Abstract: Embodiments of the invention provide a magnetic disk drive capable of reducing an area used for a preamble of each data sector to increase the storage capacity. The magnetic disk drive adopts a data-surface servo system. In one embodiment, main preambles are written on a magnetic disk at a frequency of a data clock. Each of data sectors is written with a write clock that is synchronized with a signal obtained by reading the main preamble. The data sectors include sub preambles respectively. When the data sector which has been written in this manner is read, a read clock is synchronized by use of a signal obtained by reading the main preamble, and a signal obtained by reading the sub preamble included in a data sector to be read. The bit length of the sub preamble is shorter than that of the conventional preamble that is used to independently achieve the synchronization.

Abstract: In a method of writing a reference servo signal of a hard disk drive having a spiral reference servo signal that is referred to when writing a final servo signal is written while a head is moved across a disk for a predetermined time at a target movement velocity, an actual movement velocity of the head is detected from a counter electromotive force generated in a voice coil motor that moves that head, for the predetermined time during which the spiral reference servo signal is written, and the head is controlled to maintain the target movement velocity by feeding back the detected actual movement velocity.

Abstract: A hard disk drive having an improved shock resistance includes a spindle motor mounted on a frame member, at least one data storage disk positioned on and rotatable with the spindle motor, an actuator pivotally installed on the frame member and including a slider mounted on a side thereof to move the slider to a predetermined position on the disk while the actuator swings on the frame, a ramp provided outside of the disk to support a leading end of the actuator when the slider is rested thereon, and a cover member facing the frame member from a top of the ramp, the cover member including a protrusion protruding toward at least one portion of the ramp.

Abstract: A disk device includes a driving unit and a restricting mechanism that are disposed in a housing. The driving unit moves between a withdrawal position and a driving position. The withdrawal position is separated from an outer peripheral edge of a disk that is positioned in the housing, and the driving position is where the disk is rotationally driven. When the driving unit is at the withdrawal position, the restricting mechanism restricts movement of the driving unit toward the driving position.

Abstract: A recording tape cartridge comprising: a case in which a single reel having a hub around which a recording tape is wound is rotatably accommodated; and an opening formed in the case, from which a leader member attached to the end of the recording tape is pulled out, wherein at least when the leader member is pulled out from the opening, a tape guide with which the recording tape slidably comes into contact is provided in the case, and a center of the tape guide in the width direction thereof is positioned at substantially the same height as a center of the hub in the width direction thereof as seen in side view, is provided.

Abstract: A head stack assembly (HSA) protecting member to be installed in the HSA to protect the HSA, and a method of installing the HSA in a hard disk drive (HDD) by using the HSA protecting member are provided. The HSA protecting member includes a first spacer which is interposed between front ends of a pair of suspensions on which a pair of sliders facing each other are mounted, respectively, and which projects to prevent both front ends of the suspensions from contacting each other; a pair of limiters formed above and below the first spacer, such that the front ends of the pair of suspensions can be inserted into the suspension receiving portions, respectively, to restrain the front ends of the suspensions from shaking up and down; and an installation pin formed opposite the first spacer and the limiters and inserted into the HSA.

Abstract: A hard disk drive including an end tab extending from an end portion of a suspension that supports a read/write head, and a ramp including a plurality of end tab limiters and preventing the end tab from being separated, due to an external impact, from a parking zone where the end tab is supported, and at least one assembly guide rail inclined at a predetermined angle to form an assembly guide slope that guides movement of the end tab to the parking zone. At least one end tab limiter may be connected to at least one assembly guide rail and upper and/or lower sides of the end tab limiter forms with the assembly guide slope a movement guide path to guide the movement of the end tab to the parking zone.

Abstract: A pinch roller driving mechanism for a magnetic recording/reproducing apparatus, includes a main deck mounting a shaft of a capstan motor, a sub-deck that is loaded and unloaded with respect to the main deck, a pivot lever that is pivotably mounted to the main deck and supports a pinch roller that presses a magnetic tape into contact with the capstan shaft as the sub-deck is loaded, and an association unit that pivots the pivot lever so that the pinch roller contacts the shaft when the sub-deck is loaded, and returns the pivot lever to its initial position when the sub-deck is unloaded.

