JPH0256021A - Managing system for disk data - Google Patents

Abstract

PURPOSE:To efficiently utilize a file area by eliminating the write of an unnecessary part by using a DRAW (Direct Read After Write) type medium and updating a necessary area only once at the time of registering one file. CONSTITUTION:An FAT 10 and a directory area 11 are areas which are added and updated whenever read/write of a file are executed, and in order to correspond to the DRAW type medium, the capacity being sufficient for executing rewrite of these areas is secured continuously and fixedly in an adjacent area of a disk. Also, this area 11 is an area for storing a file name and its piece number portion is secured by 32 bytes each for registering one file. In this regard, between the directory area 11 and a file area 12, a blanch sector part 13 of a 5-track portion is provided, and a detection time of a boundary is shortened. Moreover, the FAT area 10 stores chain information of a saving block of data. In such a manner, by only updating the area 11 only once at the time of registering one file, a DRAW type disk can be placed under the management of a general purpose OS.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a disk data management system, and in particular, in recent years, due to the large capacity, access speed, and data transfer speed of computers such as 10g software, the present invention relates to a disk data management system. Write-once type (Writ1310) is attracting attention as a recording medium for not only data but also various data such as image data and music data.
This invention relates to a disk data management method suitable for disks (hereinafter referred to as W10).

(Prior Art) Conventionally, disks such as floppy disks and hard disks have been widely used as recording media for recording digital data such as computer programs. The recording format of these disks differs depending on the operating system (O8) installed in the computer, and different O8s are usually not compatible, but with any O8, the external storage device can store data. It is assumed that data can be erased and rewritten, and the storage area of the disk is clearly divided into a file area for recording data and a directory area for recording information related to that data, and formatting is performed in advance. It has been done.

FIG. 10 schematically shows a recording area on a flexible disk such as a floppy disk, for example, the upper part of the figure corresponds to the outer circumference of the flexible disk, and the lower part corresponds to the inner circumference. Reserved area 1 is an area where the system records necessary data and cannot be used by the user. 2 is a FAT (File A11ocatio)
2 is an area for recording data related to file arrangement. 3 is the directory (
DIR) 11 area, and in this area 3, the date, file name, etc. of the data file recorded in the file area 4 are recorded.

Specific examples will be described below with reference to FIGS. 10 and 11.

First, for convenience, the file area 4 in which data is actually stored is divided into a plurality of blocks, and the blocks are sequentially numbered from 2 onwards.

Next, as the FAT area 2, for example, when one block is represented by 12 bits, a data capacity of 12 bits (number of blocks + 2) is secured, and as the DIR area 3, a fixed area of 32 bytes per file is secured. Here, the capacity of each area is a multiple of the sector size.4 The procedure for creating one file is to first record the first block number in file area 4, where the file name and data will be stored, in fixed-length DIR area 3. Then, the data is stored in a predetermined block in the file area 4, and when the data spans multiple blocks, its chain information is recorded in the FAT area 2.

In this way, general-purpose O8 uses FAT, directory (DIR)
) on the disk and main RAM,
When reading/writing data, the file is managed by adding and updating the area. Note that data is written/written on a disk in units of a fixed length called a sector. This management method assumes a freely readable/writable medium (FAT and directories). (Rewriting the area to WIs) It cannot be used as is for write-once optical discs that can only be written once.

Figure 11 shows the FAT inside a reversible disk.
and the structure of the directory area, as is clear from this figure (FAT2a.

It can be seen that the directory area 2b and the directory area 3a are each composed of a plurality of sectors4.For example, in this figure, the FAT1i area has three sectors (first sector to third sector).
, the directory area consists of four sectors (first sector to fourth sector). In this case, the 'FAT area handles important file chain information, so in order to increase reliability, the same content is written twice (the first FAT (2a) and the second FAT (2b) exist). In the description, each sector of the FAT or directory may be referred to as a FAT first sector or a FAT second sector.

By the way, the range of applications of write-once optical discs is expanding due to their large capacity and ease of operation.These write-once optical discs store data in units of predetermined sectors and blocks, for example, from the inner circumference to the outer circumference. Record.

