JPH1124808A - Attachment mechanism, unit device and information processor coping with attachment and detachment of hot line - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an attachment mechanism which can properly cope with the hot line attachment/detachment of a unit device in an information processing system where plural unit devices are connected to a unit attachment substrate of an information processor. SOLUTION: The tip positions of contacts of three connectors 31a, 32a and 33a placed at the side of a unit device 22a are shifted from each other when viewed in the direction where they are put into a unit device attachment substrate 24a. On the other hand, the contacts of three connectors 41a, 42a and 43a placed at the side of the substrate 24a are located at the same position. Therefore, the contact timing is shifted from each other among the contacts of the device 22a and the substrate 24a in the order of uses for the GND, signals and the power supply respectively.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a unit device other than a unit to be inserted or removed in an information processing system in which a plurality of unit devices are connected to a unit device mounting board of the information processing apparatus. An attachment mechanism to enable insertion and removal while the
The present invention relates to a unit device having the mounting mechanism and an information processing device.

[0002]

2. Description of the Related Art There are many information processing systems that are required to operate continuously for 24 hours.
When a failure or maintenance is performed on a unit device constituting such a system, the unit device constituting the system is replaced without shutting down the power supply of the system itself or interrupting the work currently being performed. There is a need. As shown in FIG. 5, the unit equipment 22 is generally a unit equipment mounting board 2 provided in the information processing apparatus 21.
4, the control unit 23 of the information processing device 21 can exchange signals with a plurality of unit devices 22 connected via the unit device mounting board 24. Of course, the connection form is not limited to the example shown in FIG. 5, but when the unit equipment 22 needs to be replaced due to a failure or the like, the operation of the unit equipment 22 other than the unit equipment 22 to be replaced is performed. In order to replace the information processing device 21 without shutting down or shutting off the power supply of the information processing device 21, it is necessary to adopt a configuration corresponding to so-called “hot swapping”. In other words, insertion and removal can be performed while the unit devices 22 other than the object to be inserted and removed are kept in a live state.

[0003] In order to cope with such "hot-line insertion and removal",
Conventionally, for example, a configuration as shown in FIG. 6 has been adopted. That is, the connector mechanism on the unit device 22 side is the edge portion 1
As shown in FIG. 6A, a power supply contact 131 and a signal contact 132 are separated from a substrate end 125 by a distance L1, Change L2. This prevents the element from being damaged by an overvoltage when connected to the unit equipment mounting board 24 of the information processing device 21 and the adverse effect such as the fluctuation of the voltage level of the signal due to the mismatch of the voltage level.

[0004]

However, the structure of the conventional connector has the following problems. Conventionally, the distances L1 and L2 between the power supply contact 131 and the signal contact 132 from the substrate end 125 are merely changed. However, the power supply contact 131 is used for the power supply and the ground for use. It will be used for two types. However, it has not been distinguished which of the two types of contacts for power supply and ground is connected first to the information processing device 21 side. Therefore, the power supply voltage itself may fluctuate. To avoid this, it is necessary to change the contact timing of the contacts for power supply and ground, instead of combining them for power supply. I found

In addition, in consideration of changing the contact timing of the contact between the power supply and the ground, it is necessary to consider before and after the contact timing between the contact and the signal contact. In this regard, it has been found that it is desirable to make contact in the order of the ground contact, the signal contact, and the power supply contact. By connecting the signal contacts first, the high impedance state can be maintained until power is supplied, and the signals are not driven from the unit device 22 side before the signal contacts contact. That's why. That is, if the power is supplied after the contact of the signal contact as described above, the disturbance of the signal can be prevented.

Further, in the case of the card edge type, contacts 131 and 132 provided on the edge portion 122 are provided.
(See FIG. 6) is preferably applied by a method of electrolytic gold plating from the viewpoint of resistance to contact resistance and the like. This is because electrolytic gold plating can provide a thicker contact than electroless gold plating. However, when the electrolytic gold plating method is adopted, it is necessary to draw out a pattern for contacting the gold plating electrode to the substrate end. The gold-plated pattern 134 (see FIG. 6) is generally pulled out from the center of the contacts 131 and 132, but then comes into contact with the mating contact first when the connector is inserted. Even if the distance from the end of the substrate is changed between the signal contact and the signal contact, they all come into contact at the same time.

