JPS61251928A - Compatible recording medium access system - Google Patents

Abstract

PURPOSE:To reduce the overwork of a host by interpreting information with a controller and replacing automatically a medium by a an automatic medium replacing device when only a logical block address and a logical block length are designated to access an optional data block. CONSTITUTION:When the host requests medium driving, a logical block address and a logical block length are calculated by an operator or a program designated method, and resultant information is sent to a controller 30 as instruction information. The controller 30 checks whether a logical block address range corresponding to the requested logical block address extends to two or more mediums or not by a conversion formula executing mechanism 32. If this range is mounted on one driving device 40 as the result, a physical address is calculated in accordance with the logical block address by the mechanism 32. If the range extends to two mediums, data buffers 34 and 35 are used to transfer data between these buffers and the designated address area of two mediums.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to an access method for a removable recording medium in a system consisting of a primary storage mechanism using a removable recording medium and a host processing device. be.

[Prior art]

Primary storage in current computer systems includes a control unit and seven or more drives connected to each other. Particularly when the recording medium is a removable medium, there is a primary storage mechanism that also includes an automatic medium changer. The control device receives commands from the host via the bus regarding the operation to be performed, the transfer start address on the medium, the transfer length, etc., converts this command information into the necessary signals and sends them to the appropriate drives and other systems. -Control data transfer between elements. The drive device operates the recording medium, reads data from the recording medium, transfers the data to the control device, and writes data transferred from the control device to the recording medium. The automatic media exchange device receives a command regarding media movement from a host or a control device, mounts a specified medium from a media storage position to a drive device, mounts a specified medium from the drive device to a media storage position, and also transfers a specified medium from the media storage location to another. Move the media to the media storage location.

Traditionally, for a host utilizing secondary storage to access desired data, it has been necessary for the host to be aware of the physical address structure of the medium.

Furthermore, even in systems that logically provide single-role addresses to users regardless of the physical hierarchy of the storage mechanism, the host must perform the conversion from single-role addresses to physical addresses. Therefore, the host had to know the physical address structure of the medium.

As an example of medium access, the case of a disk medium exchange type-next storage mechanism will be described below. The host first determines the medium number of the medium to be accessed by some method, and checks whether a medium having the medium number is mounted on any of the plurality of drive devices.

If the medium is not mounted on any of the drives, the controller or automatic medium exchange device checks the media storage location address storing the medium and mounts the medium from the media storage location on the drive. instruct. Thereafter, the control device or automatic media switching device notifies the host that the nuclear medium has been mounted, and upon receiving this notification, the host controls a seek command to move the recording/playback head of the drive device to the destination trunk of the medium. Output to the device. After the host receives notification of the completion of the seek from the control device, it outputs a search command to the control device to search for the target sector of the medium. After the host receives notification of the completion of the search from the control device, the host and the control device begin a data read or write operation.

[Problem that the invention seeks to solve]

As in the example above, in conventional systems, the host is required to manage complex procedures before accessing the actual data on the medium, and the host's O8 (O
The -next storage control routines in the perating system were complex. Therefore, when the physical specifications of the medium and the secondary storage mechanism are updated and the recording density of the medium is increased, etc., it is necessary to significantly change the host's secondary storage mechanism control routine.

Since the next storage control routine is then closely related to other processing routines, the changes to O8 are extensive and costly. Furthermore, the host had to frequently access the primary storage mechanism before actual data transfer, resulting in a significant drop in overall system performance.

[Means to solve the problem]

The present invention sets the address of a data block in a primary storage mechanism as a continuous logical block address across multiple media, and when the host accesses any data block between these addresses, it is specified by a logical block address and a logical block length. The control device interprets the information by simply
Based on the interpretation result, the automatic medium conversion device automatically exchanges the medium as necessary.The purpose is to reduce the overhead of the secondary storage control routine in the host, and to The object is to facilitate address conversion processing including conversion to a medium number.

〔Example〕

FIG. 1 is a diagram showing the configuration of an embodiment of the present invention, in which a four-coordinate storage mechanism 20 is connected to one or more hosts (not shown). 7 control devices 30, multiple drive devices 40°, 7 automatic medium exchange devices w
Including 50. The automatic media exchange device 50 includes a plurality of media storage locations [60]. control device [30 and automatic medium exchange device 50,
The control device 30[deg.] and the plurality of drive devices [40] are connected to each other in a known manner. The control device 30 includes a mount table 31, a logical block address to physical address conversion formula execution mechanism 32, a mount counter 33 that counts the number of required mounts, and one data buffer 34.
' and 35. The automatic medium exchange device 50 includes a storage table 51 and a conversion formula execution mechanism 52 for converting logical block addresses to medium numbers.