(Issues that the invention aims to solve!) However, because write-once optical discs have been developed for a short period of time, the data recording format is not necessarily standardized, and some manufacturers use their own unique file formats. The current situation is that a management method is being adopted.

If you try to manage this write-once optical disk using the same management method as the flexible disk, the area other than the file area (for example, the directory area) will be
This is predetermined by the following rules, and files cannot be managed on non-erasable write-once optical discs because they cannot be rewritten.

For example, the directory area 3.3a becomes full once. That is, the conventional O8 cannot handle this, and therefore, even if there is an unrecorded area in the file area 4, the unnecessary directory area 3.3a cannot be erased, making it impossible to write any more files in the file area 4.

The present invention has been made in view of the above-mentioned points, and has the following features: (1) to efficiently utilize the file area of a disk-shaped recording medium other than a flexible disk including a write-once optical disk, and (2) to make a write-once optical disk transparent for general-purpose O8. The purpose is to provide a disk data management method for data management.

(Means for Solving the Problems) The present invention uses write-once media to allow a general-purpose operating system to manage disk data in the same way as reversible media. This invention provides a disk data management method characterized in that a predetermined area is updated only once at the time of file registration.

(Example) Fig. 1 is a schematic diagram showing the area allocation of a write-once disk obtained by this method, and Fig. 2 is a schematic diagram showing the allocation of areas of a conventional disk and a write-once disk obtained by this method. This is a schematic diagram showing the correspondence of later disk areas.This is a schematic diagram showing how to write once on a write-once type of media, so that a general-purpose OS can perform the same file management as reversible media. This was achieved by ensuring that

Note that, in the present invention, reading/writing of data on a disk is performed in units of a fixed length called a sector, as is conventional.

In FIGS. 1 and 2, the FATIO and directory areas 11 are areas that are additionally updated each time a file is read/written, as described above.

In order to accommodate write-once media, the present invention continuously and fixedly secures sufficient capacity to rewrite these areas in adjacent areas of the disk.

Each region will be explained below using FIGS. 1 and 2. First, the explanation will begin with the directory area 11, which is the gist of the present invention in allocating the entire area of the medium.

The directory area 11 is an area for storing file names, and an area is reserved so that data can be added and updated by a fixed length (32 bytes) each time one file is registered, and can be rewritten for the number of managed files. Therefore, the number of rewrites until the first sector of the directory becomes full is (1 sector length/32 bytes). Therefore, an area for (number of rewrites of one directory sector x number of directory sectors) sectors is taken on the disk, and this is made to correspond to each sector in the conventional system. However, when actually registering a file from the general-purpose O8, the directory area is written twice, once when the file is opened and when the file is closed. If this writing is performed sequentially, a rewriting area of two sectors is required for each file creation, and a huge amount of spare area is required.

(See Figure 3) Therefore, in the method of the present invention, D
The intended purpose was achieved by controlling writing in the IR area. That is, when registering one file from the general-purpose O8, the process is executed according to the following procedure.

Read the FAT area - Read the DIR area → Write the DIR area (14rite) → Write the file area → Write the FAT area - Write the last sector of the file area → Write the DIR area When the first file is opened When writing to the DIR area, the file name and file creation date and time information are stored in the area on the disk, and when writing to the DIR area when closing, the total capacity of the file is added and updated.

Therefore, the final data to be left on the disk is the IR.
Only the content is sufficient, and DIR1i is required between the first and second time.
Since the DIR area is not referenced, it is not necessarily necessary to record the first information (see Figure 4).Therefore, as shown in Figure 5, the DIR information is written to the disk only when closing. Controlled using flags. In other words, FAT■, DIR■, ■, FI as a logical sector determination unit.
Set four areas L and E■, and as area ■, FAT → FILE flag = 1 as area ■, DIR and FILE flag = φ-*Write
= 0 (writing omitted) → FILE flag = φ (FILE flag reset) As area ■, DIR and FILE flag = 1-
Write = 1 (Write) → FILE flag; φ (FILE flag reset) FILE flag = 1 for area ■. As a result, the area reserved as a DIR area on the disk is halved, making it possible to effectively utilize disk space.

