> Databases reside on raw disks. There is no file system underneath the databases.
The terminology of "filesystem" here is confusing. The original database system was/is called Enscribe, and was/is similar to VMS Record Management Services - it had different types of structured files types, in addition to unstructured unix/dos/windows stream-of-byte "flat" files. Around 1987 Tandem added NonStop SQL files. They're accessed through a PATH: Volume.SubVolume.Filename, but depending on the file type, there is different things you can do with them.
> If you want a flat file, it has to be in the database.
You could create unstructured files as well.
> Processes can be moved from one machine to another
Critical system processes are process-pairs, where a Primary process does the work, but sends checkpoint messages to a Backup process on another processor. If the Primary process fails, the Backup process transparently takes over and becomes the Primary. Any messages to the process-pair are automatically re-routed.
> Unfortunately, it ended up at HP in the Itanium era, where it seems to have died off.
It did get ported to Xeon processors around 10 years ago, and is still around. Unlike OpenVMS, HPE still works on it, but as I don't think there is even a link to it on the HPE website* . It still runs on (standard?) HPE x86 servers connected to HPE servers running Linux to provide storage/networking/etc. Apparently it also runs supported under VMWare of some kind.
> Critical system processes are process-pairs, where a Primary process does the work, but sends checkpoint messages to a Backup process on another processor. If the Primary process fails, the Backup process transparently takes over and becomes the Primary. Any messages to the process-pair are automatically re-routed.
Right. Process migration was possible, but you're right in that it didn't work like Xen.
> It still runs on (standard?) HPE x86 servers connected to HPE servers running Linux to provide storage/networking/etc.
HP is apparently still selling some HPE gear. But it looks like all that stuff transitions to "mature support" at the end of 2025.[1] "Standard support for Integrity servers will end December 31, 2025. Beyond Standard support, HPE Services may provide HPE Mature
Hardware Onsite Support, Service dependent on HW spares availability." The end is near.
It looks like that Mature Support stuff is all for Integrity i.e. Itanium servers. As long as HPE still makes x86 servers for Linux/Windows, I assume NonStop can tag along.
Right, that's just the Itanium machines. I'm not current on HP buzzwords.
The HP NonStop systems, Xeon versions, are here.[1] The not-very-informative white paper is here.[2] Not much about how they do it. Especially since they talk about running "modern" software, like Java and Apache.
They were pretty much the only game in town, other than IBM and smaller mainframe vendors, if you wanted actual written, binding, guarantees of performance with penalty clauses. (e.g. with real consequences for system failure, such as being credited back X millions of dollars after Y failure)
At least from what I heard pre-HP acquisition, so it’s not ‘amazing lock in’, just that, if you didn’t want a mainframe and needed such guarantees, there was literally no other choice.
Well if just price/performance alone is enough to qualify… viz. IBM, Then the moment another mainframe vendor decided to undercut them by say 20%, the lock in would evaporate. Of course no mainframe vendor would likely do so, but the latent possibility is always there.
Facebook is an example of ‘amazing lock in’ where it’s not theoretically possible for any potential competitor to just negate it with the stroke of a pen.
In that sense IBM offers a better ‘game’ in every way, but at 10x the price point… because they are playing a different, more advanced, ‘game’ that so happens to include Tandem’s ‘game’ as a subset.
The terminology of "filesystem" here is confusing. The original database system was/is called Enscribe, and was/is similar to VMS Record Management Services - it had different types of structured files types, in addition to unstructured unix/dos/windows stream-of-byte "flat" files. Around 1987 Tandem added NonStop SQL files. They're accessed through a PATH: Volume.SubVolume.Filename, but depending on the file type, there is different things you can do with them.
> If you want a flat file, it has to be in the database.
You could create unstructured files as well.
> Processes can be moved from one machine to another
Critical system processes are process-pairs, where a Primary process does the work, but sends checkpoint messages to a Backup process on another processor. If the Primary process fails, the Backup process transparently takes over and becomes the Primary. Any messages to the process-pair are automatically re-routed.
> Unfortunately, it ended up at HP in the Itanium era, where it seems to have died off.
It did get ported to Xeon processors around 10 years ago, and is still around. Unlike OpenVMS, HPE still works on it, but as I don't think there is even a link to it on the HPE website* . It still runs on (standard?) HPE x86 servers connected to HPE servers running Linux to provide storage/networking/etc. Apparently it also runs supported under VMWare of some kind.
* Something something Greenlake?