JPH05204815A - Time oriented storage control system - Google Patents

Abstract

PURPOSE:To obtain a storage device which suitably stores video information whose responsiveness in fixed with at fixed speed is important by securing uniform responsiveness as to total access. CONSTITUTION:A time control part 32 is provided in an I/O processor 3 between a main processor 1 and a storage device 4. Then a storage area 321 for a permitted time span is provided on the time control part 32. When optional one task among plural tasks of the main processor 1 gains successive access, one of divided time spans is assigned and only access from a permitted task is allowed in the time span. When the residual time spans can not be assigned, the task is informed that access is disabled. Consequently, the instantaneous response of access can be secured for all the tasks assigned to the time spans and real- time access is stably gained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to video and audio information data recording.
Regarding a storage device control system used for storing a table,
In particular, the present invention relates to a time-oriented storage control system suitable for storing information that emphasizes constant response performance.

[0002]

2. Description of the Related Art Conventionally, a magnetic disk or an optical disk has been used as a storage element of a database system. An information processing system having a database generally stores information in a main processor 1, a main storage device 2 which is a work area thereof, and a medium such as a magnetic disk or an optical disk, as shown in FIG. It is composed of a memory device 4 and a data transfer path 3 connecting the main processor 1 and the memory device 4. It should be noted that although control devices are connected to the magnetic disk and the optical disk, respectively, these control devices are considered here as a part of the data transfer path 3 in a broad sense. In order to efficiently operate a database or the like, as shown in FIG. 5, it is common to consider a logical access subject having a plurality of functions by the concept of tasks, and these tasks are In an environment with a plurality of these tasks, these tasks realize functions independently or as necessary, communicating with each other.
The information accessed by these tasks is generally stored in locations independent of each other. On the other hand, when information with strong real-time property such as video and audio is databased and access from multiple tasks is permitted, immediate response is not guaranteed for a specific task, It is required to guarantee stable real-time access for all tasks. Because these information must be processed at a constant rate (often,
This is because it is a reproduction process), which causes disturbances and breaks in the video / audio.

[0003]

In the interface between the conventional main processor 1 and the storage device 4 shown in FIG. 5, a command designating the required number of bytes or a required number of blocks called a sector is executed by the main processor 1 Storage device 4
To be issued to. In particular, in a system that is conscious of high-speed information transfer, DMA (Direct Memory)
ess) transfer method called main transfer 1
Is a device that controls I / O (I / O
It is general to let the O processor) manage the transfer state and perform the processing for other tasks. At this time, the I / O processor writes the information read from the storage device 4 directly into the designated I / O buffer on the main storage device 2. In this case, in the conventional storage device 4, regardless of the access time or transfer time required for the transfer, the amount of information specified by one command is transferred to one I / O.
As an operation, reading or writing processing is performed. When a plurality of accesses to the storage device 4 occur, control is performed according to a so-called FIFO algorithm, in which I / O processing is sequentially performed from the first access accepted. Further, when a plurality of accesses compete for the same access unit, the main processor 1 performs the queuing control for waiting for the end of the immediately preceding access. This method is an excellent method from the viewpoint of fully utilizing the capacity of the storage device 4. However, when a large amount of data transfer occurs on the way, or when the load momentarily increases, the response time greatly changes. Further, in a rotary storage device such as a magnetic disk device, the transfer path 3 is temporarily logically separated while the physical movement of the position of the head or waiting for rotation is accompanied by access.
A method of improving the throughput as a storage subsystem by an offline operation that operates alone is generally used. However, this method can also cause a large change in response performance when the load changes. When the load is extremely high, a so-called subduction phenomenon appears.

FIG. 6 is a typical data transfer time chart in a conventional storage subsystem. As shown in FIG. 6, inside the main processor 1, when a plurality of accesses compete for the same access unit, an I / O command is queued and sent to the I / O system. These I / O commands (I / O access) are described as Task 1, Task 2, and Task 3 below, and since Task 2 received the access first, the waiting time was short, and the processing moved first. , Then task 3 moves to processing,
Finally, after a long waiting time, the task 1 moves to the processing. Figure 4
FIG. 4 is a diagram showing an example of evaluation of a very typical response characteristic when access is randomly generated and a transfer amount follows an exponential distribution. Here, 64KB transfer, transfer speed 4MB /
s, access time is 35 ms, and 4 per IOC
It shows a case where a number of IODs are connected. As shown in FIG. 4, good response characteristics can be expected when the load is low, but when the load is concentrated even momentarily, the response performance deteriorates several tens of times or more. Since the fluctuation of the load from the host device cannot be predicted on the storage device 4 side, the conventional storage device 4 has no method for preventing these performance deteriorations. When the code information is mainly stored as in the conventional storage device 4, this problem is not so fatal, but when the video information is stored, each response time is extremely short. On the contrary, the worst case response performance is required within a certain time, that is, the next information is required to be read into the memory before the next continuous information is reproduced. Therefore, if it is applied as it is, there is a problem that the video information may not be reproduced at the expected speed or may not be reproduced. That is,
The conventional storage device is designed with emphasis on the output of the device, and is not suitable for converting information such as video information that emphasizes constant response performance into a database. It was An object of the present invention is to solve such a conventional problem of a variation in response performance that cannot be predicted from a higher-level device, and store information such as video information that emphasizes constant response performance. To provide a suitable time-oriented storage control system.

