According to Wikipedia [1], the FAA's Host system was upgraded in 1999 to IBM 9672 computers, so the computers aren't that old. It seems inaccurate to call this

According to Wikipedia [1], the FAA's Host system was upgraded in 1999 to IBM 9672 computers, so the computers aren't that old. It seems inaccurate to call this a 40 year old system when the computers are less than 20 years old. As for the original IBM 9020 computers running Host, these were IBM 360 variants. The technology in these computers is interesting - instead of newfangled ICs, the computers were built from SLT modules. These are metal modules kind of like an integrated circuit, except there's a small circuit board inside with discrete transistors, diodes, and printed resistors. (I was looking at some SLT modules yesterday.) [1] http://en.wikipedia.org/wiki/IBM_9020 http://en.wikipedia.org/wiki/IBM_9020