Accordingly, the gold plating pattern 134 is pulled out from the ends of the contacts 131 and 132 (see FIG. 6A), and the width W1 of the contacts 131 and 132 where the gold plating pattern 134 is not provided is reduced. The width W2 of the contact 141 of the connector on the unit device mounting board 24 side is set to be wider (FIG. 6).
(B)). As a result, the gold plating pattern 1
34 is a contact 141 on the unit device mounting board 24 side.
Although the method of preventing contact is adopted, if the position is displaced when the connector is inserted, the contact still occurs first.
This phenomenon is likely to occur when the card edge is made with a margin for the connector, and therefore, precision is required. In addition, since the connector size differs depending on the manufacturer, it may be necessary to specify to use a connector of a specific manufacturer. In addition, the distance between adjacent patterns is reduced, and the risk of short circuit increases.

To prevent this, it is conceivable to employ an electroless gold plating method, but it is difficult to increase the thickness of the gold plating, so that the durability against card insertion and removal is low. As another countermeasure, a method of shaving the gold plating pattern 134 after the gold plating process can be considered, but shaving the gold plating pattern 134 one by one is not realistic in view of the work content and the required cost.

SUMMARY OF THE INVENTION The present invention solves the above-mentioned problems, and in an information processing system in which a plurality of unit devices are connected to a unit device mounting board of an information processing device, appropriately copes with hot-swapping of unit devices. It is an object of the present invention to provide a possible mounting mechanism, and to provide a unit device and an information processing apparatus having the mounting mechanism.

[0010]

Means for Solving the Problems and Effects of the Invention According to the first aspect of the present invention, there is provided an information processing apparatus comprising a plurality of unit devices connected to a unit device mounting board of an information processing apparatus. A mounting mechanism for inserting and removing the unit device in an information processing system when the unit device is not inserted or removed while the unit device other than the unit device to be inserted or removed is kept in a live state. The contact portions of the substrate are divided into three types of groups, a ground contact, a power supply contact, and a signal contact, respectively, and the contact timing of the contact portion when attaching the unit device to the unit device mounting board Are the ground contact, the signal contact, and the power supply contact. So as to be in order, a hot-pluggable mounting mechanism, characterized in that the arrangement position of the at least one contact portion of the unit module and the unit component mounting substrate is adjusted.

According to the hot-swap mounting mechanism of the present invention,
First, the contact portions of the unit device and the unit device mounting board are divided into three types of groups: a ground contact, a power supply contact, and a signal contact. That is, what has been conventionally grouped for power supply is divided into two, a ground contact and a power supply contact. And by adjusting the arrangement position of at least one contact portion of the unit device and the unit device mounting board, the contact timing of the contact portion when the unit device is mounted on the unit device mounting board is a ground contact, a signal contact, The order of the power supply contacts is set.

As described above, when the contact timing is in the order of the ground contact, the signal contact, and the power supply contact, the following advantages can be obtained. (1) First, paying attention to the ground contact and the power supply contact, they are divided, and are contacted in the order of the ground contact and the power supply contact. Fluctuations can be prevented. (2) As described above, it is desirable to make contact in the order of the ground contact, the signal contact, and the power supply contact, but this can be realized. In other words, by connecting the signal contact before the power supply contact, it is possible to maintain the high impedance state until power is supplied,
By preventing the signal from being driven from the unit device side before the signal contact comes into contact, the disturbance of the signal can be prevented. (3) The mounting mechanism of the present invention is not limited to the card edge type, but when applied to the card edge type, the contact is advantageous in terms of resistance to contact resistance. Although it can be provided by a suitable electrolytic gold plating process, the advantage that the above-described advantage of contacting in the order of the ground contact, the signal contact, and the power supply contact can be secured can be obtained. In other words, when the electrolytic gold plating method is employed, the gold plating pattern 13 shown in FIG.
4 is pulled to the edge of the substrate. However, since the arrangement position of the contact portion is adjusted by the ground contact, the signal contact, and the power supply contact, respectively, the presence of this gold plating pattern Not affected.

As described above, in an information processing system in which a plurality of unit devices are connected to the unit device mounting board of the information processing device, it is possible to appropriately cope with hot-swapping of unit devices. Claim 2
As shown in the above, in the hot-swap mounting mechanism according to claim 1, the ground contact on the unit device side,
At least one of the three groups of signal contacts and power supply contacts may be formed as a card edge type. Then, it is conceivable that the contact portion other than the card edge type is formed by mounting a connector member. Considering this point, as shown in claim 3, in the hot-swap mounting mechanism according to claim 1, three types of groups of a ground contact, a signal contact, and a power supply contact on the unit device side are provided. Among them, it is conceivable that at least one contact is formed by mounting a connector member.

