StealthMac: 2 Hardware Solutions for Mac OS X on Windows PCs

Our friends in Cupertino are at it again, according to our MacMole. This time Apple is finding new ways to get Macs into the workplace almost invisibly.

The StealthMac project has been ongoing for years - possibly even before Steve Jobs' return to Apple in late 1996. The team has taken different approaches over the years. Eight years ago, the big idea was to repackage existing Power Macs in boring beige cases that would look like run-of-the-mill Windows PCs.

Earliest Efforts

There are rumors of PowerPC 603e-based prototypes from 1996 or so that included a 133 MHz CPU, 8 MB of RAM (expandable to 4 MB), an unnamed video chip with graphics support to 1024 x 768, and an IDE controller, since it required a Macintosh HFS+ partitioned hard drive. The back of the card had several ports: VGA, audio in and out, ethernet, ADB, and Mac serial.

As with most DOS cards for the Mac, there was also a hydra video cable that connected to both the PC's VGA port and the StealthMac's VGA port. A similar cable was used for sound, and an internal IDE cable went to a dedicated Mac hard drive. Some later prototypes could use a notebook drive mounted directly to the StealthMac card.

These cards included stealth software that could run under Windows 3.1 or 95 to intercept keyboard and mouse input, determining whether keystrokes and mouse clicks should go to Windows or the Mac. A similar program allowed the StealthMac to read high-density Mac floppies in the PC's floppy drive. All in all, it was a very clever hack - and a bit of a kludge.

Another Direction

With the advent of the G3 CPU, Apple needed bigger heat sinks and put PCI card designs on the back burner. The new direction was building a complete Macintosh that could fit in a standard 5.25" drive bay. By tapping power directly from the PC's power supply, the Mac-in-a-drive-bay had access to more power than a PCI slot normally provided.

It would be more correct to call this one a Stealth iMac, as it used almost exactly the same components as the original iMac. The CPU was clocked down to 166 MHz to avoid heat problems, and the USB ports were hidden behind what looked like a typical CD-ROM drive door.

Instead of external audio and video cables, the new design used a small PCI host adapter to channel the Mac's audio and video through the PC's hardware.

By this time Apple had come up with partitioning software and drivers that allowed the StealthMac to access a dedicated HFS+ partition on the host PC's hard drive. However, this tended to wreak havoc with the Windows installation. As before, it was easier to use a dedicated Mac hard drive - or at least install the StealthMac before installing Windows, which in many ways made adding StealthMac to an existing PC more trouble than it was worth.

At least it was possible to handle all I/O through Windows drivers and PC hardware this time.

One unanticipated development based on StealthMac technology was the Mac mini. Jobs used this as one way Apple could see some return on investment from the project, as it had already designed a Mac motherboard that was sufficiently small.

A Dead End?

A later approach took Apple's notebook technology and did everything it could to put a complete Macintosh (sans optical drive) in an external enclosure that looked like a run-of-the-mill 3.5" external USB hard drive. The theory was that a Mac user could take the StealthMac to and from work, connect it to a USB or FireWire port, automatically run drivers from a small DOS partition, and Mac away.

The problem was USB itself. The external StealthMac would be accessed using VNC (Virtual Network Computing), but Apple wasn't ready to embrace USB 2.0, and FireWire never made big inroads on Windows. VNC worked over USB 1.1, which was a standard feature of all PCs at the time, but at high resolutions and high bit-depth, it bogged down the whole USB subsystem.

The biggest advantage of the external StealthMac is that it could have been used with any Windows PC that has USB, and it would have been far more viable if Apple had been willing to embrace USB 2.0 earlier. In fact, thanks to VNC, the external StealthMac could have been used with any computer with a VNC client - Unix, Linux, Mac, etc.

StealthMac X

PCI is on its last legs, while PCI-X and PCIe are not as well established, limiting the market for a Mac on an expansion card using one of the newer standards. Besides which, more and more Windows PCs are coming with less and less expansion slots to keep prices down in the very competitive low-end PC market.

The same goes for optical drive bays. Where expansion options are important for servers, high-end workstations, and power users, low-end PCs may not have an empty optical drive bay, reducing the market for that solution.

The external StealthMac solution has many proponents, as it would allow a user to bring his or her personal Mac to work, and advances in technology (1.8" hard drives, Solid State Drives, Atom and low power Core 2 CPUs - basically everything that makes the MacBook Air possible) mean it could be as small as a bus-powered 2.5" external hard drive. USB 2.0 provided both the power to run the StealthMac X and sufficient bandwidth for VNC.

StealthMac X can run in NetBoot mode, which goes one up on the MacBook Air's wireless NetBoot mode - it can connect to any mountable partition or mounted disk image on the remote Windows PC (or Mac) using USB or 802.11x WiFi, eliminating the need for its own hard drive or SSD. USB 2.0 is still something of a bottleneck, but it's usable. When USB 3.0 comes to market, StealthMac X should scream.

The drive-free version of StealthMac X could conceivably sell for under US$600, since it needs no power supply, hard drive, video port, etc. One USB port plus WiFi and Bluetooth provides all the connectivity and power it needs, although it does have a second USB port for a dedicated device that doesn't require bus power - that could be a powered hard drive, for instance.

This could also be a way for PowerPC Mac users with USB 2.0 ports to go Intel without investing in a whole new computer. Connect StealthMac X, run your VNC client software, and you've got full access to Intel Mac power on your existing Mac.

Apple has developed optimized VNC clients that can run in full screen mode for every version of Mac OS X since 10.2.8. (The Classic Mac OS supports VNC, but it doesn't support USB 2.0, so while you could conceivably use StealthMac with Mac OS 9, the limited bandwidth of USB 1.1 would be a significant drawback.)

StealthMac I

Apple has continued to develop a drive-bay solution, code named StealthMac I (for internal). Power draw and size are not as important as they are for StealthMac X, so it used a conventional Core 2 CPU and, like the Mac mini, has room for its own notebook hard drive.

Living inside a Windows PC, StealthMac I has full speed access to its drives, making a dedicated hard drive unnecessary. While it would ideally have its own dedicated drive or partition, StealthMac I can be run from a disk image - which doesn't even have to be mounted by Windows, in contrast to StealthMac X.

As with that project, StealthMac I has a NetBoot mode that can boot from any mounted partition or any Mac-formatted disk image on any mounted partition. It has two USB ports to handle I/O with the host computer using internal USB ports and draws its power from the host computer's power supply.

With dual USB ports, each with its own controller, one can be used to stream data from the host to StealthMac I while the other can be dedicated to the VNC connection, making this the fastest StealthMac solution to date.

Depending on the CPU selected, which may range from a 1.6 GHz Atom to who knows what on the top end (quad-core CPUs are likely someday), and because it has no drives of its own, pricing could easily enter netbook and cheap PC territory. Our sources tell us that a 2.0 GHz Core 2 Duo version with GeForce 9400M graphics and OS X 10.5 on DVD could sell for US$399 - or US$499 with iWork, iLife, and 90 days of MobileMe.

did I forget to mention that because StealthMac I also interfaces to the host computer using VNC, it's as much a solution for Linux and Power Mac users as it is for Windows users? All you need is USB 2.0 and an available optical drive bay.

Take that, Psystar! And longtime Mac users, put one in your Beige G3 and boot it!

(As always, we have no indication that either of these solutions will ever be released. We can dream, though!)

- Anne Onymus