Abstract: An actuator and a hard disk drive (HDD) having the same. The actuator of the HDD includes a swing arm to rotate about a pivot and having a suspension with a read/write head mounted on a front end of the swing arm to record and reproduce data , a coil-supporting portion connected to a rear end of the swing arm rotate together with the swing arm to receive voice coil motor (VCM) coil , a magnet positioned above and under the VCM coil to face each other to face the VCM coil, and at least one swing-arm protrusion formed at the rear end of the swing arm to protrude toward the magnet and including a magnetic material so that a bias torque is produced due to an interaction between the at least one swing-arm protrusion and the magnet.

Abstract: A magnetoresistance effect element comprises a magnetoresistance effect film and a pair of electrode. The magnetoresistance effect film having a first magnetic layer whose direction of magnetization is substantially pinned in one direction; a second magnetic layer whose direction of magnetization changes in response to an external magnetic field; a nonmagnetic intermediate layer located between the first and second magnetic layers; and a film provided in the first magnetic layer, in the second magnetic layer, at a interface between the first magnetic layer and the nonmagnetic intermediate layer, and/or at a interface between the second magnetic layer and the nonmagnetic intermediate layer, the film having a thickness not larger than 3 nanometers, and the film has as least one selected from the group consisting of nitride, oxinitride, phosphide, and fluoride.

Abstract: Methods and apparatus provide a magnetic head that includes a magnetoresistive read sensor disposed between a first magnetic shield and a second magnetic shield. The second magnetic shield is configured to reduce effects on the read sensor due to unevenness in a topography of the read sensor.

Abstract: A magnetic head having non-GMR shunt for perpendicular recording and method for making magnetic head having non-GMR shunt for perpendicular recording is disclosed. A shunt is provided for shunting charge from a read sensor. The shunt is formed co-planar with the read sensor and is fabricated using non-GMR materials.

Abstract: A current perpendicular to plane (CPP) sensor and method of manufacturing such a sensor that prevents current shunting at the sides of the barrier/spacer layer due to redeposited material. A first ion mill is performed to remove at least the free layer. A quick glancing ion mill can be performed to remove the small amount of redep that may have accumulated on the sides of the free layer and barrier/spacer layer. Then an insulation layer is deposited to protect the sides of the free layer/barrier layer during subsequent manufacturing which can include further ion milling to define the rest of the sensor and another glancing ion mill to remove the redep formed by the further ion milling. This results in a sensor having no current shunting at the sides of the sensor and having no damage to the sensor layers.

Abstract: A drive circuit for a semiconductor switching element includes a transformer, first and second driver circuits, and a rectifier element. The drive circuit produces a drive signal based on an input signal. The transformer havs a primary winding and a secondary winding, and is integrated in a first semiconductor body. The first driver circuit is coupled to receive the input signal, and has at least one output which is coupled to the primary winding of the transformer. The first driver circuit also includes a first supply input connected to receive a first supply potential. The second driver circuit is operable to provide the drive signal and has at least one input coupled to the secondary winding. The second driver circuit has a second supply input. The rectifier element is connected between the first and the second supply input, and is integrated in the first semiconductor body.

Abstract: A ground-fault circuit-interrupter method and system for three-phase electrical power systems including a plurality of GFCI units and a processor forming a ground-fault circuit interrupting system for use in a three-phase power distribution network including a three-phase source of electrical power, a three- or four-wire main circuit, and a plurality of three- or four-wire feeder circuits connected across the main circuit. A GFCI unit is provided in the main circuit and in each of the feeder circuits. The processor is programmed to continuously monitor the main GFCI unit and each feeder GFCI unit to determine when and where a fault has occurred and, in response thereto, to interrupt the faulted circuit and to inhibit tripping of the non-faulted circuits. The novel GFCI system is applicable for solidly-grounded, resistance-grounded, or ungrounded as well as other three-phase systems.

Abstract: An electrostatic discharge (ESD) protection apparatus for programmable device is provided. This ESD protection device provides a high impedance along the electrical path from the pad to the power system for preventing the programmable device from damages induced by ESD event; and the impedance can be intentionally decreased during the normal reading and writing operations.

Abstract: An apparatus for providing electrostatic discharge protection includes a first conductive trace and a second conductive trace. The first conductive trace defines a first conductive periphery and is deposited on a first surface. The second conductive trace defines a second conductive periphery and is deposited on a second surface. The second surface is spaced apart from the first surface by a gap distance and in parallel relation so that a spark gap is defined by the gap distance between the first conductive periphery and the second conductive periphery.

