JPS6215897B2 - - Google Patents

Description

[Detailed Description of the Invention] (1) Technical Field of the Invention The present invention provides an IPL retry processing method, particularly an initial program load (IPL) processing from a direct access device with duplicated access paths, to a single access - This relates to an IPL retry processing method that increases system availability by automatically retrying the process any number of times from other access paths even if the path has a fixed failure.

(2) Background and Problems In general, duplication of access paths to direct access device (DASD) subsystems is provided primarily for the purpose of improving performance and as a remedy against path failures.

FIG. 1 shows an example of path duplication for a DASD subsystem. In the figure, 1 is the central processing unit (CPU), 2-
1, 2-2 are channel devices, 3, 3-1, 3-2
represents a disk control device, and 4-1 to 4-3 represent magnetic disk devices.

Duplication of access paths can be achieved, for example, when two channel devices 2-1 and 2-2 are connected to the disk control device 3 as shown in FIG. 1A,
As shown in FIG. 1B, a channel device 2-1 and a disk control device 3-1, or a channel device 2-2 and a disk control device 3-2 may be connected to each other. In any case, access to the magnetic disk device 4-1, etc. is through the first access
This is possible from both the path (PATH1) and the second access path (PATH2). access·
The path usually consists of a channel number, controller number,
Determined by the machine number associated with the unit number.

Before starting the operation of the system, it is first necessary to initialize various states for system operation. The CPU 1 sequentially fetches and executes instructions on the main memory, but it is particularly necessary to first load the instructions to be executed onto the main memory. This loading is called an initial program load (IPL) and is performed from a specific system resident volume mounted on a direct access device such as a magnetic disk drive. After the initial settings of the system are completed, input/output to the magnetic disk device 4-1 etc. is performed using the above two access paths, since the input/output control section of the operating system is already prepared in the main memory. Access is possible from either path, and if either path becomes a failure, input/output processing from the other access path is automatically executed. However, during IPL,
Since the input/output control unit mentioned above is not prepared in main memory, conventionally, IPL was performed only on the specified main access path, and if it failed, the IPL was terminated without using the alternate path. It had been.

Therefore, duplication of access paths has no meaning during IPL, and especially in unmanned driving systems, if there is a failure in the main path, the system will not be able to start up, resulting in a large loss. It was.

(3) Object and structure of the invention The present invention aims to solve the above-mentioned problems by making it possible to specify two access paths for IPL and the number of retries for IPL processing in advance, and automatically retrying the specified first access path. By repeatedly retrying from the access path and retrying from the second access path, IPL from the alternate path is possible even when the main path has a fixed failure.
The purpose is to make it possible. Therefore,
The IPL retry processing method of the present invention provides a data processing system that includes a system resident volume on a direct access device connected via a plurality of different channel devices and has duplicated access paths, and performs IPL from the system resident volume. In the startup processing method, an IPL machine number setting means for specifying an IPL machine number for each of the first path and the second path of the access path, and a re-IPL process that is repeated when the IPL process is unsuccessful. A retry count setting means for specifying the number of attempts, and the above-mentioned retry count until the IPL process is normally completed for each of the first pass IPL machine number and the second pass IPL machine number instructed by the IPL machine number setting means. The present invention is characterized by comprising a retry processing means for retrying the IPL process as many times as instructed by the setting means. Embodiments will be described below with reference to the drawings.

(4) Embodiment of the Invention FIG. 2 shows the configuration of an embodiment of the present invention, and FIG. 3 is a process explanatory diagram of a retry processing section according to the present invention.

In the figure, numerals 1 to 4-2 correspond to FIG.
5 is a service processor (SVP), 6 is a display console, 7 and 8 are IPL machine number setting registers, 9 is a retry count register, 10 is a retry processing unit, 11 is an alternate path execution counter, 1
2 represents a plus 1 circuit, 13 represents a floppy disk, and 14 represents a retry counter.

The service processor 5 is a subsystem that has one processor independent of the central processing unit (CPU) 1, and can collectively monitor, operate, and control the system configured by the CPU 1, etc. It is something. Display console 6 dedicated to service processor 5, floppy
It has devices such as disk 13. Other general functions and configurations of the service processor 5 are well known and will not be described here.

For example, assume that a system resident volume is mounted on the magnetic disk device 4-1, and that the IPL record of the system is provided in this system resident volume. This IPL record stores a program for loading the core of the operating system onto the main memory, and when the IPL is operated, the IPL record is first read into the main memory. Access to the magnetic disk device 4-1 can be performed via a first access path via the channel device 2-1 or a second access path via the channel device 2-2.

The IPL machine number setting register 7 is set with the IPL machine number that specifies the above-mentioned first access path.
The machine number setting register 8 has the above-mentioned second access
The IPL machine number that specifies the path is set. these
The machine numbers are set in the IPL machine number setting registers 7 and 8 by inputting a command from the display console 6. Further, this content is stored in the floppy disk 13, and is read out from the floppy disk 13 and set when automatically executing IPL in an unmanned driving system or the like.