Since these are "at least one", of course, all three types of contact portions may be formed in a card edge type or a connector member may be mounted. Since the connector member is basically a separate member, the card edge type can prevent disadvantages such as an increase in the number of parts and a complicated structure and an increase in cost. In addition, there is an advantage that insertion and removal can be easily performed due to the shape of the card edge. Conversely, when a connector member is used, for example, at the stage of forming a card edge, gold plating patterns corresponding to ground contacts, signal contacts, and power supply contacts are formed in the same position, and the position of the connector itself is set. Alternatively, by adjusting the positions of the contacts, the arrangement positions of the three types of contacts can be adjusted, so that the work up to the provision of the gold plating pattern becomes easier.

In the above-described hot-swap mounting mechanism, since the arrangement position of at least one contact portion of the unit device and the unit device mounting board is adjusted, only the arrangement position of the contact portion of the unit device is adjusted. Or the arrangement position of the contact portion of the unit device mounting board may be adjusted, or both may be adjusted.

Therefore, in the case where at least the arrangement position of the contact portion of the unit device is adjusted, it can be regarded as an invention as a unit device compatible with hot-swap. In this case, as described in claim 4, when inserting and removing the unit equipment in the information processing system configured by connecting a plurality of unit equipment to the unit equipment mounting board of the information processing apparatus, A unit device having an attachment mechanism for enabling insertion and removal while the unit device is in a live state,
The unit-device-side contact portion for connecting with the contact portion of the unit-device mounting board is divided into three types of groups, a ground contact, a power supply contact, and a signal contact, and contacts from the unit device end. By providing the power supply contact, the signal contact, and the ground contact in the order of increasing the distance to the tip, the contact timing when connecting to the contact portion of the unit device mounting board Are arranged in the order of the ground contact, the signal contact, and the power supply contact.

[0017] Even when the unit is regarded as a hot-swappable unit as described above, as in the case of the above-described embodiment relating to the contact part, the three types of groups of the ground contact, the signal contact and the power supply contact are included. The at least one contact may be formed as a card edge type, and the at least one contact portion may be formed by mounting a connector member.

The functions and effects in these cases are the same as those described above with respect to the hot-swapable mounting mechanism, and will not be repeated here. In addition, when at least the arrangement position of the contact portion of the unit device mounting board is adjusted, it can be regarded as an invention as an information processing apparatus capable of coping with hot-swapping by providing the unit device mounting board. In this case, as shown in claim 7,
When inserting or removing the unit device in an information processing system configured by connecting a plurality of unit devices to a unit device mounting board of the information processing device, the insertion and removal of the unit device other than the unit to be inserted or removed is performed in a live state. An information processing apparatus provided with a unit device mounting board having a mounting mechanism for enabling the unit device mounting board side contact portion for connecting with a contact portion of the unit device, the contact portion for grounding, for power supply The contact is divided into three types of groups of contacts and signal contacts, and the distance from the end of the unit device mounting board to the contact tip is the ground contact,
Since the signal contacts and the power supply contacts are disposed so as to be longer in the order, the contact timing when connecting with the contact portion of the unit device is such that the ground contact, the signal contact, and the power supply The supply contacts are arranged in the order.

[0019]

Embodiments of the present invention will be described below with reference to the drawings. [First Embodiment] FIG. 1 shows a mounting mechanism for hot-swap insertion and removal according to a first embodiment.

This hot-swap mounting mechanism is realized by devising both configurations of the unit equipment 22a and the unit equipment mounting board 24a on the information processing apparatus side for mounting the unit equipment 22a. In the case of the first embodiment, the unit device 22a includes three types of connectors: a ground (hereinafter referred to as "GND") connector 31a, a signal connector 32a, and a power supply connector 33a. On the other hand, the unit equipment mounting board 24
a is also a GND connector 41a and a signal connector 42
a and a power supply connector 43a. This divides the contact part into three types of groups for GND, signal, and power supply,
The corresponding connectors 31a, 32a, 33a,
41a, 42a and 43a are connected. In addition,
Although not shown, each connector 31a, 32a, 33a, 4
1a, 42a, and 43a are provided with a plurality of contacts (electric contacts) for making an electrical connection with each other when coupled with a mating connector, respectively, and are provided with connectors 31a, 32a, and 33a on the unit device 22a side. Connectors 41a, 42 on the unit device mounting board 24a side
The corresponding parts a and 43a have a male-female configuration and can be connected to each other.

