JPH0338716A - Peripheral controller - Google Patents

Abstract

PURPOSE:To enable a host device to carry on a due process with no consciousness of occurrence of a deck fault by changing the correspondence between the logical and physical addresses of the deck within a peripheral controller and moving a medium via an access means. CONSTITUTION:If a fault occurs at a deck #0, for example, a microprogram processing part 13 checks the deck state storage part 121 in a deck control table 12 to search such a deck that contains no medium loaded and is not occupied by a host device. If a deck having a logical address '7' is not used yet, a medium is taken out of a deck #0 having a physical address '0' and given to an access means 3. Then an instruction is produced to load the medium into a deck #7 of a physical address '0'. Furthermore, the correspondence is changed between the logical and physical addresses of an address conversion means 11. Thus, it seems to the host device as if a fault occurred at the deck of the logical address '7'. Then an input/output request is normally carried out as it is with a logical address '0'.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a peripheral control device, and in particular to a library-type peripheral equipped with a plurality of decks for recording and reproducing, cells for storing media, and accessors for moving media. The present invention relates to a peripheral control device that controls a device.

[Conventional technology]

Conventionally, this type of peripheral control device only reports the deck abnormality to the higher-level device if a problem occurs in the deck and the process is not completed normally while executing an operation instructed by the higher-level device. Ta. When this abnormality is reported, the host device must use the accessor to move the medium to another deck, reload it, reposition it for error recovery processing, and restart processing according to software instructions. there were.

Furthermore, in the case of a peripheral control unit that has a large-capacity buffer, and when a write command is issued, it reports the end of the command as soon as data is stored in the buffer, and writes to the medium asynchronously. In this case, the host device must collect the unwritten data in the buffer before moving the medium as described above, and for this purpose, it must secure a storage area, collect the data in the buffer, move the medium, and perform error recovery processing. repositioning,
The process is restarted after executing a series of processes such as writing collected unwritten data.

[Problem to be solved by the invention]

As described above, in the conventional peripheral control device, when a deck failure occurs, the host device must interrupt the process being executed and instruct the error recovery process.

In particular, in the case of a peripheral control device that has a large capacity buffer and writes data to a medium asynchronously in response to a write command from a host device, the host device must collect unwritten data in the buffer.

In this case, since the peripheral control unit has already reported completion in response to the write command from the higher-level device, the higher-level device must again secure a storage area to retrieve the data in the buffer. If the area cannot be secured, error recovery processing cannot be performed and processing must be interrupted.

[Means to solve the problem]

The peripheral control device of the present invention includes a plurality of decks for writing and reading data to and from a medium, cells for storing the medium,
In a peripheral control device that controls a library-type peripheral device having the cell and an accessor for moving media between decks and between decks, the physical address of each deck and an input/output request from a higher-level device are provided. address translation means that stores the correspondence with the logical address used at the time and can be arbitrarily changed; deck information management means, which includes a deck status storage unit that stores information such as whether or not a deck is present, and an error information storage unit that stores position information necessary for recovery processing when a deck failure occurs; When a failure occurs in a deck that is executing an instruction, the deck information management means is referred to to find an unused deck, move the medium of the deck where the failure has occurred, and instruct execution of recovery processing, and the address conversion and fault processing means for changing the memory of the corresponding deck portion of the means.

〔Example〕

Next, the present invention will be explained with reference to the drawings.

FIG. 1 is a block diagram showing an example of the configuration of a library type magnetic tape subsystem using the peripheral control device of the present invention.

The library-type magnetic tape device connected to the peripheral control device 1 has eight decks #0 to #7 that write and read data to and from media, a cell 2 that stores the media, and each deck #0 to #7. Accessor 3 for moving media between 7 and cell 2
It consists of 5-.

The peripheral control device 1 includes an address means 11 that converts a logical address of a deck into a physical address, a deck control table 12 that stores various control information corresponding to the logical address of each deck, and exchanges input/output commands with a host device. , an I that controls data transfer between the host device and the buffer 14, etc.
10 control unit 15 and a READ/W that performs data transfer control between decks #O to #7 and buffer 14, D/A conversion, etc.
RITE circuit 16 and multiple connected decks #0 to #
an interface circuit 17 that selects a deck having the physical address indicated by the address conversion means 11 from 7 and controls data transfer to and from the deck; a buffer 14 that stores write data or read data to the deck;
I10 control unit 15. It consists of a microprogram processing section 13 that instructs the operations of the peripheral control device 1, such as instructing the READ/WRITE circuit 16 to start data transfer. Note that the address conversion means 11 is stored here as a table of physical addresses 1120 corresponding to the logical addresses 111, as shown in FIG.

The deck control table 12 corresponding to the logical address of each deck stores information such as a deck status storage unit 121 indicating whether a medium is loaded on the deck, whether the deck is occupied by a host device, etc., and location information at the time of failure. An error information storage unit 122 is included. Address conversion means 1
Logical address 111 and physical address 1 in the initial state of 1
The correspondence of 12 is as shown in FIG. 2(a). Therefore, when the host device attempts to write to a medium loaded on deck #0 with logical address "0", the microprogram processing section 13
5 to start data transfer and transfer the data to buffer 1.
4, and when writing to the medium, the logical address "0" of the specified deck is stored in the address conversion means 1.
Send to 1.

The address conversion means 11 converts the physical address 112 . That is, in this case, "0" is sent to the interface circuit 17 and deck #0 is selected. When the deck is selected, the microprogram processing section 13
The EAD/WRITE circuit 16 is instructed to start transferring the data in the buffer 14, and the data is written to the medium loaded on deck #0.

When a failure occurs in deck #0 and processing cannot be executed, the microphrogram processing unit 13 checks the deck status storage unit 121 in the deck control table 12 to determine whether the medium is not loaded or occupied by the host device. Look for the missing deck. If the deck with logical address "7" is unused, position information etc. necessary for error recovery processing are stored in the error information storage section 122 of the deck control table 12 corresponding to logical address "0". Then, accessor 3 takes out the medium from deck #0 with physical address "0", and
Specify the seed to be loaded into deck #7 at physical address "7". Further, the logical address 11 of the address conversion means 11
The correspondence between 1 and the physical address 112 is changed as shown in FIG. 2(b).

When the movement of the medium to deck #7 with physical address "7" is completed, the medium is repositioned so that processing can be resumed based on the contents of the error information storage section of the deck control table 12 corresponding to the logical address rOJ.

Also, the deck state storage unit 1 corresponding to the logical address “7”
At 21, the deck is set to be offline.

As a result, the faulty deck #0 with the physical address "0" is replaced with the deck #7, and it appears to be the same as if a fault had occurred in the deck with the logical address "7" that was not used by the higher-level device, and the logical address The input/output request executed with "0" is executed normally, and subsequent processing is performed without changing the address of the deck to be specified from the higher-level device. automatically changes the deck to be selected and processes the same medium.

〔Effect of the invention〕

As explained above, the peripheral control device of the present invention maintains a correspondence between the logical address of the deck and the physical address within the peripheral control device even when a deck failure occurs and input/output requests from the host device cannot be executed. By changing 9- and moving the medium using the accessor, it becomes possible for the host device to continue processing without being aware of the occurrence of a deck failure.

In particular, in the case of a peripheral control device that uses a large-capacity buffer to write to the medium asynchronously with write commands from the host device, the host device must recover unwritten data in the buffer when a deck failure occurs. Therefore, it is possible to avoid a situation where error recovery processing cannot be performed because a storage area for data recovery cannot be secured, and the burden on the software can be reduced.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing a configuration example of a library type magnetic tape subsystem using the peripheral control device of the present invention, and FIG. 2 is an explanatory diagram showing the concept of address conversion means. 1...Peripheral control device, 2...Cell, 3
... Accessor, 11 ... Address conversion means, 12 ... Deck control table, 13 ...
...Microprogram processing 10- Ring part, 14...Buffer, 15...I
10 control unit, 16...READ/WRITE circuit, 17...interface circuit.

Claims (1)

[Claims] A library-type peripheral device includes a plurality of decks for writing and reading data on and from media, cells for storing media, and accessors for moving media between the cells and the decks and between the decks. In the peripheral control device to be controlled, an address conversion means that stores and can arbitrarily change the correspondence between the physical address of each of the decks and the logical address used at the time of an input/output request from the host device; A deck status storage unit that stores information such as whether or not a medium is loaded on the deck and whether it is occupied by a command from a higher-level device, and location information that is necessary for recovery processing when a deck failure occurs. and a deck information management means including an error information storage unit for holding error information, and when a fault occurs in a deck executing a command from a host device, the deck information management means is referred to to search for an unused deck and detect the fault. 1. A peripheral control device comprising: failure processing means for instructing execution of recovery processing by moving the medium in the deck where the problem occurred, and changing the memory of the corresponding deck portion of the address conversion means.