Inside Details - more
I started to remove the sides in an attempt to get to the main board. But it turned out that access was much simpler. All I had to do was take off the front cover, remove two tiny cross-head screws, lift off the front grill assembly (after disconnecting a cable), remove the top cover panel (the catch is accessed from inside the empty drive bay), lift the drive backplane assembly out of the connector on the main board (after turning two latches), remove two screws holding the assembly in place, then slide it out. (It's easier than it sounds).
Figure 6 shows the main board / power supply assembly, which is, again, a pretty nice piece of design.
Figure 6: Main board / power supply assembly top view
The AMD Sempron 3400+ CPU is under the large heatsink, with the heatsink-less SiS966 South Bridge and what is probably a SiS 741CX North Bridge under the smaller heatsink. Other key parts are a SiS196 handling the gigabit Ethernet port and a Marvell 88SE6111 SATA controller.
The Qimonda HYS64T64000HU-3S-B DIMM at the top edge of the board is 512MB of DDR2 PC2-5300 unbuffered RAM. It's all powered by a 200W HIPRO HP-U200EF3 supply with universal AC input. The supply slides into a pocket in the same bracket that holds the main board and is secured by three screws.
HP's documentation regarding maximum capacity has a few oddities. The MSS (EX475) came with two Seagate ST3500630AS 500 GB Barracuda 7200.10 7200 RPM SATA drives with 16MB cache and the lower-priced EX470 comes with only one 500 GB drive.
HP's data sheet says the maximum storage space is "only limited by number of hard drive bays (4) and USB ports (4)", neglecting to mention the eSATA port. Then a footnote on this HP page refers to "expansion capacity up to 6TB of storage" with asterisks noting the use of 750GB drives. So while I'd like to believe the "Maximum storage space: unlimited" spec in the MSS User's Guide, I suspect that at some point, you'll hit a maximum that won't be "unlimited".
The whole shebang drew around 55 W (with the two drives), which is on the high side of my 15 W / drive rule of thumb for NAS power consumption. In all, the MSS looks to be designed for both easy manufacture and service.
The software running the MSS is, of course, Windows Home Server, which is based on Windows Server 2003 SP2. It's not strictly a subset of Server 2003, since WHS contains some features that Server 2003 doesn't have. WHS comes set to accept Remote Desktop Connections. So if you have XP Pro or another OS that supports the Remote Desktop client, you can log in and give yourself a tour. Note that upon first login after starting up the MSS, you'll be greeted by a full-screen browser window with the warning shown in Figure 7. 'nuff said!
Figure 7: Proceed with caution
Although the MSS supports multiple drives, it does not support RAID. Instead, it uses what Microsoft calls "folder duplication" to provide enhanced file robustness. Folder Duplication lets the user select folders that get copied onto a second hard drive. But you can't control the drive used—WHS hides all that from the user.
A key advantage of Folder Duplication is allegedly more efficient use of drive space. Available space in my two-drive review system with two 500 GB drives was reported as 931.32 GB. If RAID 1 were used, I would have had only about half that shown as available, since RAID 1 copies all files. (Note that "System" use was reported as 20 GB.) But if you're not comfortable with choosing which of your files are expendable when one of the drives eventually goes belly-up, Folder Duplication won't save you any space.
Folder Duplication works with another technology called "Drive Extender" that allows addition of multiple drives—internal, USB or eSATA—of varying capacities to increase storage. The additional storage is merged into a single "folder namespace" so that you don't have to (actually, you can't) keep track of which files are stored where.
Drive Extender (DE) is definitely targeted at consumers who think RAID is something you keep under the kitchen sink and don't want to be asked to pick a mode when adding more capacity to their MSS. But if you like your storage divided into volumes and want to control how your NAS is protecting your data, then DE—and the MSS—won't be your cup of tea.