JPS6097443A - Control system of mass storage system - Google Patents

Abstract

PURPOSE:To operate independently an access mechanism by merely specifying a virtual access means and generating an access instruction by a host computer, and selecting an optimum physical access means by a controller in a mass storage system, and making the result correspond to the specified virtual access means. CONSTITUTION:Each host computer CPU when waiting for an access request sends an instruction for moving a data cartridge to a virtual access control mechanism and access mechanism ARC/ACC through a primary controller DIR0. Once this instruction is received, such a physical access mechanism that a processing time is shortest is selected according to the address of the cell containing the data cartridge, the address of a data recording mechanism DR which performs recording and reproduction, and the operation performance of current physical access mechanism to perform access. One primary controller DIR0 performs batch control over two physical access mechanisms ACC0 and ACC1 individually to make the best selection.

Description

[Detailed Description of the Invention] [Technical Field of the Invention] The present invention relates to a control method for a mass storage system such as a so-called MSS, and in particular to a method for preventing collisions between access mechanisms in a system equipped with a plurality of access mechanisms. This invention relates to a control method for efficiently operating each access mechanism.

[Technology background]

A large-capacity storage system is an auxiliary storage system that uses a large number of cartridge-type magnetic tapes and has an automatic storage function for magnetic tapes, and aims to increase capacity, save labor, and increase speed based on the concept of virtual DASD. It is.

FIG. 1 is a block diagram illustrating the configuration of a conventional mass storage system in a simplified manner for convenience, where 1 is a cartridge storage mechanism and 2 is an access control mechanism.

3 and 4 are access mechanism (ACC), δ and 6 are data recording mechanism (DRD), '7 is data recording control mechanism,
8 is a staging disk control device, 9 and 10 are staging disks (SD), and 9α is a control data server)
, 11 is a mass storage control mechanism.

12 and 13 indicate host computers.

To briefly explain the operating function, access mechanism 3゜4 is 1
It is movably mounted on the book rail, and captures the designated data cartridges according to commands from the access control mechanism 2, and stores them in cells (not shown) in the cartridge storage mechanism 1 and the data recording mechanism ( DRD) 5 or 6, etc.

A data recording device (DRD) 5.6 records data on or reproduces data from magnetic tape in a mounted data cartridge. The data recording control mechanism 7 controls the data recording mechanism 5.6 and performs data modulation/demodulation, error detection and correction, and the like.

The staging disk control device 8 transfers the data in the data cartridge to a staging disk (9 or IO
), and controls data transfer in response to read/write access requests to the virtual DASD from the host computer 12.13.

The mass storage control mechanism 11 controls the entire system via the access control mechanism 2 and the staging disk control device 8 in accordance with instructions from the host computer.

The mass storage control mechanism 11 manages the usage status of the access control mechanism (ABC) using the mass storage system control data set stored in the DASD 9.10, for example 9af, and requests access to the virtual DASD. When a data cartridge is found, a usable data recording mechanism is selected by referring to this control data set, and an instruction to move the data cartridge is issued to the access control mechanism.

The access control mechanism decodes the given move command and instructs the access mechanism 3''& or 4 to perform necessary control operations so that the operation time is minimized.

However, in such cases, conventionally, one access control mechanism controls two access mechanisms, so only one cartridge can be transported in one operation (two cartridges cannot be transported at the same time). In addition, there was a drawback that a large and bulky device was required as an access control mechanism to prevent collisions.

[Object and structure of the invention]

The object of the present invention is to provide a 9-large answer storage system.

It is useful to efficiently operate multiple access means and shorten access time (Fig. 1) and to simplify the configuration 1 mechanism. Therefore, the optimal selection control of the access means is dynamically performed by the mass storage system, The host computer simply specifies a virtual access method and issues an access command, and the control device in the mass storage system selects the most suitable physical access method based on the current control state and associates it with the specified virtual access method. Do it like this. This allows the two access mechanisms to operate independently.

