See this link for an idea:

http://www-132.ibm.com/content/home/store_IBMPublicUSA/en_US/eServer/iSeries/

The IBM iSeries mid-range computing platform is a highly available system running the proprietary OS/400. The processor is a 64-bit PowerPC RISC processor. This system has been doing 64 bit since the mid-'90s (it was 48-bit prior to that, since the '70s). All the hardware on this thing is proprietary but industrial strength. Disks are of the DASD variety.
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Isn't this the latest version of the architecture originally introduced by IBM (InternationalBusinessMachines) General Products Division in Rochester (MN, USA) as the System/38?

Yes, system/36 & 38 were the predecessors to the iSeries(AS/400).

''Ahh, yes -- the wonderful System/36-8. A totally locked up OS running on a uniquely pigeonholed architecture. No support in the third party market of any real depth, and even the IBM business partners avoided the things. Want to get shoved into a dark corner with no future? Then buy one of these beaters.''
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See: IseriesArchitecture

CategoryHardware, CategoryComputerCompany, CategoryComputerArchitecture