Booting up the 3ESS

After several years of work, volunteers Astrid and Colin have gotten the 3ESS to the point where it is semi-reliably bootable. This was no easy task. This system was designed to start up once, and then run for tens of years.

The 3ESS is a telephone switch designed by Bell Labs in the mid-1970s. It consists of a pair of custom designed computers that control an analog switching fabric in real-time via several thousand scan and distribute points (think GPIO on modern hardware).

Chapter List:
00:00 Fuses & Converters
01:55 Tape Drives, Teletype, System Status Panel
02:41 Processors (CU 0, CU 1)
06:02 CU 0 Bootup Complete
06:40 Post-Boot Cleanup, Error Recovery
11:25 Running Diagnostics on CU 1, Re-tensioning Tape
15:15 Swap (Failover) from CU 0 to CU 1