In its initial concept, OpenVMS (then VAX/VMS) sought to provide the functionality and capabilities of a mainframe-class system at a small fraction of the size and cost, while at the same time providing higher levels of reliability and integrity. These goals were achieved by what has become OpenVMS' hallmark, an
emphasis on integrity and architectural leverage. Note: This is an entry to our OS Contest.
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Member since:2006-07-18
VMS is still being actively developed. Version 8.2 has been out for a while, and Version 8.3 is coming out soon. Field test versions are already in customer's and hobbyist hands.
As for logical names, I feel that to attempt to embrace the entire capability at once is too much. Uses are many. As a simple example:
Disk drives on a system have a device name, whether it be C:, D:, DKA100: DKA200:, etc. However, usage of the device names is rather rigid. Using logical names for the disks is much better. DKA100: may be named DISK1, DKA200: may be named DISK2:, and so on. Your programs, data, and whatever may be on DKA100:, but referenced as on DISK1:. Ok, DKA100: is having problems, generating errors, going to die soon. By moving your programs, data, and whatever to possibly DKA300:, and re-defining the logical name DISK1: to have the value of DKA300, you can continue working without any other changes.
Another simple example:
You have an application that runs in background, and wakes up periodically to determine whether it needs to do any work. Lots of ways to do this, but with logical names, it's real easy and flexible. The application can use a library routine to evaluate the value of the logical name 'ReadyToGo'. If the value is 'True', or 'Yes', or whatever the application is looking for, then it can proceed, else not. There are multiple ways of setting the value of a logical name, manually or from within another program. A simple method for interprocess communication and/or control.
Now start to imagine the uses for being able to have a known 'token', the logical name, and the capability of assigning a value to the name and testing the value of the name.
When working on windoz the lack of logical names is one of my two biggest complaints.
Member since:2006-07-19
Sharp VMS system managers will set things up so that a logical name for each disk is set up early in the startup process; furthermore, they should establish an ironclad rule that disks may never be referenced by their physical names, only their logical ones.
It not only makes disaster recovery easier, it makes subsititution of one disk for another a simple matter of changing a logical name.
Member since:2005-08-21
You know, the way you can create aliases for disk drives reminds me of AmigaOS. Can you do that also on a directory basis? AmigaOS assigned several aliases by default, like LIBS: to SYS:Libs/ and SYS: to the boot drive root directory (often DF0: or DH0:).
And now for the childish comment: I found it funny that there are at least two common acronyms used in the OpenVMS world that are also real persons in computer science or a related field: AST and RMS. (Andrew S. Tanenbaum and Richard M. Stallman, resp.)
Member since:
2005-07-06
Aye. Very well written article, very clear. Cleared up the 'Open' part of OpenVMS for me, finally, although the logical name translation is still a bit of a mystery to me.
Just curious: does OpenVMS have a large userbase, and is it being actively developped still?