[0005]

In order to achieve the above object, a time-oriented storage control system of the present invention is shared among a plurality of access subjects, and information of an address designated by each access subject is stored in the access subject. In a storage control system that transfers data between a storage device and a storage device, a time management unit that manages time and a storage area that stores a permitted time frame managed by the time management unit are provided in the system. , The real time is divided into a plurality of time frames that are evenly or non-uniformly allocated at a fixed cycle, each time frame is identified, and one time is divided for a series of accesses from any access subject. After allocating a frame and recording it in the storage area, it is controlled so that only the access from the authorized access subject is permitted within the time frame, and another If the access entity attempts to access, if it is not possible to allocate the remaining time period, and notifies the inability access to the access subject, is characterized in that denied the.

[0006]

In the present invention, the time management unit is provided in the data transfer path between the main processor and the storage device, for example, in the I / O processor. Then, a storage area for the permitted time span is provided in the time management unit. The time span is a real time divided into uniform or non-uniform small times, and is divided into a plurality of time spans allocated at a constant cycle, and each time span is identified by an identifier. Then, when a series of accesses are made from any one of the tasks of the main processor, one of the divided time spans is allocated, and only the access from the permitted tasks is performed within the time span. Control to allow. If the remaining time span cannot be assigned, the task is notified that it cannot be accessed. This allows
It is possible to guarantee an immediate response to all tasks whose access is allocated to a time span, and to perform stable and real-time access. as a result,
It is possible to store video and audio information in a database so that the video and audio are not distorted or discontinuous, and moving images and audio information can be used under favorable environmental conditions.

[0007]

Embodiments of the present invention will now be described in detail with reference to the drawings. FIG. 1 is a block diagram of a time-oriented storage control system showing an embodiment of the present invention. In the present embodiment, in order to make information such as video information that emphasizes a certain response performance into a database, the configuration of the data transfer path 3 is particularly changed. In FIG. 1, 10
Reference numeral 1 is a system bus commonly connected to the main processor 1 and the main storage device 2, 3 is an I / O processor also connected to the system bus 101, and 102 is a storage device bus connected to the I / O processor 3. 41 is the bus 10 of the storage device
2 is a storage control device connected to 2, and 42 is a divided storage unit of the storage device 4. Inside the I / O processor 3,
Microprocessor 31, time management unit 32, and extender
Null port controller (external input / output controller) 34
Further, a storage area 321 of a permitted time span is provided inside the time management unit 32.
The feature of this embodiment is that the following means are provided as shown in FIG. (A) The unit real time is divided into a plurality of time intervals, and the time management unit 32 and the storage area 321 of the permitted time span are provided for giving an identifier capable of recognizing the time interval. The time management unit 32 generates an internal clock with sufficient accuracy. This time span is controlled so that the same identifier is repeatedly given at a constant cycle. (B) In response to the I / O command issued from the main processor 1, the microprocessor 31 inquires of the time management unit 32 about the execution state of the executable time, allocates a vacant span, and permits the result. The time span is stored in the storage area 321. (C) At this time, if the required span cannot be allocated, the main processor 1 is notified that the access cannot be accepted. The time management unit 32
Can be realized by a software module or hardware.

First, the main processor 1 performs the I
The time required for I / O and the ID of the task to be issued are used as information, and the microprocessor 3 in the I / O processor 3
Notify 1. In general, when reading moving image information, the amount of information to be read can be estimated in advance by one operation.
Of course, when the information is compressed by the encoding technique, the information amount of the unit of reading has a variable length.
In the encoding method that is being standardized by EG (Multi-pulse Excited Group) and the like, it is possible to set a unit for reading with a substantially fixed length, and it is possible to assume a rough value for the estimation of the time. However, when random access is performed using a database, it is impossible to predict the access time when using a rotating memory device such as a magnetic disk, but at least the maximum seek time and one rotation. The sum of time is never exceeded. Therefore, the time T required for one I / O is defined by the following formula. T ≧ (maximum access time) + (maximum transfer information amount / transfer speed) (1) That is, the sum of the maximum access time and the maximum transfer information amount per unit is not exceeded. The main processor 1 notifies the microprocessor 31 of this time and the ID of the task to be issued as information. However, this time T does not necessarily have to be set dynamically, and may be set in advance for each task.

