They're still around under HPE, though they're not exactly advertised. It moved from a proprietary CPU->MIPS->Itanium->X86-64. When Compaq owned them I believe

They're still around under HPE, though they're not exactly advertised. It moved from a proprietary CPU->MIPS->Itanium->X86-64. When Compaq owned them I believe there was a brief port to Alpha. Interesting Systems. The primary/backup process-pairs especially. HP used to have an archive of the Tandem Technical Reports and Systems Review, but it seems to be gone. Bitsavers has some of the Tech Reports https://bitsavers.org/pdf/tandem/technical_reports/ https://bitsavers.org/pdf/tandem/technical_reports/ Archive.org has the Systems Review https://archive.org/search?query=subject%3A%22tandem-systems-review%22 https://archive.org/search?query=subject%3A%22tandem-systems...