Abstract: A power control system with a pseudo-power up, an aircraft including the power control system and a method of controlling power in an aircraft. On-board wiring is protected from faults by electronic circuit breakers (ECBs), which may also control AC/DC electrical power supplies of on-board electrical/electronic equipment. A computer processor operating a user interface, e.g., a graphical user interface (GUI), through a display. An on-board store stores the GUI, other computer applications and the current state of each ECB, e.g., in a breaker state table. In a pseudo-power mode up, the stored circuit breaker state is available without providing power to the ECBs and, correspondingly to the coupled on-board electrical systems. When terminated, the system can power off, or proceed to normal power where each ECB is configured according to the breaker state table prior to providing power to protected systems.

Abstract: A power supply control circuit is disclosed. The power supply control circuit controls a current which is supplied from a power source to a load. The power supply control circuit includes a reverse current detecting circuit which detects a reverse current flowing from the load to the power source and a reverse current preventing circuit which disconnects a line between the power source and the load when the reverse current is detected by the reverse current detecting circuit.

Abstract: An electrical receptacle including a housing having an inwardly directed side and an electrical resistor thermally coupled to the inwardly directed side of the housing.

Abstract: An in-line surge suppressor having a body with a bore between two ends and at least one channel located within the body and around the bore. An inner conductor is located within the bore. A shorting element has a plurality of segments that extend from the inner conductor, through extension grooves between the channel and the bore, into a common or separate channel(s). The segments coupled to the channel(s), proximate a distal end of each segment.

Abstract: An object is to provide a light emitting device capable of efficiently dissipating heat generated in a semiconductor light-emitting element.

Abstract: A pair of back-to-back-coupled zener diodes is coupled from the input to the output of each leg of a common mode choke used in a LC circuit for reducing EMI into the power supply of an electrical device. The reversed biased zener diode of each pair breaks down when ringing voltage amplitude resulting from a voltage surge applied at the inputs of the common mode choke exceeds the breakdown threshold voltage of the zener diode. Transorb devices may be substituted for the back-to-back-coupled diode pairs.

Abstract: An ionizer incorporated with an electronic appliance utilizes the power supply of the appliance so that only less device and space are required for the additional ion function. The small power-consumption ionizer does not influence the original function of the electronic device while the negative ions help refreshing the air and improving people's moods, energy and health.

Abstract: A dissipator useful for discharging provides a continuously variable high-voltage load under control of a computer or other device capable of providing an analog control voltage. Known dissipator arrangements use multiple high voltage switches and resistors to attempt to dissipate power. However, the disclosed dissipator uses the resistive property of a matrix of photo resistive cells, typically cadmium sulphide arranged on a circuit board. These photo resistive cells are series connected and controlled optically to vary their resistances. An optical control signal is provided for each photo resistive cell by a corresponding light emitting diode (LED). The amount of light emitted by each LED is analog controlled.

Abstract: An apparatus for interfering whith locomotion by a target includes a processing circuit, a signal generator, and a transmitter. The processing circuit determines an identification of the apparatus and an identification of a user of the appararatus. The signal generator is controlled by the processing circuit. The signal generator provides a current for passing through the target to produce eskeletal muscle contractions in the target that interfere with locomotion by the target. The transmitter is coupled to the processing circuit. The transmitter transmits a description of a use of the apparatus.

Abstract: Another apparatous, according to various aspects of the present invention, produces contraction in skeltal muscles of a target to impede locomotion by the target. The apparatus is used with a provided deployment unit that deploys an electrode away from the apparatus. The electrode conducts a current through the target. The apparatus includes a terminal; producing sub-system for producing an electric arc to warn the target without conducting a current through the target; conducting sub-system for conducting the current in series through the terminal and through the target; initiating sub-system for inititaing deployment of the electrode; and an operator interface. The operator interface further facilitates, prior to deployment of the electrode, repeated operation of any one or both of the producing sub-system and the conducting sub-system.

Abstract: A plasma reactor for processing a workpiece includes a reactor chamber, an electrostatic chuck within the chamber having a top surface for supporting a workpiece and having indentations in the top surface that form enclosed gas flow channels whenever covered by a workpiece resting on the top surface. The reactor further includes thermal control apparatus thermally coupled to the electrostatic chuck, an RF plasma bias power generator coupled to apply RF power to the electrostatic chuck, a pressurized gas supply of a thermally conductive gas, a controllable gas valve coupling the pressurized gas supply to the indentations to facilitate filling the channels with the thermally conductive gas for heat transfer between a backside of a workpiece and the electrostatic chuck at a heat transfer rate that is a function of the pressure against the backside of the workpiece of the thermally conductive gas.

