CN1089916C - Method for reading identification value of interface device of small computer system - Google Patents

Abstract

A method for reading Identification value (Device Identification) of Small Computer System Interface (SCSI) Device reads Identification value of SCSI Device for several times, and takes the Identification value with highest frequency as the Identification value of the Device, so that the system is not influenced by Static-Static Discharge (ESD) when reading the Identification value of SCSI Device, and no extra metal sheet is needed to increase to conduct the burst current generated by Static, thereby being a method for correctly reading Identification value of SCSI Device at any time.

Description

Method for reading identification value of interface device of small computer system

The invention relates to a method for correctly reading the identification value of the interface of the small computer system, that is, the device. The identification value of the interface device of the small computer system is read multiple times, and the identification value of the device with the highest frequency of occurrence is used as the identification value of the device. In this way, the system will not be affected by (Electro-Static Discharge, abbreviated as ESD) when reading the identification value of the small computer system interface device, and there is no need to add additional metal sheets to conduct the sudden current generated by the static electricity .

Small Computer Systems Interface (SCSI) series products have been widely used in various computer devices, such as hard disk (Hard disk), high-capacity read-only memory (Compact Disk Read Only Memory, CD-ROM) ) and other devices have products that conform to the interface, and each device that conforms to the SCSI interface has a unique identification value to facilitate the system to store and retrieve device signals (information).

In the natural environment, sudden static electricity is often generated, and the static electricity often generates instantaneous large currents. Take the relationship between the current and time induced by static electricity in Figure 2, and cooperate with the four levels of static electricity and its induced current listed in Figure 3 as an example. Regardless of the size of the static electricity charge, it is within 0.7 to 1 billionth of a second Within (Nano second, ns), the induced current will rise to the highest point and decrease with time. For example, the current caused by static electricity of 4 kilovolts (Kilo Volts, KV), the first current peak value (point A in Figure 2) caused by it is as large as 15 amperes (Ampere)! And at 30 billionths of a second (nano second, ns) point B in Figure 2 and point C in 60ns Figure 2), the induced currents are 8 and 4 amperes respectively, and this induced current increases with the electrostatic voltage increase and increase.

For extremely sensitive current systems, some unpredictable errors are often caused by static electricity interference. For example, when reading the SCSI device identification value, the read device identification value is often wrong due to static electricity interference. The case of the identification value. Based on this shortcoming, the traditional method is to use a metal sheet to wrap the outside of the SCSI device, so the electric current caused by the static electricity is guided to the appropriate position by the additional metal sheet and then released. However, this method must add a metal sheet, and what is more serious is that the protective effect will not be reached when the metal sheet is damaged. Therefore, there is an urgent need for a method that can still read the SCSI device identification value correctly under the interference of static electricity. Methods.

In view of the above-mentioned background of the invention, in order to overcome the situation that reading errors often occur due to the interference of static electricity when reading the identification value of the SCSI device in the traditional device, if a metal sheet is used to wrap the outside of the SCSI device to prevent static electricity To read the identification value of the SCSI device, a metal sheet needs to be added, so the purpose of the present invention is to provide a method that can correctly read the identification value of the SCSI device at any time.

In order to achieve the above object, the present invention provides a method for reading the identification value of a small computer system interface device, which is characterized in that the method at least includes the following steps:

Obtain a plurality of sampling values of the identification value of the small computer system interface device in a sampling manner, and the sampling manner is performed at a period of at least 60 billionths of a second;

find the most frequent of the sampled values; and

The identification value of the interface device of the small computer system is taken as the sampling value with the highest occurrence frequency.

The above-mentioned method, wherein, the step of finding out the identification value of the small computer system interface device obtained multiple times needs to be performed at least three times.

The above-mentioned method, wherein, the sampling method is performed at least three times.

A method for reading the identification value of an interface device of a small computer system, which is characterized in that the method can still correctly read the interface of the small computer system without adding additional metal sheets for protection and in an environment affected by static electricity. Identify the value, at least including the following steps:

Obtaining at least three sampling values of the identification value of the small computer system interface device in a sampling manner, and the sampling manner is performed at least at a period of 60 billionths of a second;

find the most frequent of the sampled values; and

The identification value of the interface device of the small computer system is taken as the sampling value with the highest occurrence frequency.

The above method, wherein the sampling method is performed at least three times.