Note that a blank sector portion 13 corresponding to, for example, five tracks of the disk is provided between the directory area 11 and the file area 12. This is provided to shorten the time required to detect the boundary between the directory area 11 and file area 12.

Next, the FAT area 10 will be explained with reference to FIGS. 1 and 2. FAT is an area for storing chain information of data storage blocks, and the amount of information increases in variable length according to the size (capacity) of write data. Therefore,
The maximum number of times the first sector of FAT can be rewritten is determined by assuming that the data capacity of all files is within one block, and by setting the FAT data to 12 bits (1 sector length/1 block).
2 bits) times. On the disk, a blank sector portion 13 for each sector in the conventional system is required for the maximum number of rewrites plus five tracks. Blank sector part 1
The purpose of 3 is the same as that of the directory area 11.

On the other hand, if the FAT is updated once every time one file is registered, the number of times the entire FAT area is rewritten will be equal to the number of files that the O8 can manage.

Therefore, the minimum number of sectors required for the entire FAT area is (number of registrable files)+(blank sectors)Xn.

According to this method, in order to minimize the capacity of the entire FAT area, the starting address of each of the second to nth FAT sectors is not fixed, but the following method is adopted.

In other words, since FAT data is added to a variable length with a single update, it is not known how many times the amount of information in one sector will be exceeded and recorded in the second sector of the FAT. When the amount of information in one sector exceeds the length of one sector and subsequent data is recorded from the second FAT sector onward, the number of sectors for five tracks is added to the final address of the FAT first sector. The value is FAT
Register as the start address of the second sector.

In this way, the undefined number of rewrites for each FAT sector is absorbed by freely moving the start address of the next FAT sector within the FAT area 10.

Next, with reference to FIGS. 6 and 7, an example will be described in which the entire area of the FAT and directory is updated sector by sector, and the final information of each constituent sector is added to refer to the entire area. Here, Fig. 6 is a schematic diagram showing a method for updating the FAT area, Fig. 7 is a schematic diagram showing a method for updating a directory area, and Fig. 8 is a diagram showing R (read)/W (write) control for a write-once optical disc. be.

As mentioned above, R/W (read/write) of data on the disk
Writes are performed using a fixed length unit called a sector, and the FAT and DIR areas each consist of a plurality of sectors.

Updating FAT and DIR information is done by recording the combination of previous information and newly added information in sector units to the new sector next to the already recorded area of FAT and DIR.The amount of information is 1 sector. If the amount exceeds the number, a new fixed address is created with the excess amount as the second sector, and the addresses below that address are written sequentially.The addresses that contain the latest information of each sector that makes up the FAT, etc. are indicated by the pointer in Figure 9. It is managed by the department.

Pointers are prepared for the number of sectors that make up the FAT. The first fixed address to be set is the first FAT area 10a.
, and the second FAT area 10b, only the first sector start address and the remaining pointers are initialized to φ. Light (Wri)
te) At times, information is recorded in the new sector following the already recorded sector, and the contents of this pointer (sector address of the latest information)
Increase by one.

The information to be written exceeds the FAT first sector and is written to the FAT second sector.
When additional recording is to be made to a sector, add the value obtained by adding the number of sectors for 5 tracks to the latest address of the FAT first sector.
Register it in the pointer section as the start address of the second sector. Here, blank sectors for five tracks are inserted at sector boundaries in order to shorten the time for detecting sector breaks. Furthermore, when reading data, the actual address of the latest sector is read by referring to the pointer of each sector.

However, when the content of the pointer is φ, no writing has actually been performed on that sector, so the initialization information for that sector in the FAT is transferred to the system side. This is done so that unnecessary initialization information does not need to be recorded on the disk. Furthermore, since the start address of each sector is not fixed but can be made flexible, the overall capacity of the FAT area can be significantly reduced.

This point will be explained below using FIG. 9.

Figure 9 shows read/write (44rite)
) is a block diagram illustrating pointer management at the time.

Here, the process when the FAT unit 10 is started up has been described above, so its explanation will be omitted.

(1) First, reading from the FAT section 10 will be explained.

In the FAT section, the logical sector address is read from the pointer for each sector.6 Next, the pointer is referenced, and if the pointer is φ (the logical sector address is φ), that is, no data has been written, the system The initialization information is transferred to

In this case, data that has not actually been written is transferred to the system side (data requesting side) as if it were read from an optical disk.