Abstract: A plasma reactor for processing a workpiece includes a reactor chamber, an electrostatic chuck within the chamber for supporting a workpiece, an RF plasma bias power generator coupled to apply RF power to the electrostatic chuck and a refrigeration loop having an evaporator inside the electrostatic chuck with a refrigerant inlet and a refrigerant outlet. Preferably, the evaporator includes a meandering passageway distributed in a plane beneath a top surface of the electrostatic chuck. Preferably, refrigerant within the evaporator is apportioned between a vapor phase and a liquid phase. As a result, heat transfer between the electrostatic chuck and the refrigerant within the evaporator is a constant-temperature process. This feature improves uniformity of temperature distribution across a diameter of the electrostatic chuck.

Abstract: In a plasma reactor having an electrostatic chuck with an electrostatic chuck top surface for supporting a workpiece, thermal transfer medium flow channels in the interior of the electrostatic chuck, a method for controlling temperature of the workpiece during plasma processing includes circulating thermal transfer medium through the thermal transfer medium flow passages and supplying a thermally conductive gas between the workpiece and the electrostatic chuck top surface, and changing thermal transfer medium thermal conditions of thermal transfer medium flowing in the thermal transfer medium flow channels so as to change the temperature of the electrostatic chuck at a first rate limited by the thermal mass of the electrostatic chuck. The method further includes changing the backside gas pressure of the thermally conductive gas so as to change the temperature of the workpiece at a second rate faster than the first rate.

Abstract: A method of manufacturing a thin film capacitor includes steps of: performing recrystallization heat treatment on a metal foil; forming a dielectric layer on a top surface of the recrystallized metal foil; heat treating the metal foil and the dielectric layer; and forming an upper electrode on a top surface of the heat-treated dielectric layer. The recrystallization heat treatment prevents the oxidation of a metal foil, by which a dielectric layer can be heat treated at a high temperature, thereby improving electric properties of a thin film capacitor and the reliability of a product.

Abstract: In an electric double layer capacitor including two plate-like polarizable electrodes stacked in layers via a separator and constituted by housing these in an outer packaging member, a contact area between a first polarizable electrode and the separator is different from a contact area between a second polarizable electrode and the separator, and the polarizable electrode with a smaller contact area is formed thicker than the polarizable electrode with a larger contact area. In addition, it is preferable that the first polarizable electrode and the second polarizable electrode have a generally equal volume.

Abstract: Active electrode material, such as fibrillized blend of activated carbon, polymer, and conductive carbon, is pretreated by immersion in a sealing coating. After the active electrode material is dried, the coating seals micropores of the activated carbon or another porous material, thus preventing exposure of water molecules or other impurities trapped in the micropores to outside agents. At the same time, the sealing coating does not seal most mesapores of the porous material, allowing exposure of the mesapores' surface area to the outside agents. The pretreated active electrode material is used for making electrodes or electrode assemblies of electrical energy storage devices. For example, the electrodes may be immersed in an electrolyte to construct electrochemical double layer capacitors. Pretreatment with the sealing coating reduces the number of water molecules interacting with the electrolyte, enhancing the breakdown voltage of the capacitors.

Abstract: The present invention provides an electrolytic capacitor manufacturing method capable of manufacturing an electrolytic capacitor having the PTC function as easy as possible. A main electrode layer in a cathode is formed so as to have the PTC function. Different from a conventional electrolytic capacitor manufacturing method of connecting a PTC thermistor to a capacitor element to give the PTC function to an electrolytic capacitor so that an electrolytic capacitor manufacturing process is complicated and the number of manufacturing processes is increased by the amount corresponding to the PTC thermistor connecting process, the process of connecting the PTC thermistor to the capacitor element is unnecessary. Consequently, complication of the electrolytic capacitor manufacturing process and increase in the number of manufacturing processes caused by the PTC thermistor connecting process can be prevented.