According to the above, the present invention provides a method for correctly reading the identification value of the SCSI device. When reading the identification value of the SCSI device, multiple sampling (Sampling) is used, and the identification value with the highest frequency of occurrence The device identification method does not need to add additional metal sheets to conduct the sudden current generated by the static electricity, so that the system will not be affected by ESD interference and the environment when reading the SCSI device identification value.

Preferred embodiments of the present invention will be described in more detail with the help of the following drawings in the following description:

Fig. 1 is the operation flowchart of the present invention in reading SCSI device identification value;

Fig. 2 is a typical electrostatic induction current versus time diagram; and

Figure 3 is a corresponding chart of static electricity and its induced current.

Fig. 1 describes the operation flow of the present invention in reading the identification value of the SCSI device. When the computer system reads the identification value of the SCSI device, it will read the identification value many times in the form of sampling (step 101), that is, the identification of the sampling Values are classified, and the occurrence times of the sampling values are counted (step 102), and finally the sampling value with the highest frequency of occurrence is the SCSI device identification value (step 103).

For example, when the computer system samples 10 times with a sampling period of 30 ns to read the SCSI hard disk with an identification value of 1, there happens to be a current induced by static electricity, so the identification value read by the computer system in step 101 is "1". , 1, 4, 4, 3, 1, 1, 1, 1, 1". After counting the number of occurrences of the sampling value, it is found that "identification value 1 appears 7 times, "identification value 4" occurs 2 times, and "identification value 3" occurs 1 time (the classification result of step 102), so the "identification value" with the highest frequency of occurrence 1" is the identification value of the SCSI hard disk. If the above-mentioned situation is carried out in the usual way of only reading the identification value once, it is very likely to read a wrong identification value (such as 3 or 4), and this wrong identification value will cause Serious consequences of system crashes.

The above-mentioned sampling period and sampling frequency can vary depending on the actual situation, but the sampling frequency needs to be at least cubic to have a reference value, because when counting the sampling values, if one sampling value is different from the other two sampling values, it can still be Use the sampling value with higher frequency to identify the SCSI device. However, in the case of severe static electricity, the sampling values of the three times may be different. According to the experimental results, the best result is obtained by using a sampling period of at least 60 ns and sampling at least three times. Moreover, the system can still read the SCSI identification value correctly without the extra metal sheet to block static electricity.

As for the method of counting the sampled value, the counter or buffer can be used to store the occurrence times of the sampled value, and then the highest sampled value can be found by searching in the counter or buffer. And the implementation of the present invention can utilize the mode of software program to realize, or utilize hardware to record the operation process of the present invention, such as operating program is burnt in read-only memory (Read Only Memory, ROM), or is stored in non-volatile memory Among the bulk flash memory (Flash Memory), electronically erasable programmable read-only memory (Electrically Erasable Programmable Read Only Memory, EEPROM).

Based on the above, the present invention discloses a method for correctly reading the identification value of a SCSI device. By reading the identification value of the SCSI device multiple times and using the identification value with the highest frequency of occurrence as the identification value of the device, The system can still correctly read the identification value of the SCSI device without adding additional metal sheets to isolate static electricity.

Claims (5)

1. the read method of an identifier of interface of mini-computer system, it is characterized in that: this method comprises the following step at least:

Obtain the sampling value of plural number time this identifier of interface of mini-computer system with sampling mode, described sampling mode carries out with the cycle of 60ns at least;

Find out frequency of occurrences soprano in this sampling value; And

With the highest sampling value of this frequency of occurrences is this identifier of interface of mini-computer system.

2. the method for claim 1 is characterized in that, the described step of finding out this identifier that obtains repeatedly this interface of mini-computer system need be carried out three times at least.

3. the method for claim 1 is characterized in that, described sampling mode carries out in 3 times the mode of taking a sample at least.

4. the read method of an identifier of interface of mini-computer system, it is characterized in that: this method is protected at the bag that need not increase extra sheet metal, and be subjected under the environment of electrostatic influence, still can correctly read the identifier of small computer system interface, comprise the following step at least:

Obtain the sampling value of at least three these identifier of interface of mini-computer system in the mode of sampling, described sampling mode carries out with the cycle of 60nS at least;

Find out frequency of occurrences soprano in this sampling value; And

With the highest sampling value of this frequency of occurrences is this identifier of interface of mini-computer system.

5. method as claimed in claim 4 is characterized in that, described sampling mode is to carry out in 3 times the mode of taking a sample at least.

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