AS 400
(-The IBM System i (formerly known as iSeries, AS/400, and Application System/400) is a midrange computer platform produced by IBM. It was officially introduced as the AS/400 in 1988. It was then renamed to the eServer iSeries in 2000 as part of IBM's e-Server branding initiative. In 2006, the platform has once again been renamed to System i.-)
It's not obsolete, they are still being manufactured; this entry should be future-archived 
Since annual sales still total in the billions of dollars, the iSeries is as obsolete as the Ford Mustang!
Sounds like just the name is obsolete!
An analogy might help - AS/400(1988) - 57 Chevy Good car - for its time. I-Series(2008) - Millennium Falcon
Stable, expandable, backwards compatible, able to run multiple operating systems CONCURRENTLY, yeah that sounds real obsolete.
Actually, the AS/400 and its operating system (OS/400) ARE obsolete, but the successor machine (the System i) and operating system (i5/OS) are alive and well! In fact, from what I understand, IBM will soon assimilate the mainframe into the same hardware platform…