JPH047630A - Storage medium accessing method - Google Patents

Abstract

PURPOSE:To shorten access time by accessing plural unit areas at a time based on one referred result of a file control table when the physical addresses of plural unit areas to be accessed continuously are consecutive to each other. CONSTITUTION:Before the execution of access to a storage medium, it is decided whether the unit areas to be executed are physically consecutive on the storage medium or not. As the result, plural unit areas decided to be physically consecutive are accessed at a time as considering each unit area to be the area of one mass. Thus, since the access is executed extending over plural unit areas, the calculation of the physical position of each unit area need not be executed for every unit area.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a storage medium access method relating to a storage medium provided with a plurality of unit areas each storing one unit of data block.

(Prior Art) In computer systems, various storage media are used as media for storing data. Examples of commonly used storage media include floppy disks and hard disks. In order to use the storage areas of these storage media efficiently, they are divided into a plurality of unit areas each having a predetermined storage capacity.

Data stored on the storage medium is stored keeping this unit area in mind. That is, the data of the - group is divided into one data block corresponding to the capacity of the unit area and stored. In this way, since data blocks are stored in each unit area, there is an advantage that, for example, it is not necessary to physically secure a continuous area on the storage medium for storing the -group data. That is, there is an advantage that it is sufficient to secure the necessary number of unit areas, and these unit areas do not necessarily have to be physically continuous.

FIG. 2 shows a configuration diagram of a general computer system.

As shown in the figure, a file control board (PCB) 3 and a main memory (MEM) 4 are connected to the CPU 1 via a path line 2.

The CPU 1 controls each part constituting the system and performs various calculation processes. The path line 2 is a signal line for transferring data between the various parts constituting the system. The PCB 3 is an interface that executes access (reading and writing) control of the storage medium, in this case the floppy disk 5. MEM4 is a CPU
It consists of a RAM, etc. that stores programs and data referenced by I.

Now, before the floppy disk 5 is used, it is formatted, and its storage area is divided into predetermined unit areas (record generation).

- When storing the group data on the floppy disk 5,
The data is divided into a plurality of data blocks matching the capacity of this unit area. Further, in order to manage the usage status of each record on the floppy disk 5, a management table is provided on the MEM 4.

Access to the floppy disk 5 is performed by the CPU 1 issuing an access instruction (consisting of types of read control and write control, file name, etc.) to the PCB 3. That is, the CPU 1 entrusts access control of the floppy disk 5 to the PCB 3. Specifically, when the CPU 1 accesses the floppy disk 5, the CPU 1
PCB3 issues an instruction to B3. PCB3 analyzes this instruction and, for example, in the case of write control, refers to the management table on MEM4, secures a vacant unit area record, and stores a group of data in this secured unit area. Stores data blocks based on In the case of read control, refer to the management table on the same MEM4 to understand the unit area in which each data block that makes up a group of data is stored, and read the data blocks from each unit area sequentially to create a group of data. generate.

FIG. 3 shows a conceptual diagram of access.

The figure shows a floppy disk 5 and a management table 10 provided on the MEM 4.

The floppy disk 5 has the first to seventh areas 68 to 6g.
It is assumed that a file area 6 consisting of seven unit areas is provided. The management table 10 is also provided with seven items, first to seventh items 10a to 10g, corresponding to each of these areas.

The first to seventh areas 68 to 6g are areas for storing one data block of a predetermined amount (one unit). Management table 1
0 is provided in one-to-one correspondence with each area on the floppy disk 5, and stores the usage status of each area and an identifier for maintaining continuity with other areas.

Now, the second and sixth areas 6b of the floppy disk 5,
It is assumed that 6f stores independent data blocks, that is, data blocks A and B that are unrelated to each other. For this reason, the second and sixth items 10b and lof of the management table 10 each store an END identifier (for example, content "FFF+s") indicating that consecutive items do not exist on the management table 10.

On the other hand, a first data block, a second to fourth data block, and a fifth data block are stored in the first area 6a, third to fifth areas 60 to 6e, and seventh area 6g, respectively.

