JPH07182145A - Generating device for initial value of random number - Google Patents

Abstract

PURPOSE:To generate the initial value of different random numbers every time a computer system is restarted by processing the data value stored in a storage means kept in an uninitialized state into the initial value and storing temporarily this initial value. CONSTITUTION:An initial value arithmetic control means 2 controls an initial value arithmetic means 4 so that it can start when a computer and an operating system are started. The means 4 divides the data which are stored in an entire part or a part of a storage means 3 into the basic units. When the initial value is calculated out of those data stored in the storage means 3, such a method is applied that the result of calculation can be satisfactorily scattered. The calculation result of the initial value obtained by the means 4 is stored in a temporary storage means 5. The initial value of a random number is calculated in such a way so that the random numbers of different time series are generated at each time without using any special hardware. Thus the uniformity of random numbers is improved.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a random number initial value generator, and more particularly to a device for generating an initial value when a random number is generated in a built-in small computer system for controlling equipment.

[0002]

2. Description of the Related Art Conventionally, as a method for generating a random number, there is a method using a physical random number source or an arithmetic random number. The physical random number source is a case where a physical phenomenon that can be detected as noise from an electron tube or noise from a radioactive substance, for example, gamma decay of a radioisotope is used. On the other hand, the arithmetic random number is calculated as f Xn + 1 = f (Xn-m, Xn-m + 1, ..., Xn-1, Xn) to a certain initial value (X0, X1, X2, ... Xm). ) Is used to generate pseudo-random numbers one after another. This arithmetic operation f is a simple arithmetic operation and discards overflow digits. The present invention relates to random number generation based on this arithmetic operation.

As for the random numbers by such arithmetic operation, a random number sequence having periodicity is generated as long as the operation operation is the same. Even if the initial value is changed, if the arithmetic operations are the same, the start of the random number sequence will be shifted and the random number sequence in exactly the same order will be repeated. However, if this cycle is sufficiently long, it can be said that the random number sequence is sufficiently practical. Therefore, when the random number generation is started in this way, when it is desired to start the random number generation at different points in the random number sequence having periodicity, the initial value must be set to be different each time. For such a method, use the time at the time of random number generation as an initial value,
Alternatively, a method is used in which the last-generated random number value is stored in a rewritable non-volatile memory and is used when the initial value is set next time.

On the other hand, in a computer system that does not have special hardware such as a rewritable non-volatile memory or a time generator, for example, a computer system in which a small device is incorporated, the same initial value for random number generation is always used. There is a drawback that the values must be used and a random number sequence in a fixed order is always generated in time series.

[0005]

SUMMARY OF THE INVENTION The present invention solves the problems described above, and in an embedded type small computer system for device control, an initial stage for random number generation without using special hardware. It is an object of the present invention to propose an apparatus that creates a different value and creates a different initial value each time the computer system is restarted.

[0006]

In order to solve the above problems, a random number initial value generating device according to a first aspect of the present invention is a random number generating device that operates in a computer having at least a storage device and a central processing unit. Storage means having an uninitialized state at the time of starting up, an initial value calculation means for calculating an initial value of a random number from the data value of the uninitialized state in the storage means, and an initial value obtained by the initial value calculation means. It is characterized by having a temporary storage means for temporarily storing a value and an initial value calculation control means for controlling the initial value calculation means to be activated when the computer is started up.

[0007]

In the random number initial value generating device of the present invention, the initial value operation control means activates the initial value operation means when the computer is started up, and the data values in the storage means which are in the uninitialized state are stored in the initial value operation control means. The value is processed for the initial value, and the value is temporarily stored in the temporary storage means. After that, the value is used as an initial value for random number generation as needed. Therefore, different time series random numbers can be generated each time without using special hardware, and the uniformity of the random numbers can be improved. Also, because no special hardware is required,
It is suitable for using random numbers in equipment that applies a small embedded computer.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail below with reference to the drawings. FIG. 1 is a block diagram showing an embodiment of a random number initial value generation device of the present invention. The random number initial value generation device 1 constitutes a part of the operating system, and has an initial value calculation control means 2 for triggering the calculation of the initial value of the random number, and a memory which is in an uninitialized state when the computer is started up. Means 3, an initial value calculation means 4 for calculating the contents of the storage means 3 in the uninitialized state for calculating an initial value, and a temporary storage means 5 for temporarily storing the calculated initial value ( Register).