Accordingly, the configuration of the present invention includes a storage shelf means in which a plurality of recording media are stored, a recording and reproducing means, and a plurality of access means for transporting the recording medium between the storage shelf means and the recording and reproducing means. , a plurality of access control means that control the operation of each access means, and a plurality of control devices that control the plurality of access control means and the recording/reproducing means according to instructions from a host computer. In a mass storage system, a virtual access control mechanism and an optimal control mechanism are provided, and a designated one of the plurality of control devices is provided with a virtual access control mechanism and an optimal control mechanism.
One control device oversees all access control means in the system, selects the optimal physical access means in response to access commands issued from the host computer to the virtual access means, and selects the most suitable physical access means for the access control means. It is characterized by optimal control.

[Embodiments of the invention]

The details of the present invention will be explained below based on examples.

FIG. 2 is a block diagram of one embodiment of the present invention.

In the figure, 15 is a rail. Reference numerals 16 and 17 are access mechanisms, represented as ACCG and ACCl, respectively. 1 and 19 are access control mechanisms, represented by A RCo and A RCz, respectively.

20 and 21 are control devices, respectively DIRO,
It is expressed as DIRI. 22 to 25 are host computers, respectively CPUo, CPU1゜CPtb,
It is expressed as CPU3.

The access mechanisms ACCo and ACCI are mounted on one rail 15 and are movable left and right. As shown in Figure 1, each ACCO and ACCI includes a stand, a carriage that can move vertically and rotate along the stand, and a data cartridge capturing head mounted on the carriage. ACCo and ACCl have their operations controlled by access control mechanisms ARCo and ARCI, respectively, and independently take out a data cartridge from a cell at an arbitrary position (not shown) or store it at that position, as will be further described later. The data cartridge is transported between the data recording mechanism (DRD) and the cartridge access station (CAS). Cartridge access station y (CA
S) is a window mechanism that takes data cartridges in and out of the system.

The access control mechanisms A RCo and A RCx respectively control the access mechanisms ACCo and ACCz, perform recovery processing from their operation errors, perform control 2 interrupt processing for the cartridge access station (CAS), and create sense bytes.

The control devices DIRO and DIRI perform command, message processing, and error recovery processing with each CPU.

It operates ARC/ACC, DRD, and data cartridges, manages statistical information regarding malfunctions, modulates and demodulates data, and performs error correction processing.

Host computer CP [JO, CPUI, CPU, +,
CPU3 is a control device DI Ro and DI, respectively.
Connected to both Rz. Control devices DIRO and DI
One of R1 (DIRo in the illustrated example) is designated as the primary control device, and handles commands such as moves (referred to as ABC commands) to the access mechanisms ACCo and ACCl in an integrated manner. However, for commands such as read/write to DRD (referred to as DRD commands), the above-mentioned restrictions are not set between DIRs.
Each control device DIRo, DIRz.

Necessary control regarding the above-mentioned commands can be performed for any data recording device (DRD).

Also, host computer CPU0. CPUI, CPU2.
Any one of the CPUs 5 (CPU0 in the illustrated example) is designated as the primary host computer, and only this computer CPUo has the ability to designate or change the designation as the primary control device.

When each host computer has an access request to data in a data cartridge, it first issues a command to move the data cartridge to the virtual ARC/ACC via the primary control unit DIRo.

The primary controller DIRo uses this virtual ABC/AC
When a move command for C is received, the address of the cell where the data cartridge is stored, that is, the storage shelf, and
A physical access mechanism with the shortest processing time is selected and executed according to the operating state of the data recording mechanism that performs recording and reproduction.

One primary control device DI Ro independently controls two physical access mechanisms ACCO for any virtual access mechanism instructed by the host computer.

By collectively controlling the ACC1 and selecting the most suitable physical access mechanism, efficient access to the data cartridge can be realized. Furthermore, it is possible to control mutual access mechanisms; it is also possible to predict a collision situation in which one access mechanism interferes with the operation of another access mechanism, and select an access mechanism that can avoid the collision; It becomes possible to perform an evacuation operation.

The number of virtual access mechanisms that can be specified from the host computer is
Consistent with the number of physical access mechanisms, ACCo and ACCl, the primary controller can always accept two move instructions, regardless of the virtual address mechanism address specified. Therefore, if another move command is issued while two move commands are being executed, it is reported to the nine issuing host computers that the device is in use.

