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A question for the more knowledgeable: I remember reading that OpenVMS was not ported to i386 (and later) because the CPU didn't have sufficient support. Can so
by zvrba 12y ago
A question for the more knowledgeable: I remember reading that OpenVMS was not ported to i386 (and later) because the CPU didn't have sufficient support. Can somebody elaborate on what exactly CPU features OpenVMS needs?
- ch_123 12y agoIt is sometimes claimed that x86 cannot support VMS because VMS makes use of four CPU protection rings, despite the fact that x86 has four protection rings...
- dfox 12y ago4 protection rings of x86 are mostly not usable for anything, as they apply to descriptors, not memory page (there is only single user/supervisor bit in page table entry). The whole 286 descriptor based memory protection model is mostly unusable for C-and-separate-processes multitasking model (and has relatively significant overhead).
- rollthehard6 12y agoIf you've not listened to it, this podcast is probably going to be of interest to you - http://www.imore.com/debug-29-jeff-mcleman-porting-kernels http://www.imore.com/debug-29-jeff-mcleman-porting-kernels (An interview with Jeff McLeman who worked at DEC, he discusses VMS/Alpha/NT kernel work)
- rwallace 12y agoThat was an excuse. The real reason was that management of the succession of companies that owned VMS saw it as a cash cow to be milked at the high profit margins associated with proprietary minicomputer systems, not as a mass-market product.
- elektronjunge 12y agoThey are porting it now: http://www.marketwatch.com/story/vms-software-inc-named-exclusive-developer-of-future-versions-of-openvms-operating-system-2014-07-31 http://www.marketwatch.com/story/vms-software-inc-named-excl...