Further, in the first embodiment, by changing the arrangement positions of the GND connector 31a, the signal connector 32a, and the power supply connector 33a on the unit device 22a side, the position of the tip of the contact included in each connector is changed. However, they are adjusted so that they are shifted when viewed in the direction of insertion into the unit device mounting board 24a. Specifically, the position of the contact tip of the power supply connector 33a is
The end of the contact of the signal connector 32a is located at a predetermined distance A (> 0) from the end 25 of the board.
The contact end of the GND connector 31a is located at a predetermined distance B (> A) from the substrate end 25. That is,
The distance to the contact tip when viewed from the substrate end 25 is set to be longer in the order of power supply, signal, and GND.

On the other hand, the 3 on the unit equipment mounting board 24a side
The positions of the contacts of the three connectors 41a, 42a, 43a are all adjusted to be the same when viewed from the insertion direction of the unit device 22a. Thus, the three connectors 31a, 32a, 33a on the side of the unit device 22a.
The positions of the tips of the contacts are shifted when viewed in the direction of insertion into the unit equipment mounting board 24a, while the three connectors 41a and 42 on the unit equipment mounting board 24a side are shifted.
Since the contacts a and 43a are set to be at the same position, when the unit device 22a is mounted on the unit device mounting board 24a, the following is performed.

That is, first, the GND connector 31a of the unit equipment 22a is connected to the unit equipment mounting board 24a.
, The signal connector 32a of the unit equipment 22a is fitted to the signal connector 42a of the unit equipment mounting board 24a, and finally, the power supply connector 33a is fitted to the unit equipment mounting board 24a. It fits into the power supply connector 43a. Thereby, the contact timings of the three types of contacts can be shifted.

As described above, the contact timing of the contacts is in the order of GND → signal → power supply.
There are the following merits. (1) First, the GND contact and the power supply contact are divided, and the following advantages can be obtained by contacting the GND contact and the power supply contact in this order. In other words, the GND levels are first matched by contact with GND, and power is supplied after the levels are stabilized, so that fluctuations in the power supply voltage itself can be prevented. Also, GND
The noise on the power supply, which is likely to be generated when the power supply and power supply contacts are simultaneously connected, can be suppressed. (2) Then, since the contact is made in the order of GND contact → signal contact → power supply contact, the signal contact comes into contact before the power supply contact. Therefore, until the power is supplied. , The signal can be prevented from being disturbed by preventing the signal from being driven from the unit device side before the signal contact comes into contact.

As described above, it is possible to appropriately cope with hot-swap of the unit equipment 22a. [Second Embodiment] FIG. 2 shows a hot-swap mounting mechanism according to a second embodiment. In the first embodiment, as shown in FIG. 1, the connectors 31a, 32 on the unit device 22a side are used.
The mounting positions of the connectors 41a, 42a, and 43a on the unit device mounting board 24b are shifted as shown in FIG. It was done.

More specifically, in this case, three connectors 31b, 32b, and 33b on the unit device 22b side are used.
Is located in the unit device mounting board 2
All adjustments are the same when viewed in the direction of insertion into 4b. On the other hand, regarding the unit device mounting board 24b, the position of the contact tip of the power supply connector 43b is the same as the unit device mounting board end 45,
The tip of the contact of the signal connector 42b is located at a predetermined distance A (> 0) from the edge 45 of the unit equipment mounting board, and the tip of the contact of the GND connector 41b is located at a predetermined distance B (> A) from the edge 45 of the unit equipment mounting board. )
In the position. That is, the distance to the tip of the contact when viewed from the end of the unit device mounting board 45 is set to be longer in the order of power supply, signal, and GND.

As described above, the tips of the contacts of the three connectors 31b, 32b, 33b on the unit device 22b side are at the same position, and the unit device mounting board 24b
The contacts of the three connectors 41b, 42b, 43b on the side are set so as to be separated from the unit device mounting board end 45 in the order of power supply, signal, and GND. When mounting on the mounting board 24b, the following is performed.

