) of the page Ar3 is recorded in the link address part 51 of the corresponding entry in the page table 50 corresponding to the page Ar2 (step S308). Further, the link page number 62 and the end address part 64 of the corresponding entry in the page list management table 60 are updated (step S309). Page table 5 in this state
0 and the contents of the page list management table 60 are shown in FIG.

Next, the page-out operation will be described with reference to FIG.

The memory management means 22 includes the paging means 2
3 is instructed to page out (step S40).
1). Further, the memory management unit 22 selects a page to be paged out (step S402). The page to be paged out may be selected by the paging means 23. Here, the first page Ar0 in the page list corresponding to the recording task is selected.

The paging means 23 is the memory management means 22
Page-out in response to a page-out instruction from. If the selected page has not been updated, the paging unit 23 simply releases it as a free page, and if it has been updated, performs data transfer to the recording medium 16 (step S403). From the change mark attached to the update flag section 43 of the page table 50, it can be seen that the selected page has been changed. Page Ar
In the case of paging means 2, since the data is updated,
3 transfers the content of the page Ar3 to the recording medium 16. In step S404, the update flag section 43 of the page table 50 is cleared.

The paging means 23 instructs the memory management means 22 to release the page Ar3 on the main storage device 18 which has been paged out (step S405). The memory management unit 22 regards the page that has been paged out as a free page. By clearing the existence flag 44 of the page table 50, the corresponding page can be changed to a free page. In order to delete a page that has been paged out from the page list corresponding to the recording task, the number of linked pages of the corresponding entry in the page list management table 60 is 6
2. Update the start address section 63 (step S40)
6). FIG. 11 shows the contents of the page table 50 and the page list management table 60 in this state.

As described above, according to the second embodiment of the present invention, a page list in which pages referred to by an arbitrary task or pages pre-read at the time of page-in are linked in the page-in order is formed. Also, by specifying the number of pages that can be allocated to that page for each page list,
It is possible to prevent a page read ahead during processing of an arbitrary task from being deleted during processing of another task.

In the present embodiment, the page list is formed for each task. However, the page list is formed for each management information type referred to by each task, for example, for each FAT or directory entry. You may do so. (Third embodiment)

FIG. 14 is a block diagram showing a configuration of a digital disk recorder according to the third embodiment of the present invention. As shown in FIG.
00, the digital disk recorder 10 shown in FIG.
In addition to the above configuration, there is provided an execution waiting command storage unit 131 for storing commands in an execution waiting state, and a scheduling unit 132 for assembling the command execution order on the recording medium 16.

Hereinafter, the operation of the digital disk recorder according to the present embodiment will be described with reference to FIG.

The file management means 17 can process a plurality of tasks simultaneously and in parallel. For example, it can record a plurality of files at the same time, and can play back or search while recording. When the recording task receives the instruction to write the digital data stream from the image memory control unit 15, it issues a command to write to the recording medium 16.

When the reproduction task receives the instruction to read the digital data stream, it issues a command for reading the digital data stream designated to be reproduced from the recording medium 16. When the task refers to the management information and the page requested to be referred to is not in the main storage device, the paging unit 23 issues a command for reading the page to the recording medium 16. If there is no free page in the main storage device 18, the paging means 23 issues a command for writing a page to the recording medium 16.

The command issued to the recording medium 16 is sent to the execution waiting command storage means 131.
This operation will be described with reference to FIG. The execution waiting command storage unit 131 is provided with a command storage unit 140 for temporarily storing a command for each task type in order to separate and manage each task type of the command issuing source. For example, the command issued by the recording task is stored in the recording command storage unit 141. When the recording task refers to the management information and the paging means 23 issues a command for reading a page including the management information to the recording medium 16, the command is stored in the recording command storage unit 1.
41. Here, the command storage unit 140 is configured to store commands in the order of command issuance, and retrieve commands in the order of storage.

