By Collin Allen

Rackmount G4

April 8, 2008

I took a trip out to my previous employer’s business to check out an interesting find he stumbled upon in a purchased lot of computer equipment. Among other official Apple-branded machines and workstations were several apparently custom built 3U rackmount G4 servers.

g4_front

I took a bunch of pictures documenting the meticulous overhauls that were done in readying the new machines for about 8 hard drives, plenty of PCI cards, and proper cooling. Judging by the labels left on the converted towers, they were intended to be used as ProTools workhorses, mixing audio and piping effects around someone’s once-elaborate pro audio setup. Aside from the unique form factor (for a Mac-based server, anyway) and the sheer geekiness of such an undertaking, the power controls and cooling system are of particular interest.

g4_top

The one really interesting bit of circuitry in the whole system is one tiny Marathon power board, which connects to the relocated front panel board of the original tower. Several years ago, Marathon Computer offered rackmount conversion kits for Apple’s G3, G4, and even iMac systems. These enclosures appear to be made by I-Star, despite similarities to Marathon’s PowerRack kit, though pictures and documentation about Marathon’s kits are now extremely hard to find.

To keep the system and its veritable wall of hard drives running cool and trouble-free, large fans were employed in conjunction with a simple, off-the-shelf fan controller which combines the feedback from multiple fans into one monitoring port, complete with overheating alarm and adjustable temperature settings (via jumpers).

For completeness, a SCSI card and stealth serial port were added, leaving room for ProTools PCI audio cards. In its day, this was a screaming system that bested even Apple’s top PowerMac offerings. Someone clearly spent many hours getting the physical layout and electrical systems just right, which I thought was worth preserving and sharing.