In a prior art server which is configured as a RAID (Redundant Array of Inexpensice Disks) and equipped with a plurality of HDD (Hard Disc Drive) units including a fixed disk, for example an AV (Audio Visual) server, the following construction is employed so that an HDD unit can be replaced during operation of an HDD rack having the HDD unit.
In the vicinity of the HDD (Hard Disk Drive) rack having therein an HDD unit of an HDD main body including a fixed disk and a control board, and a frame-shaped caddy attached to the HDD main body, there are provided an I/F rack having therein an interface board, an MB (Main Board) rack having therein a main board connected to the I/F rack, and a motherboard connected therewith. One side of the HDD rack has an opening, and the HDD unit is insertable laterally into the HDD rack.
The frame-shaped caddy of the HDD unit is supported in the HDD rack. The HDD rack has a fitting hole at a predetermined position, and the frame-shaped caddy of the HDD unit has a projection to be fit in the fitting hole. When the frame-shaped caddy is inserted in the box-shaped rack, the projection fits in the fitting hole, so that the frame-shaped caddy is positioned and fixed.
A method in a conventional example for fixedly arranging a plurality of HDD units in parallel in an HDD rack employs a sheet metal structure which has a length equaling the total length in the parallel arrangement direction of the HDD units, and which is designed to press the HDD units. However, this method is problematical in that HDD units cannot be replaced individually.
Moreover, in inserting or removing an HDD unit by gripping a part of the frame-shaped caddy, the HDD unit to be inserted from the lateral direction into an HDD rack is difficult to hold. It is also hard to immediately find where to hold the HDD unit.
Additionally in the conventional AV server and the HDD apparatus, the HDD main body is attached to the box-shaped caddy, and the above-mentioned IF rack and MB rack are placed in an upright posture, so that the flow of cooling air along the surfaces of HDD main body is insufficient to prevent heat deterioration of electronic components.
In an operation of inserting an HDD unit into the HDD rack, the caddy of the HDD unit remains free until engagement of the projection of the caddy with the fitting hole of the HDD rack. Therefore, there is a danger of damage to the HDD main body due to impact.
An HDD unit, when not firmly fixed, is liable to undergo self-vibration and cause errors by failing to read data due to vibration of a head. To meet this, the conventional HDD rack is arranged to increase the weight of the caddy or press the caddy with a spring. However, these measures increases the mass of the whole apparatus and complicates the structure.
The use of a flat cable or the like for connection between an HDD rack and an I/F poses further problems. The cable, which is rigid and inflexible, tends to increase the difficulty in installation, assemblage and maintenance. There is a further problem that a connector for the flat cable can be disconnected after assembling by a restoring force of a bent or twisted portion of the cable.
Furthermore, the flat cable can cause disk errors under the influence of noise.