Abstract: A solid electrolytic capacitor includes a capacitor element 2, an anode lead terminal 3 electrically connected to an anode of the capacitor element, a cathode lead terminal 4 electrically connected to a cathode of the capacitor element, and a package 5 which is made of synthetic resin and hermetically seals the capacitor element. The lead terminals are embedded in the bottom 5a of the package with the lower surfaces of the lead terminals exposed at the bottom surface of the package. The anode lead terminal and the cathode lead terminal are respectively formed with standing pieces 8 and 9 at portions corresponding to side surfaces 5b, 5c of the package, and the standing pieces have respective outer surfaces exposed at the side surfaces of the package. This structure enhances the soldering strength and facilitates the visual inspection of the quality of the soldering.

Abstract: An assembly of devices including at least one switchgear cabinet and a cooling device. The switchgear cabinet has a closed interior, in which electric installations can be housed. The cooling device is attached in the vicinity of or near a lateral surface of the switchgear cabinet that runs vertically with respect to the front face, extending at least over part of the height of the switchgear cabinet and having a spatial connection with the interior via at least one air inlet and at least one vent outlet. The cooling device includes a receiving chamber that houses at least one heat exchanger. This invention facilitates the adaptation of the cooling device in superstructures of this type to modified cooling requirements. To achieve this, at least sections of the receiving chamber of the cooling device are divided into two or more receiving sub-chambers that are situated one above the other and a cooling module is housed in at least one of the receiving sub-chambers.

Abstract: A computing device housing is provided having a front face and a back face. Each of the front face and the back face extend lengthwise in a first axial direction and widthwise in a second axial direction. A peripheral recess is formed in the front face to extend along at least one of a lengthwise perimeter portion or a widthwise perimeter portion.

Abstract: According to one embodiment, an electronic device includes: a main body; a display device including an inputting unit; a hinge mechanism that joints the main body and the display device; and a projection portion projecting from the main body. The hinge mechanism includes a turning axis that allows the display device to turn on a turning axial line arranged along one side of the display device, and a swinging axis that allows the display device to swing together with the turning axis on an axial line arranged in a direction that intersects with the turning axis. The projection portion interferes with the display device when the display device is swung on the swinging axis in the state that the display device is overlaid on the main body.

Abstract: A fixing mechanism for fixing a disc drive and a locking device thereof solves the inconvenience involved in fixing and disassembling the disc drive. The disc drive has at least one a pair of protrusions located at side walls of the disc drive. The fixing mechanism includes a fixing frame and a locking device. The fixing frame has a pair of assembling walls and at least one receiving space is used for receiving the disc drive. One of the assembling walls has a pair of assembling boards protruding outward and an open sliding slot. The protrusions are slidably installed in the sliding slot. The locking device includes a base part and a locking arm. Two sides of the base part are assembled to the assembling boards. A locking hole formed at the free end of the locking arm correspondingly locks one of the protrusions of the disc drive.

Abstract: A power supply unit (PSU) has walls which define an internal volume of the PSU. A metal sheet forming left and right side walls and an upper wall is provided with plural perforations on each of those walls. The perforations are circular in shape, and formed in a regular grid pattern. The perforations are formed by punching the metal sheet before it is bent into shape. The perforations in the housing of the PSU allow hotspots to be carried through the walls of the housing of the PSU, following which the hotspots are unable to damage internal components of the PSU. This allows the use of reduced flow rate fans.

Abstract: A personal computer (electronic apparatus) (1) is equipped with a plurality of heat generating devices: a power source unit (11), a CPU (12), an FD drive device (13), a CD/DVD drive device (14), and an LCD (15), and a cooling fan (16) for cooling the plurality of heat generating devices (11) through (15). The plurality of heat generating devices (11) through (15) are arranged in parallel in a direction Y which crosses a central axis (16c) of an impeller (16b) of the cooling fan (16). Further, the heat generating devices (11) through (15) are arranged within a blowing range (21) of the cooling fan (16).

Abstract: A computer system includes a rack, a computer module and an interface-dedicated module to be mounted therein, and an intra-rack management module. The rack has a rear panel for power supply to and signal connection among modules, and the modules permit plug-in mounting onto the rear panel of the rack. The computer module has behind the computer a dedicated adapter which makes possible plug-in mounting of the computer onto the rack and coordinates signals between the computer and the rear panel.