That is, first, the GND connector 31b of the unit equipment 22b is connected to the unit equipment mounting board 24b.
, The signal connector 32b of the unit equipment 22b is fitted to the signal connector 42b of the unit equipment mounting board 24b, and finally, the power supply connector 33b is connected to the unit equipment mounting board 24b. It fits into the power supply connector 43b. Thereby, the contact timings of the three types of contacts can be shifted.

The effect of the second embodiment is the same as that of the first embodiment, and will not be repeated here. [Third Embodiment] FIG. 3 shows a mounting mechanism for hot-swap insertion and removal according to a third embodiment.

In the first embodiment described above, as shown in FIG. 1, the three types of contacts for the GND, signal, and power supply on the unit equipment 22a are connected to the corresponding connectors 31a, 32a, and 33a, respectively. However, in the unit device 22c of the third embodiment, card edges are mixed. Specifically, the power supply connector 33a in the first embodiment shown in FIG. 1 is replaced with a power supply contact as the power supply card edge 33c in the third embodiment. . In this case, since the contact is provided directly at the edge, the edge becomes a "plug", and the power supply connector 43c on the unit device mounting board 24c side becomes a "jack" for receiving the connector.

The power supply card edge 33c
In most cases, the contact is formed by applying a gold plating process. However, even if the pattern 134 for the gold plating process as shown in FIG. In the case of there is no problem.
In other words, in this case, since there is only one type of contact for power supply, there is no need to change the length of the contact as in the conventional case shown in FIG. Therefore, there is no particular problem even if the contact is provided by electrolytic gold plating which is advantageous in terms of resistance to contact resistance.

If the card edge 33c formed as described above is used, a corresponding connector is not required. Since the connector is basically a separate member, the card edge type reduces the number of components and eliminates the need to select a connector suitable for the unit. Further, there is an advantage that the card can be easily inserted and removed because of the shape of the card edge. [Fourth Embodiment] FIG. 4 shows a hot-line insertion / extraction mounting mechanism according to a fourth embodiment.

The fourth embodiment is a further modification of the third embodiment described above.
The three types of contacts for GND, signal, and power supply on the side are all formed by a card edge type. Therefore, in the fourth embodiment, a GND card edge 31d, a signal card edge 32d, and a power supply card edge 33d are provided. Similarly, when the fourth embodiment is attached to the unit device mounting board 24d, the power supply → signal → GND. The positions of the contacts formed on each card edge are shifted so as to make contact in the order of use. In this case, since all three types of contacts are directly provided on the edge portion, the unit device mounting board 24d
Each of the connectors 41d, 42d, 43d on the side is of a "jack" type for receiving this.

As described above, if all three types of contact portions are formed in a card edge type, a connector member is not required, and disadvantages such as an increase in the number of components and a complicated configuration and an increase in cost can be prevented. However, conversely, when a connector member is used, for example, a ground contact,
The gold plating patterns corresponding to the signal contacts and the power supply contacts are formed at the same position, and by adjusting the arrangement position of the connector itself or the position of the contact formed on the connector, as a result, three types of contacts are obtained. There is an advantage in that the arrangement position can be adjusted.

As described above, the present invention is not limited to such an embodiment, and can be implemented in various forms without departing from the gist of the present invention. For example, GND
In the first embodiment, the positions of the connectors 31a, 32a, and 33a on the unit device 22a side are shifted, and in the second embodiment, the unit device mounting Substrate 24
Although the arrangement positions of the b-side 41b, 42b, and 43b are shifted, these connectors may be shifted.

In the first to fourth embodiments,
When the connector is shown, the position of the connector itself is shifted, but this assumes that the position of the tip of the contact in the connector is set to be the same for all connectors. In other words, if the position of the connector itself is shifted, it means that the position of the tip of the contact inside the connector is also shifted. However, as described in the above description, since the contact timing between the corresponding contacts of the unit device 22a and the unit device mounting board 24b only needs to be actually shifted, for example, even if the position of the connector itself is the same, the inside of the connector is not changed. If the position of the tip of the contact is shifted, the same purpose can be achieved. However, in that case, it is necessary to adjust the length of the contacts inside the connector.

FIG. 1 shows the first to fourth embodiments.
4 to 4, it is assumed that the GND, signal, and power supply contacts are arranged in a horizontal line. However, for example, a configuration in which three contacts are arranged in a vertical direction may be assumed. Even in this case, by shifting the arrangement position of each contact, the same effect as in the above-described embodiments can be obtained.

