Software as Hardware: Apollo’s Rope Memory

Programs for the Apollo Guidance Computer were encoded by painstakingly threading wires through tiny magnetic cores

2 min read
Photo by Mark Richards/Computer History Museum
Photo: Mark Richards/Computer History Museum

Alan Kay, the pioneering computer scientist, has observed that “hardware is really just software crystallized early.” The rope memory device shown here, a prototype created in 1963 by Burroughs Corp. [PDF], makes Kay’s point. In rope memory, bits of information are represented by threads of wire and tiny doughnut-shaped magnetic cores. A core with wire threaded through the center represents a 1; an empty core represents a 0. In this way, the pattern of wires can form a computer program—software crystallized as hardware, in other words.

Keep Reading ↓ Show less

Stay ahead of the latest trends in technology. Become an IEEE member.

This article is for IEEE members only. Join the world’s largest professional organization devoted to engineering and applied sciences and get access to all of Spectrum’s articles, podcasts, and special reports. Learn more →

Membership includes:

  • Get unlimited access to IEEE Spectrum content
  • Follow your favorite topics to create a personalized feed of IEEE Spectrum content
  • Save Spectrum articles to read later
  • Network with other technology professionals
  • Establish a professional profile
  • Create a group to share and collaborate on projects
  • Discover IEEE events and activities
  • Join and participate in discussions

Tony Fadell: The Nest Thermostat Disrupted My Life

The Nest founder tells of years in pursuit of a thermostat he actually likes

7 min read
A man holds a circular device in front of a blue wall that says nest on it.

Tony Fadell shows off the Nest thermostat in 2012.

Karsten Lemm/picture-alliance/dpa/AP

The thermostat chased me for 10 years.

That is pretty extreme, by the way. If you’ve got an idea for a business or a new product, you usually don’t have to wait a decade to make sure it’s worth doing.

Keep Reading ↓ Show less
{"imageShortcodeIds":[]}