Figure 1 shows the structure of the above-mentioned tables.

FIG. 1(a) shows the configuration of the mount table 31, which includes drive device addresses of a plurality of drive devices 40, a mount identification flag for identifying whether or not a medium is mounted on the drive device 40, and a mount identification flag for identifying whether or not a medium is mounted on the drive device 40. The first logical block address assigned to the medium is stored.

Here, the first logical block address refers to the first block address of the logical block address range allocated to seven media. The mount identification flag stores, for example, O if the medium is not mounted, and 1 if it is mounted. FIG. 1(b) shows a storage table 51.
The configuration is shown, and the media storage location addresses of the plurality of media storage locations 60, a storage identification flag for identifying whether or not a medium is stored in the media storage location fff60, and the media number of the stored media are stored. has been done. The storage identification flag contains, for example, 101 when the medium is stored.
For example, 100 is stored when no medium is stored. However, if the medium is not stored at the moment and the drive unit
401c, the drive address is memorized when it is mounted.

The amount of physical continuous transfer between the host and the control device 30, ie, the amount of data transferred in temporally seamless transfer, is limited by the physical structure of the medium. However, typically a data buffer is used to temporarily store data in the data buffer so that the host and controller 30 can
The physical structure of the medium K is the amount of data continuously transferred between
However, it is possible to increase the number. Data buffers 34 and 35 in the present invention are also buffers for this purpose. Therefore, the capacity of the data buffers 34 and 35 only needs to be equal to the capacity of each normally used data buffer. For example, in the case of a disk medium, each has a capacity of one track or several sectors.

FIG. 3 shows the correspondence between logical block address ranges stored in each medium and medium numbers.

There are α logical blocks in seven media, and β media in the -th storage system. Although each medium is physically independent, logical block addresses are one-dimensionally continuous throughout each medium. Therefore, the host has a very large contiguous one-dimensional logical block address range, O~
It appears to be a primary storage mechanism with (αβ-1). The host does not need to know the medium on which the required logical block resides, or even the logical block address of a physical break in the medium, but only that there are αβ logical blocks across the storage structure. Good. Even if more than one medium is accessed at the same time due to the relationship between the logical block address and the amount of data to be transferred, the primary storage mechanism 20 automatically recognizes and controls this as described later, so the host can There is no need to be concerned with it.

The conversion formula from logical block address to physical address is:
For example, in the case of a disk medium that physically has tracks and sectors, the equation is as follows.

logical block address Number of logical blocks of force drawn on the track Number of tracks on media Also, the first logical block address is It is determined by medium number x number of logical blocks per medium.

Conversion formulas for other types of media will be readily deduced by those skilled in the art. The conversion formula execution mechanisms 32 and 52 are mechanisms that execute the above-mentioned conversion formulas.

Figure 2 shows normal medium access operations (for example, read and write operations) in the primary storage mechanism 20 shown in Figure 1.
The normal medium access operation in the primary storage mechanism 20 will be explained below with reference to the second figure.

If the host issues a media drive request, step 111
The logical block address and logical block length are calculated by a known method from the file name specified by the operator or the program. The calculated logical block address, logical block length, required operation, and other information are converted into command information, and the host sends the command information to the control bag [30] in step 112. The control device 30 is
In step 113, using the conversion formula execution mechanism 32, it is determined whether the logical block address range corresponding to the requested logical block address ~ (logical block address + logical block length) spans one or more media. investigate. First, the logical block address range is seven media Ki.
/3 will be explained below, and then the case will be explained where it spans one or more media.

The control bag [30 refers to the mount table 31 in step 114 to check whether the medium having the logical block address is mounted on any of the plurality of drive devices 40. If it is mounted on any one of the plurality of drive devices t40, the control device 30 calculates a physical address from the logical block address using the conversion formula execution mechanism 32 in step 115. The control device 30 converts the physical address, required operation, and other information into order information, and sends it to the drive device 40 mounting the medium corresponding to the logical block address range in step 116 to the host in step 117. Control the actions requested by.