Generally, the data in the storage device immediately after the power is turned on is either 0 or 1, but not all the data in the storage device is either 0 or 1, and normally it is not. 0 and 1 are in a state of showing an irregular pattern. Therefore, it becomes necessary to initialize to a specific state (for example, all 0s) before starting calculation processing in the central processing unit. This initialization work is executed, for example, by a method in which the operating system itself writes data of all 0s to the storage device immediately after the operating system of the computer starts to operate. The initial value calculation control means 2 controls so that the initial value calculation means 4 can be activated at the start of the operating system when the computer starts up.

The initial value calculating means 4 determines the initial value of the random number as follows. First, the data stored in the entire storage means 3 or a part of the storage means 3 is divided into certain basic units. The size of the basic unit may be an access unit of the storage device or a plurality of bytes such as 1 byte, or may be an arbitrary length such as 10 bits which is not an access unit. As for the way of division, the storage means 3 may be divided by the length of this basic unit, or may be divided at a certain interval (see FIG. 2). Possible methods for calculating the initial value from the storage means 3 thus divided are: -summing the values for each basic unit; -calculating the exclusive OR of the values for each basic unit. For example, the following various methods are possible. -Add all the data in the storage device byte by byte and use the lower 4 bytes of the total value as the initial value. -The exclusive OR of all the data in the storage device is calculated every 2 bytes, and the value of 2 bytes of the final result is used as the initial value. The data in the storage device is added every 3 bits in 3-bit units, and the lower 8 bits of the total value are used as the initial value. The method of calculating the initial value is not limited to the method described here, and any method may be used as long as the dispersion of calculation results (the range of numerical values) is sufficiently large. Further, in this embodiment, the storage means 3 is divided and the initial value is calculated, but data having a required length may be taken out from an arbitrary address and used as the initial value without being divided.

The calculation result of the initial value obtained by the initial value calculation means 4 is stored in the temporary storage means 5. The temporary storage means 5 can use an area that is not initialized, for example, a register inside the central processing unit. The initial value calculation control means 2 controls so that the initial value thus obtained is temporarily saved in the register and then the data in the storage device is initialized. After that, a random number sequence is generated using the initial value saved in the register as needed.

In this way, when the initialization of the data in the storage device and the setting of the initial value of the random number are completed, and the central processing unit starts executing the calculation processing, the central processing unit in the storage device stores Data that is constantly updated is stored, such as intermediate calculation results, saved data of states, and various counting results. Therefore, once the central processing unit starts execution of the calculation process, the data in the storage device is always changing, so the calculation process was interrupted and re-executed from the calculation of the initial value of the random number formula. Even in this case, it is unlikely to use the same initial value as last time.

When a plurality of random number sequences require different initial values, the storage means 3 is divided into a plurality of parts and each part is calculated to obtain a plurality of initial values.
A method is conceivable in which a random number sequence is generated from one initial value, a predetermined number of them are taken out, and used as the initial value of each random number sequence.

As described above in the present embodiment, in the uninitialized state immediately after power-on or at the time of re-execution after the interruption of the calculation process, the data in the data storage device is randomized only from the uninitialized data. Since the initial value is created, different time series random numbers can be generated each time without using special hardware, and the uniformity of the random numbers can be improved.
Further, since it requires no special hardware at all, it is suitable for using a random number in a device to which a small embedded computer is applied.

[0015]

As described above, according to the first aspect of the present invention, the data in the data storage device is irregular in the uninitialized state immediately after the power is turned on or at the time of re-execution after the interruption of the calculation process. Since the random number initial value is created from the irregular data by using, it is possible to generate different time series random numbers each time without using special hardware, and it is possible to improve the uniformity of random numbers. Becomes Further, since it requires no special hardware at all, it is suitable for using a random number in a device to which a small embedded computer is applied.

[Brief description of drawings]

FIG. 1 is a block diagram of an embodiment of a random number initial value forming device according to the present invention.

FIG. 2 is a diagram for explaining how to divide the storage means of the present invention.

[Explanation of symbols]

 1 ... initial value generator for random number 2 ... initial value calculation control means 3 ... storage means 4 ... initial value calculation means 5 ... temporary storage means.

Claims (1)

[Claims] 1. A random number generator operating on a computer having at least a storage device and a central processing unit,
Storage means having an uninitialized state when the computer is started up, initial value calculation means for calculating an initial value of a random number from the data value of the uninitialized state in the storage means, and the initial value calculation means And a temporary storage means for temporarily storing the initial value, and an initial value calculation control means for controlling the initial value calculation means to start when the computer is started up. Characteristic random number initial value generation device.