I was installing MacTeX on my MacBook Pro today and had an amusing realization. First, some background: for those of you who don't know, TeX is a phenomenal family of typesetting programs originally written in 1978 by two of the giants of 20th Century computer science, Don Knuth and Guy Steele. Most people now use it in conjunction with a slightly more modern set of extensions called LaTeX released in 1981 or so. I used TeX/LaTeX to typeset several thousand pages of homework and other assignments in college.

Now, in early 2014, the download for the OS X distribution of TeX+LaTeX is 2.3GiB, and it actually occupies about 3.5GiB of disk space when installed. How does this compare to 1978? Well, one of the cheapest options for storage in 1978 was the DEC RK05, a gargantuan 2.5MiB cartridge disk drive, which cost $7,900 for the drive and $99 for each disk.

To store the installation of MacTeX-2013, we'd need 1,434 of these disks. This would cost $149,866 ($543,133 in 2014 dollars) and would form a cylinder 14" in diameter and 358' tall¹, which would weigh about 100,000 pounds². Based on some cursory googling, this seems like it'd be a stack of disk cartridges roughly as tall as a 25-story skyscraper and weighing about as much as 10 African bull elephants. Also, apparently the cartridges have embedded read/write head magnets and will erase one another if left in close proximity³, so that stack would be a terrible way to store your data.

I wonder what Knuth and Steele think of the fact that their little typesetting software would be the largest building in a good fraction of the cities in the world?

At least it's still cheaper than San Francisco real estate.