The DS409slim is not meant to be dismantled. HDDs are inserted from the outside. However, you can reach to its internals if you’ve got a strong desire and appropriate tools to do that. We don’t mind this difficulty, but it is not good that the user cannot easily access the fan for cleaning or replacement.
The NAS is built in a sturdy and simple way. It is based on a metallic frame PCBs and the plastic exterior are fastened to. Most of the electronic components are located on the main PCB. An additional PCB with HDD connectors is also employed.
On the hardware level, the NAS is based on a Marvell 88F6281 processor (codenamed Kirkwood, ARM core, 1.2GHz clock rate, without a heatsink). The system memory is one 128MB chip. A 4MB flash memory chip is used for the bootloader. The internal HDDs are connected to a Marvell 88SX7042 controller. A small card (14 x 9 centimeters) carries a few auxiliary chips like a USB hub, a LED indicators controller, etc. One of the unused connectors seems to be necessary for console access to restore firmware.
The NAS is cooled by a 60mm Evercool EC6010L12ER fan. It is located at the bottom of the device, so you should not install the latter on a soft surface. The fan is almost silent when working. Considering that 2.5-inch HDDs are generally quiet as well, this NAS will be optimal for home applications. The HDDs were never hotter than 40°C during our tests. The chips on the system PCB were up to 55°C hot.
The unipolar power supply allows installing this device into your car, for example, but a more “industrial” case would be appropriate then. This also allows powering the system up autonomously for a long time, especially as its power consumption is rather low. According to the manufacturer, the NAS needs no more than 20W under load, so it will work very long if powered by an UPS.