As a result of the check in step 114, if the desired medium is not mounted on any of the plurality of drive devices 40, the control bag [30 sets 1 in the mount counter 33 in step 118, and displays LRU (Least Recent).
The drive device 40 to be mounted is selected in step 119 using a suitable known method such as the y' (Jsed) algorithm. The control bag [30] sends command information including the selected drive device address and the logical block address to a certain automatic medium replacement [50] in step 120. The automatic medium exchange device It50 is the drive bag to be mounted from the drive device address! 40, calculates the medium number from the logical block address using the conversion formula execution mechanism 52, and refers to the storage table 51 to determine whether a medium other than the medium to be mounted is mounted on the drive device 40. Step 12
Check with 1. If a medium other than the medium to be mounted is mounted on the drive device 40, the storage table 51 is referred to in step 122 to find out the storage position address where the medium should be stored, and the medium is demounted from the drive device 40. and store it in the storage position. Subsequently, or if no medium other than the medium to be mounted is found as a result of checking in step 121, the automatic medium exchange device 50 refers to the storage table 51 and selects the medium corresponding to the medium number to be mounted. Obtain the medium storage location 60 in which is stored. The automatic medium exchange device t50 performs step 12.
3, the medium is taken out from the medium storage position 60 where the medium is stored and mounted on the drive device 40, the drive bag [40 or the automatic medium exchange device 50 is removed in step 124.
The control device 30 is notified that the new medium has been mounted. In step 125, the control device 30 stores the corresponding start logical block address aVC of the medium in the mount table 31. Control bag [
30 counts down the mount counter 33 in step 126, and checks whether the mount counter 33 has reached 0 in step 127. In this case, the mount counter 33 is O, so the control bag [30 is at step 1]
Execute steps 15 to 117.

Next, the logical block address requested by the host ~(
A case will be described in which the logical block address range corresponding to (logical block address + logical prongs) spans one or more media. Once it is clear that the data spans one medium, the same operation can be performed even if the data spans three or more media, so in the following, we will explain how to straddle one medium. Let me explain the case. Continuity of transferred data in this case will be explained with reference to FIG. 5, which will be described later.

As a result of checking in step 113, if the number of desired media is one, the control device 30 determines that one medium is a plurality of drive devices [4].
Step 1:
The mount table 31 is checked at 28 and 129. If at least one of the media is mounted on any of the drives 40, the controller 30 performs steps 115-117.
Execute.

If, as determined in steps 128 and 129, any seven of the media are mounted on any of the drives 40, the control device [30 in steps 118-127 Execute. As a result of checking in steps 128 and 129, if none of the media is mounted on any of the drives 40, the controller fi! 1t30 sets the mount counter 33 to 2 in step 130, and then goes to steps 119 to 1.
Execute 27 once. After that, the control device 30 executes steps 115 to 117.

Figure 3 shows medium a with one logical block address range;
This is a data transfer sequence in the case of straddling b. 5(a) is a write sequence, and FIG. 3(bl is a read sequence).The data transfer unit that can be physically continuously transferred using the data buffers 34 and 35, that is, the capacity of each of the data buffers 34 and 35. For example, in the case of a disk medium, it is a track unit or several sector units.The amount of data transferred in seven write or read operations is pal-pam (medium a), Dbl~
Dbn (medium b), and assume that the last logical block address of Dam on medium a and the first logical block address of Dbl on medium A are consecutive.

First, the data transfer sequence of the write operation will be explained as shown in FIG. 3(a). In phase 1, 7Dal is transferred from the host to the control device 30, and the control device 30 stores a data buffer 34KDal. In phase 2, data Da2 is transferred from the host to the control device 30,
The control device 30 stores D&2 in the data buffer 35, and at the same time transfers 1)al stored in the data buffer 34 to the drive device 40 on which the medium a is mounted. The private device A writes Dal into the designated address area of the medium a. This data transfer sequence is sequentially repeated up to phase m. In phase m+1, the data transferred from the host to the control device 30 is Dbl, so the control device 30 stores Dbl in the data buffer storing Dam and another data buffer, in this example, the data buffer 34. At the same time, the drive device 4 mounting medium a
Transfer l)am stored in the data buffer 34 to 0.

The drive unit [40 drives D to the specified address area of medium a.
Write am. In phase m+2, data Db2 is transferred from the host to the control device 30, and the control device 30 stores Db2 in the data buffer 35 and at the same time transfers pbl stored in the data buffer 34 to the drive device 40 mounting the medium. The drive device 40 writes Dbl to the designated address area of the medium. This data transfer sequence is sequentially repeated up to phase m+n+1, and the data transfer sequence of the RY+ operation is completed.

Next, the data transfer sequence of the read operation will be explained according to FIG. S (b). In phase 1, the drive device 40 mounting medium a reads data Dal from a designated address area of medium a, and transfers [)al to control device #30. The control device 30 is the data buffer 3
Store Dal in 4.

In phase 2, at the same time that DILL is transferred from the data l buffer 34 of the control device 30 to the host, Da2 is read from the medium a by the drive device 40 and transferred to the control device [
Transferred to 30. The control device 30 stores Da2 in the data buffer 35. This data transfer sequence is sequentially repeated up to phase m. In phase m+1, the drive device (40) mounting the medium reads data BL from the specified address area of the medium and transfers DBL to the control device 30. The control device 30 stores Dbl in the data buffer storing pam and another data buffer, in this example, the data buffer 34, and at the same time transfers the pam from the data buffer 35 to the host. In phase m+2, at the same time that [ )bl is transferred from the data buffer 34 of the control device 30 to the host, Db2 is read from the medium by the drive device 40 and transferred to the control device [
Transferred to 30. The control device 30 stores I)b2 in the data buffer 35. This data transfer sequence is sequentially repeated up to phase m+n+1, and the data transfer sequence of the read operation is completed.

