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Assembly Instructions

Assembly Instructions

Assembling LittleFe from a parts kit requires only basic knowledge of handtools and computer components. You will need large and small flat and Philips screwdrivers, pliers and cable ties to complete the assembly. Most people budget a full day to do a complete assembly, test, and software installation. With practice, it has been shown that if nothing goes wrong, a single unit can be assembled in about 4 hours.


Assembling LittleFe consists of the following steps:

  1. Assembling the frame and rails
  2. Mounting the regulated 110/240 VAC power supply to the frame
  3. Mounting the network switch and installing the network cabling
  4. Mounting the mainboards to the cards
  5. Mounting the power supplies and switches to the mainboards
  6. Installing the up-link NIC on the head-node
  7. Installing the mainboards in the cage
  8. Cabling the power supplies
  9. Mounting the disk drive and CD/DVD drive to the frame and installing the power and data cables
  10. Plugging in the monitor, keyboard, and mouse
  11. Performing the initial power-up tests
  12. Configuring the BIOS on 5 of the mainboards to boot via the LAN and PXE

Hardware Assembly


The frame is assembled from the rails, card-edge guides, and end plates.

Rails, card-edge guides, and end plates. Note that only one of the end plates is prepped for the 110/220VAC line input switch and the shorter spacing between the holes in the rails and the end of the rails at the bottom of the picture.

The rails and card-edge guides are assembled first. Layout the rails on a table lining-up the holes so that the ends with the shorter hole spacing are together and to the right. Lay the card-edge guides on top of the rails so that the large hole is facing away from you.

Assembly of the first set of rails and card-edge guides. Note the shorter hole spacing to the right, the 110/220VAC regulated power supply mounting bracket, and the larger holes at the bottom of the fourth card-edge guide from the left.

Using the flat-head screws and nylon lock nuts mount the card-edge guides to the rails. The bracket which holds the regulated power supply should be placed on the left end of one assembly with the right-most mounting hole on the fourth card-edge bracket from the left. Two of the the card-edge guides have larger holes at the bottom, these should be placed fourth from the left (this is where the cross-tie bar goes). Before tightening the screws be sure the rails are aligned properly, the easiest way to do this is to use a carpenter's square.

The second rail card-edge assembly is a mirror image of the first, that is the short spacing would be to the left on the table as you assemble it. This ensures that when combined with the end plates that the card-edge guides face each other.

Assembly of the second set of rails and card-edge guides. Note the shorter hole spacing to the left and the absence of the 110/220VAC regulated power supply mounting bracket.

Next mount the card-edge supports to each card-edge guides, these go in the large hole in the bottom of each card-edge guide, with the threaded end facing out, and are secured with nylon lock nuts. The fourth card-edge from the left on each rail set is for the cross-tie bar.

Card-edge supports and the cross-tie bar mounted to the card-edge guides.

Next the end plates are assembled. This consists of mounting the rubber feet on the top and bottom and mounting the 110/220VAC line input switch. The smaller rubber feet go on the top and the larger feet on the bottom. The line input switch mounts with two screws, make sure that the switch is mounted such that it's accessible from the outside of the frame.

End plate showing placement of small and large rubber feet.

End plate showing placement of 110/220VAC line input switch.

Now that the rail/card-edge assemblies and end plates are complete the frame can be assembled. Note that the end-plate with the 110/220VAC line input switch should be attached to the end of the rails with the longer hole spacing.

Completed end plate and rail assemblies.

The frame is now ready for the installation of the high voltage wiring, low voltage wiring, and 110/220VAC regulated power supply.


The 110/220VAC regulated power supply is mounted to the bracket with two screws and lock washers. The end with the connection block should face to the right as you look at the frame from the outside. The 110/220VAC power supply cable should be attached to the line input switch and then to the marked terminal locations on the regulated power supply. Take care to insure that load (white), neutral (black), and ground (green) are all properly connected. Routing and securing the 110/220VAC feed line can be seen in the picture below.

110/220VAC regulated power supply mounting.

110/220VAC regulated power supply connection block showing ground, neutral, and load lugs (the three on the far right).

Routing and mounting the 110/220VAC feed line.


The network switch should be mounted to the card with the indicator lights facing up and the network connections facing down. Before inserting the network card into the frame the network jumpers should be installed starting with port 1, note that the cables are numbered, lf0 should go to port 1, lf1 to port 2, etc.

Network switch mounted to the plate with the first two network jumpers installed.

Place the network card in the frame routing the cables underneath the rails in preparation for securing them to the rails as illustrated below. Secure the cables to each rail as shown in the picture below with nylon cable ties. Take care to ensure that the network jumpers each have a smooth path with no sharp bends or kinks.