These five data blocks are the first data block ~
By arranging the data in the order of the fifth data block, - group data 7 is generated. Therefore, when reading these data blocks, it is necessary to read the first data block first and the fifth data block last.

Therefore, each item in the management table 10 stores an identifier that specifies the item corresponding to the area to be read next. That is, the first item 10a has a third identifier indicating the third item 10c, and the third item 10c has the fourth item d.
Similarly, the fourth item 10d and the fifth item 10e store fifth and seventh identifiers, respectively. Note that since there is no subsequent item in the seventh item Log, an END identifier indicating that it is the last item regarding data of the - group is stored.

Now, in the above configuration, the case where the first to fifth data blocks are accessed (for example, read) will be explained with reference to FIG. 4.

FIG. 4 is a flowchart of a conventional access method.

First, upon receiving an access instruction from the CPU 1, the FCB 3 determines the data block to be accessed from the instructed file name (step Sl). Specifically, the first item 10a corresponding to the area to be accessed first can be grasped based on the file name, and this first item 1
The track number, side number, and physical sector number on the floppy disk 5 corresponding to 0a are determined. That is, the first
Region 6a is identified. Then, the data length to be accessed in -degrees (parameter indicating the data length for - unit area)
are determined (step S2), and the floppy disk 5 is accessed based on these determined matters (step S3). When the access is completed, the FCB 3 determines whether the content of the first item 10a is an END identifier, that is, whether the access process is finished (step S4).

Here, the result is NO, and the process returns to step S1 again.

Finally, when the fifth data block is read from the seventh area 6g, the contents of the seventh item 10g are set to EN in the FCB3.
It recognizes that it is a D identifier and ends the read process.

Note that each read data block is sequentially transferred onto the MEM 4, and finally a group of data 7 is generated.

(Problem to be Solved by the Invention) The storage medium access method described above involves a process (step SL), and processes such as seek for specifying a desired area on the floppy disk 5 are executed. In this way, data access involves mechanical processing that is not directly involved, creating a problem in that it is difficult to complete access quickly. Additionally, when attempting to complete access in a shorter time, there was a problem in that high-performance hardware with short seek times, etc. had to be prepared.

The present invention has been made with attention to the above points, and an object of the present invention is to provide a storage medium access method that can easily shorten access time without preparing special hardware. .

(Means for Solving the Problems) A storage medium access method of the present invention comprises: a plurality of unit areas formed on a storage medium for storing one unit of data block each; and a management table associating the unit area with an identifier for specifying the other unit area to be accessed next, and accessing each unit area by referring to the management table, wherein the management table As a result of referring to the file management table, if the physical addresses of multiple unit areas that should be accessed consecutively are mutually consecutive, the multiple unit areas can be accessed at once with one reference result of the file management table. It is something to do.

(Operation) In this method, before accessing the storage medium, it is determined whether the unit areas to be executed are physically continuous on the storage medium. As a result, for a plurality of unit areas that are determined to be physically continuous, each unit area is accessed at one time as one area. In this case, since access is performed across a plurality of unit areas, there is no need to calculate the physical position of each unit area.

(Embodiment) The present invention can be realized in the computer system described above with reference to FIG. 2, and the management of the floppy disk 5 is performed using the management table 10 as in the conventional art.

Therefore, FIG. 1 according to the present invention will be explained here with reference to FIGS. 2 and 3.

FIG. 1 is a flowchart of the storage medium access method of the present invention.

Before going into the explanation of FIG. 1, the present invention will be explained in detail.
It is determined whether the unit areas on the floppy disk 5 to be accessed are physically continuous or not, that is, whether the contents of the identifiers stored in each item of the management table 10 are continuous. If the result is that they are not consecutive, each area of the floppy disk 5 is accessed one by one as in the conventional case.

On the other hand, if they are continuous, multiple areas are accessed at once. That is, normally, for example, 1 is accessed in byte units, but 2 is accessed in byte units, and 3 is accessed in byte units.

Now, let's get into the specifics.

