This Custom-Built Open Source SSD Aims to Fill the 1.8" ZIF IDE Hard Drive Gap in Vintage Computing

Vintage computing enthusiast Collin "dosdude1" Mistr has put together a board design that fills in the hole left by the departure of the 1.8" Zero Insertion Force (ZIF) IDE hard drive format — offering an open source solid-state pin-compatible alternative.

"[This is] a ZIF IDE SSD I designed myself," Mistr explains, "intended for use in any machine that utilizes a 40-pin 1.8" ZIF IDE hard disk […] such as the 2008 MacBook Air, Sony Vaio UX UMPCs, or what have you. This is a custom [board] that I designed myself, and the reason I've designed this myself is because the only alternative to something like this is a CompactFlash Card — which are ridiculous expensive, for some reason — or one of those really sketchy Chinese ZIF IDE hard drives."

The 1.8" hard drive form factor was originally developed by Integrated Peripherals and launched in 1993, as an alternative to 2.5" drives for portable PCs aiming to shrink their dimensions or cram in other components. While not as small as IBM's Microdrive, which used a one-inch disk to put a spinning platter into CompactFlash-compatible housing, it shrunk the storage footprint enough to see relatively broad adoption — right until it was abandoned in favor of 2.5" and M.2 SSDs, or for some manufacturers the even-more-space-saving alternative of soldering flash chips directly to the motherboard.

Those trying to recover a vintage machine which relies on a 1.8" drive, original models of which are failing as they reach the end of their natural lives, are stuck, then — which is where Mistr's design comes into play. Built around the Silicon Motion SM2236 flash controller, the board mimics the original ZIF IDE standard perfectly — but replaces a spinning platter with up to four 64GB NAND flash chips for a total capacity of 256GB.

There's only one real catch to the project, besides having to choose your NAND flash carefully for compatibility with the controller: "The Silicon Motion SM2236 controller pinout and implementation have been reverse-engineered from open documents and salvaged PCBs," Mistr warns, "all of which have been legally obtained. Do not expect this to be correct, check for yourself."

Those interested in building their own, and willing to check the pinout, can find the PCB design files on Mistr's GitHub repository under the reciprocal GNU General Public License 3.