In this way, by using two data buffers, data access to a logical block address range across one medium can be smoothly executed from the host's perspective. Also, the operation of the primary storage mechanism for data access to a logical block address range that spans three or more media will be easily understood by this embodiment.

Note that the number of data buffers may be arbitrary depending on the design. In addition, seek orders and search orders from the control device 30 to the drive unit [40 that mounts the media] can be performed at appropriate timings depending on the unit of data transfer.

As described above, in this embodiment, the medium designation (step 120) in the medium mount request from the control device 30 to the automatic medium exchange device 50 may be a logical block address. Alternatively, the control device 30 may directly specify the medium to be demounted without storing the drive device address in the storage identification flag of the storage table 51. Further, although it has been described that the automatic medium exchange device [50] is equipped with the storage table 51 and the conversion formula execution mechanism 52, the automatic medium exchange device 50 is not equipped with them, and the control device 30 is equipped with the storage table 5.1'. ? :Equipped with
The control device 30 may directly specify the medium storage position of the medium to be demounted or mounted to the automatic medium conversion device 50. As described above, the format of the information and tables included in the command from the control device 30 to the automatic medium conversion bag [50] used here is merely an example, and may be arbitrarily designed according to the specific implementation method of the present invention. It's something you get. Furthermore, although this embodiment has described a primary storage mechanism having seven control devices and seven automatic medium conversion devices, a plurality of control devices,
A primary storage device 411 having a plurality of automatic medium exchange devices will also be easily understood by those skilled in the art based on this embodiment.

〔Effect of the invention〕

As explained above, when using the present invention, when accessing data to a data block address space spanning multiple media, the host does not need to specify the medium consciously, but only by specifying the logical block address and logical block length. Data access can be executed with . -t'', the host only needs to be involved in steps 111 and 112.

It is the primary storage mechanism that converts the information into physical addresses and performs the necessary operations (steps 113-130).

Even if the logical block address range accessed by the host spans one or more media, the host does not need to be aware of this, and data transfer is performed smoothly from the host's perspective. Therefore, data access by the host is facilitated, and the overhead of the secondary storage mechanism control routine in O8 is reduced. Also,
Since the logical block addresses of the media in the -next storage mechanism are consecutive, there is an advantage that address conversion processing including conversion to a medium number in the -next storage mechanism is facilitated.

Furthermore, there is also the advantage that the increase in the total cost of the system due to renewal of the -next memory mechanism is reduced. .

[Brief explanation of drawings]

FIG. 1 is a block diagram showing the configuration of an embodiment of the present invention, FIG. 2 is a configuration diagram of the tables shown in FIG. 1, FIG. 3 is a diagram showing the relationship between logical block address range and medium number, and FIG. The figure shows the normal medium access operation mode shown in FIG. 1, and FIG. 3 shows the data transfer sequence. 20...Next storage mechanism, 30...Control device, 40...Drive device, 50...Automatic medium exchange device, 60...・Media storage position, 31
．． 51...Table, 32°52...
Address conversion formula execution mechanism, 33... Young counter, 34.35... Data buffer. Figure 1 Nails Y△

Claims (2)

[Claims] (1) In an access method in which the removable recording medium in a secondary storage mechanism including a plurality of removable recording media, a control device, a drive device, and an automatic medium exchange device is accessed from an external host processing device, The address of the data block recorded on the removable recording medium is defined as a continuous logical block address, and the host processing device specifies an access address using the logical block address when accessing the data block on the removable recording medium. A removable recording medium access method characterized by: (2) The secondary storage mechanism includes an address storage means for storing a logical block address assigned to a replaceable recording medium mounted on the drive device, a means for converting the logical block address into a physical address, and a means for converting the logical block address into a physical address. The control device includes means for counting the number of times a medium is mounted on a drive device, and a means for temporarily accumulating data transferred from the host processing device or the drive device, and
The secondary storage mechanism includes means for storing a removable recording medium number stored in the secondary storage mechanism, and the removable recording medium corresponds to the logical block address specified by the host processing device. The control device uses the address storage means to determine whether or not the media is mounted on the drive device, and based on the determination result, the control device instructs the automatic medium exchange device to exchange the medium. 2. The removable recording medium access system according to claim 1, wherein the exchange device executes the medium exchange operation.