When even one ACC becomes free, a release while in use is reported.

If a failure occurs in the primary control device D I Ro or the path from it, the primary control device D
I decided to switch from IRo to DIRl.

System operation can continue and reliability can be improved.

FIG. 3 is an explanatory diagram showing the control function of the primary control device.

When a move command is issued from one of the host computers, the ARC command reception routine 26 handles this and makes the optimization logic 27 functional.

The optimization logic 27 refers to the ABC management table 2 and selects the optimal access mechanism.

The ABC management table 28 includes information about each physical access mechanism ACC.
For each O, ACCI, whether it is in operation or not depends on the host being used), A
It holds information such as the operating range of the CC and whether or not it is being evacuated.

Address translation routine 28' maps the address to the address of a physical address mechanism if a virtual access mechanism is selected. On the other hand, if all physical accessors were in use.

The BUSY reporting routine 29 is caused to report that the shear device is in use.

The command processing routine 30 instructs the selected access mechanism to execute a move, and if a collision with another access mechanism is predicted, activates the evacuation routine 31 to perform the evacuation operation. . The save operation is performed while referring to the Ai'LC management routine, and when the save is in progress, it is recorded on the 2nd day of the ARC management table.

When the selected access mechanism completes the move operation, the interrupt is terminated by the interrupt processing routine 32.

FIG. 4 is a block diagram of another embodiment of the present invention.

Elements 16 to 19 in this figure are the same as those in the embodiment shown in FIG. 3, so their explanation will be omitted. Further, 34 is a cell (CEL), 35 is a cartridge access station (CAS), and 36 and 37 are data recording mechanism groups, respectively.

3rd to 41st are the control devices (DI Ro, D
I R1゜DIRa, DIR3).

In the embodiment shown in FIG. 4, four control devices (DIR) are coated with gold, one of which is designated as the primary control device. If a failure occurs in the designated primary control device, the designation is changed to one of the other three control devices, making the system even more reliable than the embodiment shown in FIG. @ Primary controller is ARCo /ACCo and AR
The point that both CI/ACCI are collectively controlled is the same as in the previous embodiment.

The data recording device (DRD) group 36 includes the control device D
The other data recording facilities (L)RL group 37 are managed by the control devices DIR2 and DIR3.

The cartridge access station (CAS) 35 is
It is connected to both access control mechanisms ARCo and ARCI, and interrupts related to data cartridge loading and unloading are reported to the host computer via both ARCs. In this way, since Nosos is duplicated, even if one ARC fails, system operation will not be affected.

〔Effect of the invention〕

As described above, according to the method of the present invention, control over multiple access mechanisms can be optimally controlled in accordance with actual conditions, and simultaneous transportation of multiple cartridges is also possible.
Accessor operating time is reduced on average, resulting in increased efficiency of the mass storage system.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of a conventional mass storage system. FIG. 2 is a block diagram of one embodiment of the system of the present invention, FIG. 3 is a control function diagram of the primary control device, and FIG. 4 is a block diagram of another embodiment of the system of the present invention. In the figure, 15 is a rail, 16 and 17 are access mechanisms,
18 and 19 are access control mechanisms. 20 and 21 represent control devices, and 22 to 25 represent host computers. Patent applicant Fujitsu Ltd. Representative Patent Attorney Fumihiro Hase (1 other person) Figure 1 Figure 2

Claims (1)

[Scope of Claim] Storage shelf means for storing a plurality of recording media. a recording and reproducing means; and a plurality of access means for transporting recording media between the storage shelf means and the recording and reproducing means. A large capacity device having a plurality of access control means that control the operation of each access means, and a plurality of control devices that control the plurality of access control means and recording/reproducing means according to instructions from a host computer. In a storage system, a designated one of the plurality of control devices is provided with a virtual access control mechanism and an optimal control mechanism. To unify all access control means in the system, select the most suitable physical access means in response to access commands issued from the host computer to the virtual access means, and perform optimal control over the access control means. A mass storage system control method featuring: