JPH01258288A - Directory retrieving method - Google Patents

Abstract

PURPOSE:To attain high speed directory retrieval and the high speed retrieval of an adding file by executing a retrieving order from a reverse direction to a directory recording order. CONSTITUTION:A directory area 52 is provided in the outside of an optical disk 50 and a data area 51 is provided in the inside of the optical disk. The retrieving order for the directory of the area 52 is executed in the reverse order of the directory recording order. Thus, a directory number to be retrieved at first goes to be the information of the newest file which is finally recorded. Accordingly, it is not necessary to read the information of the directory number to be changed or erased, the high speed directory retrieval can be executed and the access of file data can be executed. Without retrieving all the area 52 for the access of the adding file, only the newest information of the adding file can be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a directory search method, and particularly to a method for searching information files and directories when a non-erasable memory such as an optical disk memory is used.

[Prior art 1: Floppy disk, magnetic hard disk only, large Iil
Directories are used as a file management method for handling file data.

This is used as a heading for file data, including the file name and creation date. It includes the write position 16 (first track number) of the corresponding file data. File data can be easily managed by creating a new directory when new file data is created, and deleting the corresponding directory when unnecessary file data is generated.

In recent years, optical discs have come to be used as data file memory. However, a method for managing changes and erased files on an optical disk that cannot be erased or rewritten cannot be performed in the same way as a memory that can be erased or rewritten.

A conventional method of file search using such an optical disc that cannot be erased or rewritten will be explained.

FIG. 6 is a diagram showing a method using an erase flag.

In this method, "1" is recorded as data indicating that the file has been erased in the erasure flag area of the directory that indicates that the file has changed history or is no longer needed. For example, if the file name "A B C" is changed twice, the deletion flag data "1" indicating deletion is added to the directory "S: ; l" and the directory number "2o".
” is recorded in the erasure flag area, and a new file is additionally recorded in the last directory number: 30. In this case, the deletion flag is not recorded in directory number 3o since it is the newest file.

The directory search method in this conventional example will be described below.

Since the directory search order is the same as the directory recording order, information is read from directory number 1 and the target file name is searched. Next, check the erase flag of the directory number of the target file, and if the erase flag is written, it is an erased file, so read sequentially to the next directory number, and file "A B C" of directory number 30, which does not have an erase flag. Search and mark the file as a valid file.

Next, another conventional method will be explained with reference to FIG.

In the conventional example shown in FIG. 7, in the pointer area of the directory number indicating the changed or deleted file,
This is used to record the directory number in which the new file after the change is recorded. Therefore, a directory number for which nothing is recorded in the pointer area indicates a valid file. Similar to the conventional example shown in FIG. 6, the file search method in this conventional example reads the file "ABC" of directory number 1 and records it in the pointer area because the directory recording order and the search order are the same. Next, the updated directory number 20 is read out. Since a new updated directory number 30 is also recorded in the pointer area of directory number 20, it is known that a 111 history update has been performed. Furthermore, directory number 30 is searched. Since nothing is recorded in the pointer area of directory number 30, it can be seen that the file "ABC" of directory number 30 is the latest file.

[Problems to be Solved by the Invention] However, in the conventional directory search method shown in FIG. When there are many Sid directory directories scattered, or when files have many different histories, there is a problem that the search time for a single file becomes long.Also, the conventional method in Section 7 also has the same problem. Furthermore, when recording the directory of the changed file using the conventional method shown in Figures 6 and 7, after recording the new file in the final directory number, the recorded file number or deletion flag is changed to the previous directory number. It is necessary to search both directory numbers for the same file name and record that information in the pointer area or erasure flag area.
A lot of time is spent recording and searching directories.

Furthermore, when adding (abend) a file, it has a serious drawback in that it is necessary to search for all valid directory numbers with the same file name.

Measures to solve problem E] [1] The present invention only addresses the problems of the above-mentioned prior art.

The object of the present invention is to provide a directory search method that enables high-speed directory search (high-speed file data access) and high-speed search for additional files.

The purpose of the above is that in a directory in which file information related to file data recorded on an information track is recorded, the search order of the directory information is reversed with respect to the order in which directory information related to the file information of the file data is sequentially recorded. This is achieved by a directory search method characterized by the following.

[Operation] According to the directory search method of the present invention, the search order is performed from the reverse direction with respect to the directory recording order, so that the directory number searched first is the latest file recorded last. Therefore, the above-mentioned problem can be solved.

[Example] Hereinafter, the directory search method of the present invention will be described in detail based on a concrete example using the drawings.

First, the format of an optical disc will be explained as an example of a format showing the directory area and data area of the present invention.

FIG. 2 is a configuration diagram showing a directory area of an optical disc having a directory and a method of dividing the data area. The directory area 52 is divided into an area outside the optical disc 50, and the data area 51 is divided into an area inside the optical disc 50.

FIG. 1 shows the structure of a directory used in the directory search method according to the present invention. For example, it is assumed that 50 directories can be recorded in the directory area. The recording direction of the directories in the directory area is such that the directory numbers are recorded in order from directory number 1 in the direction of increasing directory numbers. To record the first file name "ABC", record the file name of the recorded data file, its extension, and attributes, and then
Record the first track number, first sector number, and file size where the file was recorded. Next, necessary directory information is recorded in directory number 2 with the file name "1):", then directory number 3 with the file name "F G II", and so on.

Next, a method of recording directory information when changing or updating the same file will be explained.

According to the directory search method of the present invention, even when changing or updating the same file, it is recorded in the directory number area next to the last directory number recorded using the same method as the file recording method described above. There is no need to search for the directory number of the old file and record the directory number or record the deletion flag.

Furthermore, the case of additional recording of an abend file will be explained.

In the case of an abend file, the necessary information is recorded in the directory number area next to the final directory number using the same method described above for recording a new file, and the abend flag (“
1”) is simultaneously recorded in the abend flag area.

Next, a directory search method according to the present invention using the directory area shown in FIG. 4 will be explained with reference to the flowchart shown in FIG. The flowchart in FIG. 3 shows a case where a file with the file name "ABC" is searched, and addition (abend) of a file is also considered.

According to the present invention. According to the directory search method, the directory search order is performed in the reverse order of the directory recording order.

First, in order to search for the abend file when an addition is made to the target search file, the abend flag count, which stores the number of abend files, is cleared (step S1). Next, the optical head is moved to the maximum directory number 50 in the directory area according to this embodiment, and the information of directory number 50 is read out (step S2). If directory information is not recorded in the read directory number, the optical head is sequentially moved to the direction of the directory number with the smallest number to search for the recorded directory number (step S3).
, 4). If directory information is recorded,
From the recorded directory number information, compare the file name information with the target file name "ABC",
The directory number in which the 1:1 file is recorded is searched (step 35.6). In this case, it is clear that the directory number searched first is the most recent file recorded last. In the directory shown in FIG. 1, directory number C) 30 is detected as the latest (last recorded) file "AI'3C".

Here, when the append flag of directory number 30 is checked (step S7), since the abend flag is "l-", the file "ABC" of directory number 30 is
You can see that this is an added file.

Therefore, 1 is added to the number of abend flags (step S8). At that time, the directory information of the abend directory number shift is also stored (step S
9). This is because it is necessary for one to occur later.

Furthermore, the search continues for the abended previous file "ABC" in the search order direction of FIG. Then, the target file "ABC" is detected at directory number 20. File “Δr3C” with directory number 20
Since no append flag is recorded in , it is detected that the file "ABC-" with directory number 20 is the [1 file] of the song to be added.

The file data of the file "AI'3C" is read from the first track number, the first sector number and the file size in which the file data recorded in the directory number 2() is stored (step 5lO). Then the file “
Since it was previously searched that there was one additional file in "A 13 C", the added file data is read from the stored abend directory information (step 5I2), and the abend flag count is subtracted by 1. (Step 513) By repeating this operation until the number of abend flags becomes zero, all file data of the target file "ABC" including all abend files can be read out.

[Other Embodiments] In the first embodiment, the directory area and the data area were separated into the outside and inside of the optical disc, but they may be separated in five circumferential directions as shown in FIG. may be scattered over the entire disk. Further, FIG. 5 shows a case where an optical card is employed as the recording medium. In FIG. 5, 60 is an optical card, 52 is a directory area, and 51 is a data area.

Note that, as the directory search method of the present invention, the directory search according to the present invention can be achieved if the recording order in which the directories are recorded and the search order in which the directories are searched are substantially reversed.

For example, when the number of recorded files is small, instead of moving the optical head to the highest directory number at once during a search, there is a method of dividing the maximum number of directories into a certain number and searching for the final recorded file in divided units. By doing so, it is possible to shorten the time required to search for the final recorded file.

[Effects of the Invention] As explained above in detail, according to the directory search method according to the present invention, the first file searched according to the search order is updated to the latest file without reading information on old directory numbers that have been changed or deleted. Since it becomes a file, high-speed directory search becomes possible, and as a result, file data can be accessed. Furthermore, when accessing additional files, only the latest additional file information can be obtained without searching all directory areas, so searching for many additional files is also fast.

This effect is especially great for optical disks and optical card memories with large storage capacities, but it is also great for file system systems that handle a large number of directories, and for applications where many changes and deletions are made. It is clear that it is effective.

Note that the erasure of old files according to the present invention does not involve erasing physical directory information, so it is possible to read logically erased files, and it is also possible to take backups during file processing. It also has characteristics.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing the structure of a directory format used for directory searching according to the present invention. FIG. 2 is a diagram showing a method of dividing an optical disc into a directory area and a data area. FIG. 3 shows a flowchart for performing a directory search according to the present invention using the directory search engine shown in FIG. FIG. 4 is a diagram showing another method of dividing the directory area and data area on an optical disc. FIG. 5 is a diagram showing an example of a method of dividing a directory area and a data area in an optical card. FIG. 6 is a conventional directory format used to explain a conventional directory search method. FIG. 7 is a conventional directory format used to explain another conventional directory search method. Figure 4 Figure 5 Figure 3

Claims (2)

[Claims] (1) In a directory in which file information related to file data recorded on an information track is recorded, the search order of the directory information is reverse to the order in which directory information related to the file information of the file data is sequentially recorded. Featured directory search method. (2) A directory search method according to claim 1, characterized in that a recording medium is used in which at least an area for recording directory information is a non-erasable area.