Routing the network jumpers.

Securing the network jumpers.

CPU and Disk Cards

The mainboards are mounted to the cards using bolts, 1/8" nylon spacers, and nylon lock nuts. The nuts should go on the card side, the bolt heads on the mainboard side. The corner opposite the power supply connector uses a 1/16" nylon spacer and flat metal washer in conjunction with the angle bracket, this provides a mount for 12VDC input connector. Note that the nylon spacer should be in contact with the mainboard, then the angle bracket, then the flat metal washer which is in contact with the card.

The angle bracket which holds the 12VDC input feed is highlighted with a green laser on the left-hand side of the picture.

Once the mainboard is mounted to the card the on-board ATX power supply can be inserted into the mainboard connector and the 12VDC input connector can be mounted to the angle bracket.

The on-board ATX power supply is highlighted on the right with a green laser, the 12VDC input connector is on the left in the bracket.

The power switch is mounted with a single screw and nylon lock nut to the top of the audio out/PS2 block on the front of the mainboard. The wires are routed around the heat sink and then the connectors are placed onto the header pins located on the back of the mainboard near the angle bracket.

The power switch mounted on top of the audio/PS2 block.

Overhead view showing the routing of the power switch cables to the header pins located in the upper right-hand corner of the board near the 12VDC input connector.

The connectors from the power switch are labeled power switch, HDD LED, reset switch, etc.. See the mainboard manual for a pin-out of the header to which they are connected.

The uplink NIC uses the PCI bus connector on the head-node's mainboard. After removing the RJ-45 socket bezel from the card install it. A very small cable tie can be used to secure the card from wiggling free of the PCI connector.

Cable management is done using nylon cable ties. Re-usable cable ties, i.e. ones with a release tab, facilitate easy dissassembly and reassembly which in turn makes it possible to use LittleFe to show students the inner workings of a computational system. The extra Molex connectors are secured along the side of the mainboard with one cable tie on each mounting screw. The wires for the power switch are included in the bundle at the rear of the board.

Detail showing the cable management for the Molex connectors on the side of the mainboard.

Once the on-board ATX power supplies and power switches are mounted the five compute mainboard cards can be installed in the frame.

The five compute mainboard cards installed in the frame.

The CD/DVD drive and disk drive are mounted to the drive card using O rings as illustrated below. Note the orientation of the drives, this is important for the cabling between the drive card and the head node mainboard card.

The CD/DVD drive, disk drive, and disk card with the O rings mounted on it.

The drives mounted on the disk card.

Install the drive cables to the drives and then to the head-node mainboard as illustrated below.

Drive and power cabling for the disk drive card.

Once the drive card has been assembled and cabled to the head-node mainboard those two cards can be installed in the frame as illustrated below.

Installing the head node mainboard card and disk card into the frame. Note the orientation of the disk card.

BIOS Configuration

The five compute nodes should have their BIOSs configured to boot over the LAN using PXE. The head-node BIOS should be set to boot from the IDE disk first and CD/DVD second. For testing and debugging purposes all of the compute node BIOSs should be set to boot from CD/DVD second.


A basic test of the system can be performed by booting from an ISO such as the BBCD. While this only tests the head node is does ensure that the disk subsystem is functioning correctly and prepares us for installing the BCCD in the next section. If you have access to a USB CD/DVD drive you can test each of the compute nodes in a similar fashion.

Traveling Case

The system is shock-mounted in a Pelican 1610 traveling case using a two-part rubber cup and plug system. The cups are mounted on the floor and lid of the Pelican case. The plugs are mounted on the top and bottom of each frame's end-plates. When you place the frame in the case the plugs nestle in the cups on the floor. When the lid is closed those cups encase the plugs on top. This gives the system support and shock resistance in each direction. We have tested this system extensively both in field trials and by examining the results of approximately 25 commercial flights where LittleFe travelled as checked baggage. While there is occasional distortion of an end-plate if an excessive amount of baggage is placed on top of the Pelican case, on the whole the system appears to function adequately.

In terms of overall weight, LittleFe, traveling case, and any accessories, can be no more than 50lbs. This is the maximum allowed by airlines before heavy baggage surcharges apply. Practically, it is also about the maximum amount that most people can safely maneuver around an airport or school building. One advantage of the Pelican 1610 is that is has built-in wheels and a retractable handle.

Software Installation

LittleFe runs the Bootable Cluster CD (BCCD) software distribution. Complete instructions for installing it can be found at the BCCD website,


A demonstration of LittleFe at the Oklahoma Supercomputing Symposium in 2006. That's Dan Atkins with the purple tie, (now former) Director of Cyberinfrastructure at the NSF.