In FIG. 1, step Sll and step S12 are
This process is the same as steps Sl and S2 previously explained in FIG. 4. In step S13, the item on the management table lo corresponding to the previously determined data block (
In this case, the content of the first item 10a) is analyzed to determine the item corresponding to the area to be accessed next (step S13), and as a result, the third item 10c is determined,
The corresponding third area 6c is determined to be the next data block to be accessed. And FCB3
determines whether the newly grasped item (third item 10c) and the previously grasped item (first item 10a) are physically consecutive items on the management table 10 (step 514). ). For example, in the case of the first item 10a, the physically continuous item refers to only the second item 10b. Regarding this second item 10b,
They are the first item 10a and the third item 10c.

In this case, the result of step S4 is NO, and the process moves to step S15. In step S15, it is determined whether or not the data block grasped in step 313 is the final data block, that is, whether the contents of the items on the management table 10 are EN or not.
It is determined whether or not it is a D identifier. Here, the result is NO (because the content of the third item 10c is the fourth identifier), and the FCB 3 executes intermediate access to access only the first area 6a (step 516), and returns to step S12. In step S12, parameters are set, and in step S13, the fourth item 10c is set based on the content of the third item 10c, that is, the fourth identifier.
d is grasped (step 514), and the process moves to step S15. The result in step S15 is YES, and the process moves to step S17. In step S17, step S1
5. Similarly, it is determined whether or not the final data block has been determined. In this case, the result is NO, and the parameter is changed, that is, the same content as the parameter previously set in step S12 is added, and the process proceeds to step S13. return. Thereafter, step S13. S14. S17. A loop such as S18 is executed up to the fifth item 10e of the management table 10. Then, in step S13, the seventh area 6g corresponding to the seventh item 10g is grasped. Here step S1
The result of step S15 is NOl and the result of step S15 is YES.
becomes. Then step S19 is executed. In this step S19, three blocks, the second data block to the fourth data block in the third area 60 to the fifth area 6e, are accessed at once. That is, the first area to start accessing is the third area 6c, and data (for example, 3 bytes) according to the parameters corresponding to the three data blocks is accessed. Thereafter, parameters (for example, 1 byte) are determined for the data block finally determined in step S13 (step 520), and its access (seventh area 6g) is executed (step 521).
Finish the process. Note that, for example, if the fourth data block in the fifth area 6e is the final data block, YES is determined in step S17 after step S14, and the third data block to the second data block in the fifth area 6e is
The fourth data block is accessed continuously (step 522), and the process ends.

By the way, when performing write processing, management table 1
0 will be referenced to search for an empty item, but
By determining whether or not the items indicating vacant contents are consecutive, it is possible to implement the same process using the same procedure as that described above using the write process as an example.

As described above, a plurality of data blocks physically consecutively stored on the floppy disk 5 are accessed at one time. This eliminates the need to spend mechanical processing time such as seeking each time each block is accessed.

The present invention is not limited to the above embodiments.

In the embodiment, a floppy disk is used as an example of a storage medium, but this is not particularly limited, and storage media such as hard disks that have a storage area divided into fixed areas and each storage area is managed by a management table. As long as it is, it doesn't matter what it is.

(Effects of the Invention) According to the storage medium access method described above, multiple unit areas on the storage medium can be accessed at once, so that -
Access to a plurality of data blocks corresponding to a group of data can be quickly completed.

[Brief explanation of drawings]

FIG. 1 is a flowchart of the storage medium access method of the present invention, FIG. 2 is a configuration diagram of a general computer system, FIG. 3 is a conceptual diagram of access, and FIG. 4 is a flowchart of a conventional access method. 1... CPU, 2... Pass line, 3... File control board (PCB), 4... Main storage device (MEM), 5... Floppy disk. - Configuration diagram of the boat computer system Fig. 2 Flowchart of conventional access method Fig. 4

Claims (1)

[Scope of Claims] A plurality of unit areas each formed on a storage medium to store one unit of data block, each of the unit areas, and the other unit area to be accessed next to any of the unit areas. In a device that is provided with a management table that associates identifiers that specify unit areas, and accesses each unit area by referring to the management table, as a result of referring to the management table, it is determined that subsequent accesses should be made continuously. If the physical addresses of multiple unit areas are consecutive, one reference result of the file management table can be used to convert the multiple unit areas into one.
A storage medium access method characterized by accessing the storage medium at once.