The retry count register 9 is a register in which the number of times to retry is set when input processing of an IPL record from the magnetic disk device 4-1 does not go well. IPL machine number setting register 7, 8
As in the case of , the settings are made by input information from the display console 6 or the floppy disk 13. For example, if the failure on the access path is a fixed and permanent failure, input processing will not be recovered even by retrying from the same access path, but in the case of an intermittent failure due to noise etc. It may be recovered by input processing from the same access path.

When the alternate path execution counter 11 is "0", input processing from the first access path is executed;
This counter indicates execution of input processing from the second access path when it is "1" and indicates completion when it is "2". The retry counter 14 is a counter that counts the number of retries, and the plus-one circuit 12 operates every time a retry is made. The retry processing unit 10 actually executes an IPL retry, and processes as shown in FIG. 3.

When an IPL request is issued to the service processor 5, the retry processing unit 10 is activated. The retry processing unit 10 first clears the alternate pass execution counter 11 to zero by the process 20 shown in FIG. Then, in step 21, the retry counter 14 is cleared to zero, and in step 22, it is checked whether the alternate pass execution counter 11 is zero. Since it is zero at first, process 23
to select the first access path and IPL
The IPL machine number "XXXX" from the machine number setting register 7 is set, and in process 25, the channel device 2
-1. Execute input/output commands to the magnetic disk device 4-1 via the disk control device 3.
That is, the IPL record is read into the main memory. In process 26, it is determined whether the input/output process in process 25 was successful. If successful, control is transferred to the CPU 1 as a normal end.
In the case of abnormal termination, processing was conventionally stopped at that point, but in the present invention, processing is further continued as follows. By processing 27, plus 1 circuit 1
2 and set the value of retry counter 14 to 1.
Count up. Then, in step 28, it is determined whether the contents of the retry counter 14 have become equal to the contents of the retry count register 9. If they are not equal, perform the previous process 22.
Return to and repeat the process. Therefore, if the process does not end normally, the IPL process from the first access path will be retried by the value of the retry count register 9 in process 25.

If the determination in process 28 is equal, it is regarded as a fixed failure, and in process 29 error information is collected and stored in the floppy disk 13. Next, in step 30, the alternate pass execution counter 11 is incremented by +1. Then, in process 31, it is determined whether the execution from the alternate path has been completed. If the value of the alternate pass execution counter 11 becomes "2", it is determined that the process has ended. The replacement pass execution counter 11 is initially “0”.
Since it has only been counted up from 1 to 1, it has not become 2. Therefore, process 21
Return to and repeat the process. However, processing 2
Since the judgment in 2 is "NO", this time,
Process 24 causes IPL of the second access path.
The machine number "YYY" is read from the IPL machine number setting register 8 and set, and input/output to and from the magnetic disk device 4-1 is executed from the path on the channel device 2-2 side. If this second access path does not end normally, it will be retried the number of times set in the retry count register 9.
After the error information is collected, a process 30 includes:
The substitution pass execution count 11 is counted up from "1" to "2". Therefore, the process 31 determines that the process has ended with an error.

(5) Effects of the Invention As explained above, according to the present invention, an arbitrary number of retries are automatically executed for each of the duplicated paths, and intermittent failures and fixed failures of one access path can be avoided. It can be rescued. Particularly in unmanned driving systems, etc., even if the above-mentioned failure occurs, the system can be started up without operator intervention, which is highly effective.

[Brief explanation of the drawing]

FIG. 1 shows an example of path duplication in a DASD subsystem, FIG. 2 shows the configuration of an embodiment of the present invention, and FIG. 3 shows a process explanatory diagram of a retry processing section according to the present invention. In the figure, 1 is a CPU, 2-1 and 2-2 are channel devices, 3 is a disk control device, 4-1 is a magnetic disk device, 5 is a service processor, 6 is a display console, and 7 and 8 are IPL machines. number setting register, 9 is retry count register, 1
0 represents a retry processing section.

Claims (1)

[Claims] 1. Startup of a data processing system that includes a system resident volume on a direct access device connected via a plurality of different channel devices and has duplicated access paths, and performs IPL from the system resident volume. In the processing method, an IPL machine number setting means for specifying an IPL machine number for each of the first path and the second path of the access path, and the number of retries of the IPL process to be repeated when the IPL process is unsuccessful. a retry count setting means for specifying the number of retries, and a first path specified by the above-mentioned IPL machine number setting means.
The present invention is characterized by comprising a retry processing means for retrying the IPL processing for each of the IPL machine number and the second path IPL machine number for the number of times instructed by the retry count setting means until the IPL processing is normally completed. IPL retry processing method.