Open Vms

Formerly called Digital VAX/VMS, once the king of the MiniComputer? world. Designed by DaveCutler. Had many features that were ahead of its time as well as mission-critical stability. VMS is short for VirtualMemorySystem?.

• VMS
  • http://www.openvms.org/
• Compaq HP
  • http://www.openvms.compaq.com/
  • http://h71000.www7.hp.com/
• Foldoc
  • http://www.foldoc.org/foldoc/foldoc.cgi?query=vms&action=Search

---

VMS started nine years after the UnixOperatingSystem and is very different from it (it doesn't have the Unix file model, from what I've heard).

What is "the Unix file model"?

VMS doesn't treat files and devices as streams of bytes. (Well, it can, but it's a little strange.) The VMS I/O system is based around blocks and fixed-size or variable-size records. In some ways, it is lower-level than Unix because you think in terms of block sizes and buffers and so on, but it also provides some high-level record-oriented features.

Porting Unix-style C programs to VMS can be difficult due to the differences. The VMS C runtime library tries to make VMS files work like Unix files do, but it's not a perfect emulation. (My experience with this is a few years old; maybe it is easier now.)

---

I had assumed OpenVMS was dead-and-buried, so I was very surprised to see a new book at the bookstore.

Getting Started With OpenVMS: A Guide for New Users by Michael D Duffy

ISBN 1555582796 .

According to the preface in the book, Compaq/HP have promised to continue supporting existing past 2010, and Alpha and Itanium beyond then.

Published in 2002. It seems misunderstood WikiNow.

---

The reason why it's still alive is because Indian Railways, one of the 10 biggest employers on the planet, uses it internally.

Actually, the reason it's still alive is its users think there's nothing better. Re their testimonials, I don't hear Windows and UNIX admins saying these things. -Nick P

http://h71000.www7.hp.com/openvms/35th/testimonials.html

---

CategoryOperatingSystem