When the operation state of the recording medium 16 transitions to the idle state, the scheduling means 132 selects a command to be executed from the commands stored in the execution waiting command storage means 131. The scheduling means 132 assigns an execution priority for each task type. For example, recording task> reproduction task> search task. The scheduling unit 132 acquires an execution waiting command from the corresponding command storage unit 140 according to the execution priority assigned to each command type, and executes the acquired command.

The command storage section 140 is provided with two execution levels (execution level 1 and execution level 2). When the number of commands stored in the command storage unit 140 exceeds the execution level 2, the scheduling unit 132 changes the execution priority of the corresponding command type to the highest, and the number of commands in the command storage unit 140 becomes Processing is performed preferentially until execution level 1 is reached. It is preferable to set the optimum values for the execution level 1 and the execution level 2 for each task type.

As described above, according to the third embodiment of the present invention, the execution priority is assigned to each task type, and the command execution order for the recording medium is scheduled in accordance with the execution priority, whereby the recording is performed. A decrease in speed can be prevented.

[0090]

As described above, according to the present invention, only the necessary management information is stored in the main storage device, so that the storage capacity of the main storage device is not expanded even if the storage capacity of the recording medium is expanded. It is therefore possible to provide a digital disk recorder having an excellent effect that recording can be continued.

[Brief description of the drawings]

FIG. 1 is a block diagram of a digital disk recorder according to a first embodiment of the present invention.

FIG. 2 is a configuration diagram of a page table according to the first embodiment of the present invention.

FIG. 3 is a configuration diagram of a virtual address according to the first embodiment of the present invention;

FIG. 4 is an explanatory diagram of address conversion according to the first embodiment of the present invention;

FIG. 5 is a flowchart of a page-in operation according to the first embodiment of the present invention.

FIG. 6 is a flowchart of a page-out operation according to the first embodiment of the present invention.

FIG. 7 is a configuration diagram of a page table according to the second embodiment of the present invention.

FIG. 8 is a configuration diagram of a page list management table according to the second embodiment of the present invention.

FIG. 9 is an explanatory diagram of a paging operation according to the second embodiment of the present invention.

FIG. 10 is an explanatory diagram of a paging operation according to the second embodiment of the present invention.

FIG. 11 is an explanatory diagram of a paging operation according to the second embodiment of the present invention.

FIG. 12 is a flowchart of a page-in operation according to the second embodiment of the present invention;

FIG. 13 is a flowchart of a page-out operation according to the second embodiment of the present invention.

FIG. 14 is a block diagram of a digital disk recorder according to a third embodiment of the present invention.

15 is an explanatory diagram of command scheduling in the digital disk recorder shown in FIG.

FIG. 16 is a block diagram of a conventional digital disk recorder.

FIG. 17 is a block diagram of a conventional paging type virtual storage system.

[Explanation of symbols]

 10, 100 Digital disk recorder 11 Video input means (video input means) 12 Audio input means (audio input means) 13 Encoding means 14 Image memory 15 Image memory control means 16 Recording medium 17 File management means 18 Main storage device 19 Decoding Means 20 Video output means (video output means) 21 Audio output means (audio output means) 22 Memory management means 23 Paging means 40, 50 Page table 41 Real address part 42 Virtual address part 43 Update flag part 44 Presence flag part 45 Virtual address 46 Page number part 47 In-page address part 48 Physical address 51 Link address part 60 Page list management table 61 Number of allocated pages 62 Number of linked pages 63 Start address part 64 End address 131 awaiting execution command storage means 132 scheduling unit 140 command storage unit 141 recording command storage unit 143 reproducing command storage unit 145 searches for the command storage unit

