the system/370 or s/370 was a mainframe architecture, ibm built in the 1970s. the system was mostly compatible with system/360, which ibm had built before. &gt;many applications coulds be re-used. the biggest change was that s/370 could handle virtual memory. the s/370 used tape drives and hard drives as mass storage device. the system/390 replaced the system/370 in the 1990s.