Abstract: A circuit substrate includes a first rigid substrate having a plurality of land portions located at a predetermined interval on one surface, a second rigid substrate having a plurality of second land portions located at a predetermined interval on one surface and a flexible wiring board sandwiched by the first and second rigid substrates and which has a plurality of third land portions corresponding to the first land portions on one surface and a plurality of fourth land portions corresponding to the second land portions on the other surface. In this circuit substrate, the second and fourth land portions are displaced from each other relative to the first and third land portions and at least part of the first and third land portions and at least part of the second and fourth land portions are electrically connected to each other, respectively.

Abstract: The device includes a housing, a printed circuit board, a first optical subassembly, a second optical subassembly, and a lever. The device is pluggable to a host structure. The housing has a channel and ground spring fingers. The printed circuit board has contact traces and is mounted to the housing. The first and second optical subassemblies are mounted to the printed circuit board. The lever is rotatably mounted to the housing. The lever includes a rotatably mounted portion, a free end, and an actuation surface for actuation by a user. The free end of the lever forms a hook. In a locked position of the device to the host structure, the ground spring fingers contact and make electrical contact with a faceplate of the host structure, and the hook engages a slot of a circuit board of the host structure.

Abstract: A circuit board module includes a circuit board defining a top side, a bottom side and holes extending through the circuit board between the top and bottom sides. The module further includes a component mounted to a portion of the circuit board, and an EMI shield assembly configured to provide EMI shielding on the circuit board. The EMI shield assembly includes a top shield and a bottom shield. The top and bottom shields are configured to substantially enclose the portion of the circuit board and the component to provide EMI shielding when (i) contacts of the top shield insert into the holes defined by the circuit board in a first direction from the top side toward the bottom side, and (ii) contacts of the bottom shield simultaneously insert into the same holes defined by the circuit board in a second direction from the bottom side toward the top side.

Abstract: A composite electronic component includes a multilayer wiring block having a plurality of insulating layers and a wiring pattern, and a chip-type electronic component built-in multilayer block having a plurality of insulating payers and a wiring pattern and including a first chip-type electronic component. The multilayer wiring block and the chip-type electronic component built-in multilayer block are electrically interconnected and arranged on substantially the same plane.

Abstract: In accordance with one example of the disclosed subject matter, a semiconductor device can include the following features. A first lead frame can be provided that has one end configured to form a recess. An LED chip can be mounted on an inner bottom surface of the recess. A bonding wire has one end connected to an electrode on the LED chip. A second lead frame has one end connected to the other end of the bonding wire. The LED chip and the bonding wire can be sealed in a sealing resin. The first lead frame and the second lead frame can protrude from the sealing resin and can be bent around to the bottom of the sealing resin. A groove formed through the center of the bottom of the sealing resin at least partly exposes an outer circumferential surface and an outer bottom surface of the recess from the sealing resin and into the groove.

Abstract: An electronic component packaging structure, includes: circuit boards each having a wiring at least on a surface thereof; and an electronic component package secured between the circuit boards. The electronic component package includes at least one electronic component embedded within an electrical insulating encapsulation resin molded member made of an inorganic filler and a resin, the at least one electronic component being selected from an active component and a passive component, protruding electrodes are arranged on both faces of the electrical insulating encapsulation resin molded member, and the electronic component is connected electrically with at least a part of the protruding electrodes. This configuration allows circuit boards to be connected with each other and a high-density and high-performance structure.

Abstract: An enclosure for an input-output (IO) subsystem comprises: a backplane; a plurality of first slots for accepting corresponding IO option modules; a second slot for accepting an IO controller module; a plurality of first connectors corresponding to the plurality of first slots for connecting the corresponding IO option modules to the backplane; a second connector corresponding to the second slot for connecting the IO controller module to the backplane; and wherein the backplane includes communication links for interconnecting the second connector to each of the plurality of first connectors.

Abstract: An exemplary mounting apparatus for aiding in mounting a plurality of long expansion cards in electrical devices includes a locating member, and a retention member rotatably attached to the locating member. The locating member includes a base wall, a pair of sidewalls, and a top wall. Pairs of guiding rails extend from the base wall for slidably receiving ends of the expansion cards opposite to ends with cover plates. Two pairs of first positioning blocks extend from the top wall. The retention member includes a base plate, a pair of flanges, and a pair of resilient arms. A plurality of retaining tabs extends from the base plate to abut against top edges of the expansion cards. The flanges are rotatably attached to the sidewalls of the locating member. The resilient arms each include a pair of second positioning blocks for engaging with the first positioning blocks of the locating member.