[Brief description of the drawings]

FIG. 1 is a schematic explanatory view showing a hot-line insertion / extraction compatible mounting mechanism of a first embodiment.

FIG. 2 is a schematic explanatory view showing a hot-line insertion / extraction compatible mounting mechanism according to a second embodiment.

FIG. 3 is a schematic explanatory view showing a hot-swap mounting mechanism according to a third embodiment.

FIG. 4 is a schematic explanatory view showing a hot-swap mounting mechanism according to a fourth embodiment.

FIG. 5 is a schematic explanatory diagram showing an information processing system configured by connecting a plurality of unit devices to a unit device mounting board of the information processing device.

FIG. 6 is an explanatory view showing a conventional card edge type contact.

[Explanation of symbols]

Reference Signs List 21 information processing device 22, 22a, 22b, 22c, 22d unit equipment 23 control unit 24, 24a, 24c, 24d unit equipment mounting board 25 board end 31a, 31b, 31c ground (GND) connector 31d ... GND card edges 32a, 32b, 32c ... signal connectors 32d ... signal card edges 33a, 33b ... power supply connectors 33c, 33d ... power supply card edges 41a, 41b, 41c, 41d ... GND connectors 42a, 42b, 42c, 42d: Signal connector 43a, 43b, 43c, 43d: Power supply connector 45: Unit equipment mounting board end

Claims (7)

[Claims] In an information processing system in which a plurality of unit devices are connected to a unit device mounting board of an information processing apparatus, when the unit devices are inserted or removed, the unit devices other than the target device are placed in a live state. A mounting mechanism for allowing insertion and removal while the unit is mounted, wherein the contact portions of the unit device and the unit device mounting board are respectively divided into three types of a ground contact, a power supply contact, and a signal contact. The unit device and the unit device so that the contact timing of the contact portion when the unit device is mounted on the unit device mounting board is in the order of the ground contact, the signal contact, and the power supply contact. At least one core of the unit device mounting board Hot swap corresponding mounting mechanism arrangement position of tact portion is characterized in that it is adjusted. 2. The hot-swap mounting mechanism according to claim 1, wherein at least one of the three groups of the ground contact, the signal contact, and the power supply contact on the unit device side is provided. A hot-swap mounting mechanism characterized by being formed in a card edge type. 3. The mounting mechanism according to claim 1, wherein at least one of the three types of groups of the ground contact, the signal contact, and the power supply contact on the unit device side is at least one contact. A hot-line insertion / extraction mounting mechanism characterized by being formed by mounting a connector member. 4. When a unit device is inserted and removed in an information processing system in which a plurality of unit devices are connected to a unit device mounting board of the information processing device, unit devices other than the unit to be inserted and removed are placed in a live state. A unit device provided with a mounting mechanism for allowing insertion and removal while the unit device is mounted, wherein a unit device side contact portion for connecting to a contact portion of the unit device mounting board includes a ground contact, a power supply contact, It is divided into three types of signal contacts, and the distance from the end of the unit device to the contact tip is increased in the order of the power supply contact, the signal contact, and the ground contact. By doing so, the contact with the contact portion of the unit device mounting board Live insertion compatible module device, characterized in that the contact timing in connection at said ground contact, the signal contacts are configured such that the order of the power supply contacts. 5. The hot-swappable unit device according to claim 4, wherein at least one of the three groups of the ground contact, the signal contact, and the power supply contact is formed as a card edge type. A hot-swappable unit device. 6. The hot-swappable unit device according to claim 4, wherein at least one of the three types of groups of the ground contact, the signal contact, and the power supply contact has a connector member mounted thereon. A hot-swappable unit device characterized by being formed. 7. When inserting or removing a unit device in an information processing system in which a plurality of unit devices are connected to a unit device mounting board of the information processing apparatus, the unit device other than the unit to be inserted or removed is placed in a live state. An information processing apparatus comprising a unit device mounting board having a mounting mechanism for allowing insertion and removal while the unit device is mounted, wherein a unit device mounting board side contact portion for connecting with a contact portion of the unit device is used for grounding. The contact is divided into three types of contact, power supply contact and signal contact, and the distance from the end of the unit equipment mounting board to the contact tip is the ground contact, the signal contact, and the power supply. The arrangement in which the length of the contact Wherein the contact timing at the time of connection with the contact portion of the device is configured to be in the order of the ground contact, the signal contact, and the power supply contact. .