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Yoshito Aoki 4-3-1 Tsunashimahigashi, Kohoku-ku, Yokohama-shi, Kanagawa F-term in Matsushita Communication Industrial Co., Ltd. 5B005 JJ11 LL15 MM31 NN22 QQ00 5B082 CA08 FA02 5D044 DE12 DE38 DE96 EF05 FG10 FG18 GK08 5D077 AA22 AA30 BA18 BB07 CA02 DC01 EA22 EA33 EA34 FA08 HC02 HC12 5D110 AA13 AA27 AA29 BB27 BC05 DA03 DA06 DA11 DB08 DC05 DC06 DC16

Claims (7)

[Claims] 1. Video input means for inputting a video signal and converting it to digital; audio input means for inputting an audio signal and converting it to digital; video output means for converting digital video data to a video signal; Audio output means for converting audio digital data into an audio signal; encoding means for receiving and encoding digital data from the video input means and the audio input means to generate a digital data stream; A recording medium for recording the digital data stream thus recorded; decoding means for separating the digital data stream recorded on the recording medium into video and audio digital data; and a digital data stream generated by the encoding means. When writing and reading control on the recording medium are performed A file management means for adding management information in addition to the digital data stream, and a main storage device for temporarily recording and holding the management information; In the main storage device, the address space is divided into pages, and a part of the management information stored in the recording medium is mapped onto the page, and the digital disk recorder is provided between the main storage device and the recording medium. A memory management means for managing the main storage device, comprising a page table including information on data transfer of the management information, and a page unit between the main storage device and the recording medium with reference to the page table. And paging means for transferring data of management information in the digital device. Disk recorder. 2. The page table includes the same number of entries as the number of pages on the main storage device, wherein the memory management means associates the pages on the main storage device with the entries, and the entry is 2. The digital disk recorder according to claim 1, further comprising an address of the page on the recording medium transferred to a corresponding page on the main storage device. 3. The file management means processes a plurality of tasks simultaneously and in parallel, and the page table includes information indicating a page-in order of a page referred to during processing of the task or a pre-read page. 2. The digital disk recorder according to claim 1, wherein: 4. The digital disk recorder according to claim 1, wherein said memory management means defines the number of assignable pages on a main storage device for each task of said file management means. 5. A task of the file management means accesses a page not stored in the main storage device, wherein the memory management means instructs reading of a group of pages including a page corresponding to the paging means, When the means performs data transfer of management information in page units from the recording medium to the main storage device in accordance with an instruction from the memory management means, the memory management means stores the data on the main storage device actually secured by the task. Comparing the number of pages and the number of allocatable pages to determine whether it is possible to newly allocate pages of the group of read pages to the task, and cannot allocate pages to the task. If it is determined that, from the pages owned by the task, select the page to be deleted, the selected page Jiauto, and digital disk recorder according to claim 1, characterized in that said page-out page group storage destination of the pages loaded above. 6. The digital disk recorder according to claim 1, wherein the page to be deleted is selected from the pages owned by the task and the oldest page-in page. 7. Video input means for inputting a video signal and converting it to digital; audio input means for inputting an audio signal and converting it to digital; video output means for converting digital video data to a video signal; Audio output means for converting audio digital data into an audio signal; encoding means for receiving and encoding digital data from the video input means and the audio input means to generate a digital data stream; A recording medium for recording the digital data stream thus recorded; decoding means for separating the digital data stream recorded on the recording medium into video and audio digital data; and a digital data stream generated by the encoding means. When writing and reading control on the recording medium are performed A digital disk recorder further comprising: file management means for adding management information along with the digital data stream; and a main storage device for temporarily recording and holding the management information. Divided into pages, a part of the management information stored on the recording medium is mapped onto the page, and the digital disk recorder stores information on data transfer of management information between the main storage device and the recording medium. A memory management unit that has a page table that includes the storage device and that manages the main storage device; and performs data transfer of management information in page units between the main storage device and the recording medium with reference to the page table. Paging means, an execution waiting state issued by the file management means and the paging means to a previous recording medium A digital disk recorder further comprising: an execution waiting command storage unit for temporarily holding a command in a state; and a scheduling unit for assembling a command execution order on the recording medium.