Windows Cairo: Exploring a Myth Among Microsoft Operating Systems

On April 4th, Microsoft will celebrate an impressive 45 years of activity, a period in which we've seen and heard almost everything. Resounding successes, spectacular failures, half-finished experiments, and concepts that never saw the light of day are all part of its history. One of the most compelling for users is Cairo. For much of the general public, Cairo is the codename assigned to several internal builds of Windows NT, but in reality Cairo was... something else. A product, a combination of technologies, a wildcard, a promise.

The Genesis of Cairo

The story begins at the old "Microsoft Professional Developers" conference (now known as BUILD) in 1991. There, the brilliant and highly controversial Jim Allchin presented the basic idea of what would become Cairo, but enthusiasts had to wait two years (until the 1993 PDC) to be exposed to the first public beta. So... what exactly was Cairo?

What Was Cairo, Really?

The most solid reference we have about the true identity of Cairo goes back to a confidential draft created by Microsoft in March 1993. There, Greg Lobdell, a historical figure within the company, explains that Windows Cairo is "the second generation of Windows NT", and the first system to fulfill the vision of "Information at your fingertips" that Bill Gates originally spoke about in 1990. Cairo's original mission was to "deliver an advanced Windows operating system" to "share information" in a "distributed environment".

Here the text seems to confirm that Cairo would be an operating system. It would simply follow Windows NT regardless of its destination, and both would hold a privileged place on all corporate desktops, suggesting that the project did not prioritize the end user.

The ability to share information would be a fundamental piece of Cairo, with an adaptable design. Whether a company had two nodes or 200,000, it didn't matter: Cairo had to work across massive networks without a hitch. Another major idea behind Cairo (one suggested by Allchin) was that users could locate data by its content, not by the filename. In relaxed terms, seeing data more as objects.

From Promise to Vaporware

However, the years passed, and everything related to Cairo transformed from expectation to frustration, and then to mockery. An article published by BYTE in November 1996 called Cairo "the astute way of Microsoft to promise the world". Between July 1993 and August 1996, the Redmond giant released NT 3.1, NT 3.5, NT 3.51, and NT 4.0. None of them represented the original vision of Cairo... although the name ended up associated simply as a codename for NT 4.0. This is where we see the first "change of course" by Microsoft: Cairo would not be an operating system, but rather a collection of technologies. All the promises would be fulfilled with Windows NT 5.0...

... but Windows NT 5.0 became Windows 2000 (the definitive union of "corporate" and "residential" or, as they preferred in Redmond, "NT everywhere"), and Cairo became more vaporware than ever. Some might say its interface (and that of the entire Windows 9x family, with its icons and context menus) is deeply based on the initial work done on Cairo, and that content indexing today is part of the search system in the Windows desktop, but those are the most visible examples. Allchin himself called it "too ambitious" in an excellent interview with Wired at the end of '99.

In summary, Cairo never reached the market as the public expected, and Microsoft, whether due to technical limitations, short-term convenience, or internal conflicts, had to modify its identity more than once. An operating system that never materialized... and that from a certain point of view, has been with us for decades.