FIG. 2 (a) is a diagram showing a divided image of a unit time in the present invention, and FIG. 2 (b) is a diagram showing a structure of a storage area of a permitted time span. When the microprocessor 31 receives the I / O command issued from the main processor 1, if the command is issued by a new task, the microprocessor 31 newly allocates the designated time interval. This allocation is realized by dividing the unit real time into a plurality of time intervals in advance by the time management unit 32 shown in FIG. 1 and continuously giving a plurality of intervals to which the identifiers that can be recognized are provided. That is, as shown in FIG. 2A, the unit time is ID0,
ID1, ... ID99 is divided into intervals assigned with ID999, and ID0 and ID are also assigned to the next unit time interval.
1, ... ID 999 are assigned respectively, and this is repeated. The allocation is performed by searching the information recorded in the storage area 321 of the permitted time span,
Search for free span. The assigned span is Task I
It is recorded in the storage area 321 as a range of D and the identifier. For example, as shown in FIG. 2B, the storage area 32
It is recorded in 1. 3211 is the task ID number, 321
Reference numeral 2 is an area for recording the start span number, and 3213 is an area for recording the end span number. Those that are already allocated are scheduled so that the command will be executed in the next span that is allocated. Therefore, the commands are not executed in the order accepted by the microprocessor 31,
The commands are executed in the order of the spans assigned to the span storage area 321. The storage area 321 of the permitted time span is searched, and if there is no continuous span to be allocated, the task is notified to reject the command.

FIG. 3 is a diagram showing the relationship between the load and the response performance in the present invention. The task allocating the span issues a command for releasing the span when the access to the storage device is stopped, so that the main processor 1 gives the information about this task to the storage area 32 of the permitted time span.
Delete from 1. By performing the above control, the task to which access is once accepted and the span is assigned is guaranteed to complete I / O at a constant time interval until reading of necessary moving image information is completed. When the control according to the present invention is performed, the response characteristic is as shown in FIG. As is clear from comparison with the conventional characteristics shown in FIG. 4, in the present invention, when the load (times / second) is 30 times before,
Since it is judged that the load over which time can be allocated has been exceeded and access is further denied, the potential of the device is not fully used from the viewpoint of throughput as compared with FIG. However, from the viewpoint of the stability of the response performance, it is clear that the improvement suitable for reading a moving image or the like has been made.

[0011]

As described above, according to the present invention,
Real time is divided into spans that occur in a fixed cycle, the span is assigned to a specific access subject, and access to the storage device in that span is guaranteed until a series of accesses from that subject is completed. From the perspective of each access entity, it is possible to guarantee uniform responsiveness. As a result, it is possible to realize a storage device suitable for storing video information that emphasizes responsiveness at a constant speed and within a fixed time.

[0012]

[Brief description of drawings]

FIG. 1 is a block diagram of a time-oriented storage control system showing an embodiment of the present invention.

FIG. 2 is a diagram showing a configuration of a divided image of a unit time and a storage area of a permitted time span in the present invention.

FIG. 3 is a diagram showing a relationship between load and response characteristics in the present invention.

FIG. 4 is a diagram showing a relationship between a load and a response characteristic of a conventional device.

FIG. 5 is a diagram showing access to a storage device of a general information processing system.

FIG. 6 is a control image in the main processor of access to the conventional storage subsystem and a time chart of the access.

[Explanation of symbols]

 1 Main Processor 2 Main Storage Device 3 I / O Processor 4 Storage Device 31 Microprocessor 32 Time Management Unit 34 External Port Control Unit 41 Storage Control Device 42 Storage Unit 101 System Bus 102 Storage Device Bus 321 Permitted Time Span storage area

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Naoya Otani 1-1-6 Uchisaiwaicho, Chiyoda-ku, Tokyo Nihon Telegraph and Telephone Corporation

Claims (1)

[Claims] 1. Shared among a plurality of access subjects,
In a storage control system that transfers information of an address designated by each access subject between the access subject and a storage device, a time management unit that manages time in the system, and a time permitted and managed by the time management unit. A storage area for storing the frames is provided, and the time management unit divides the real time into a plurality of time frames that are uniform or nonuniform and are allocated in a constant cycle, identify each time frame, and identify any access subject. After assigning one of the divided time frames to a series of accesses from the user and recording it in the storage area, control is performed so as to allow only the access from the authorized access subject within the time frame, and When the other access subject tries to access, if the remaining time frame cannot be assigned, the access subject cannot be accessed Notifies the door, time Oriented Sutorejji control system characterized by denying the access.