[Info-vax] Current VMS engineering quality, was: Re: What's VMS up to these

[Johnny Billquist]

On 2012-03-14 20.55, Michael Kraemer wrote:
> David Froble schrieb:
>>
>> Joining multiple computers into a cluster is not always a good idea.
>> Clusters have their uses. But non-cluster also has it's uses.
>>
>> As for a group of workstations, using one common system disk, and
>> ethernet for their cluster interconnect, well, I would call that a
>> "far from robust" configuration. As usual, you're only as strong as
>> your weakest link.
>
> Well, this was a very common configuration
> in the late 1980s/early 1990s. I'd say, VMS owes its former
> popularity to such clusters. And the people who run it
> claimed it was far superior to a collection of networked Unix boxen
> (which I wasn't even allowed to call "cluster").
> Unfortunately, as mentioned, the allegedly inferior Unix collection
> turned out to be more robust at the bottom line.

1. VMS clusters did not use ethernet originally.
2. Unix distributed networks using ethernet and shared disks is not 
robust at all. You must be totally uninformed if you claim this. Have 
you ever used a machine with an NFS root? Any time the server stopped, 
rebooted, or whatever, all clients *freeze*. Not even rebooting, unless 
you press the power switch. You just sit there waiting for the NFS 
server to wake up again.
3. Unix, using NFS, is weird and unreliable. File locking does not work 
properly. File renaming and deletion is troublesome, and deleting a file 
used over NFS is handled by actually not deleting the file, but instead 
renaming it to something starting with a period, so that you don't 
normally see it, creating the illusion that you deleted the file. 
Furthermore, security wise, it is a joke. You use mountd daemon to mount 
and access NFS disks, but if you know the file handles, you can totally 
skip the mounting, and thus also skip the permissions of the 
/etc/exports file.
4. Unix does normally not crash, but instead freeze. And not only if the 
network goes down, but also if the single machine serving the disk goes 
down. Also, if anything in the server configuration changes, all clients 
needs to be rebooted, no matter if the server comes back, since NFS 
don't allow any recovery in that case. And we are talking about very 
ungraceful rebooting here. No controlled take down. You'll have to reach 
for the reset or power switch, since controlled shutdown is impossible.

Oh, and by the way, these issues are not only relevant to machines 
having an NFS root. The same is true for any use of NFS. It's just that 
since the quoting reach back to "one common system disk", it boils down 
to the NFS root in Unix land.

You, as usual, have all kind of weird, uninformed claims and statements. 
You're more than a troll than anything else.

Go back to playing with Windows, and stop posting to this newsgroup, 
since you obviously have little to contribute anyway. And VMS and DEC 
bashing in general is not classified as "contributing".

>> For real-time work, you cannot wait for a cluster to recover from a
>> problem. Say you're capturing real time data. If you don't trust one
>> system, you'd be better off with two or more independent systems, with
>> independent power supplies, and the data feed split to go to every
>> system. Or for process control, and such.
>>
>> I've never used a cluster. Never needed the capability a cluster
>> provides. Very few of my customers ever needed a cluster. VMS is an
>> excellent OS even if you do not use the cluster capability.
>
> Hear hear.
> Aren't we told over and over again how clustering
> is *the* differentiating factor making VMS superior to
> everything else?

If cluster is what people need, then VMS does it better than Unix (by a 
long shot). Most people do not need clustering. What does that prove?

	Johnny