(Secondly, in the above, if the pointer is other than φ, data on the optical disk is read. That is,
When the content of the pointer is other than φ, data is stored on the optical disk, and the pointer points to its logical address.

Then, this logical address is converted into a physical address before data is read.

(Thirdly, the write operation of the FAT section 10 will be explained.

In the FAT section, a logical sector address is written using a pointer for each sector.The pointer is referenced, and if the pointer is φ, a new write address is set. In other words, the pointer at the time of writing is φ,
This is the first time to write to that sector,
In that case, the logical sector address is calculated by referring to the first address of the previous sector (for example, in the case of the FAT second sector, the final address of the FAT first sector is referred to).

The data is written into the pointer section using the address plus the number of blank sectors for 5 tracks as the starting address.

(4) Next, in the above case, if the pointer is other than φ, the contents of the pointer are updated. In other words, if the contents of the pointer are other than φ, it means that writing has been done so far, so the new area is Update the contents of the pointer at the same time as writing the data.

Next, a method for updating the directory area 11 will be explained with reference to FIG.

The method of updating the directory area is basically the same as FAT, in which information to be newly stored is added to the existing information and recorded in a new sector next to the already recorded sector in sector units. Similarly, the amount of information exceeding one sector is recorded as the second sector, and a pointer is provided for each sector, and the latest information address of each sector is managed by the pointer shown in FIG. 8 above. However, unlike FAT, the directory is 1
Since the information updated per time is fixed at 32 bytes, the number of times each sector is updated is determined by the sector length. That is,
(1 sector length/32 bytes) times. Therefore, in the directory area, if the start address of the first sector of the directory is set, the start addresses up to the m-th address can naturally be determined. Therefore, there is no need to insert a blank sector for detecting the start address of the next directory sector at each sector boundary unlike in the FAT area, and the disk space can be used effectively. However, a blank sector 13 is inserted at the boundary between the directory area and the file area for boundary detection.

When data is written (14write), the contents of the pointer are incremented by one and new information is written to the next sector.

Read > Sometimes, the contents of the latest directory information sector are read by referring to the contents of each pointer. When the contents of the pointer are φ, no writing has actually been done to that sector, so
The directory initialization information is transferred to the system side.

This eliminates the need to record extra initialization information on the disk and increases the efficiency of detecting the start address of each sector.

(Effect of the invention) According to the present invention as described above, when one file is registered, one
By simply updating a predetermined area (DIR area) once, write-once disks can be placed under the control of general-purpose O8 in the same way as conventional media such as floppy disks and hard disks. and system calls (software interrupts), the management of files in the device can be left to O8, and various software that runs on general-purpose O8 can be run on write-once disks. Manufacturer)
Even if a device is newly created, it has the advantage of providing versatility by placing it under the management of O8.

[Brief explanation of the drawing]

Figure 1 is a schematic diagram showing the area allocation of the write-once disk obtained using this method, and Figure 2 is the correspondence between the disk areas after allocation of the conventional disk and the write-once disk obtained using this method. FIG. 3 is a schematic diagram of the DIR area when write control is not performed, FIG. 4 is a schematic diagram of the DIR area when write control is performed, and FIG. 5 is a schematic diagram of the DIR area when write control is performed. A block diagram showing the setting of flags, Figure 6 shows the FAT on a write-once disk obtained using this method.
FIG. 7 is a schematic diagram showing how to update the DIR area, FIG. 8 is a read/write control diagram for a write-once optical disc, and FIG. 9 is a block diagram showing pointer management during read/write. 10 is a schematic diagram showing the internal structure of a conventional block device, and FIG. 11 is a schematic diagram showing the internal structure of a conventional disk. 9 10...FAT area, 11...DIR area, 12・
...File area, 13...Blank sector part. Patent applicant: Japan Victor Co., Ltd. Representative: Kunio Kakimoto

Claims (1)

[Claims] In order to use write-once media and have a general-purpose operating system manage disk data in the same way as reversible media, write in unnecessary parts and update a specified area only once when registering one file. A disk data management method characterized by: