All Discover is is a graphical front end to your repositories, so the real question is “is everything in my repositories safe?”.

There are no guarantees in life, but if you’re using only the default official Debian repos you’re just about as safe as you can get. If you add extra repos, whether deb based or flatpak, Discover will only be as safe as whatever you’ve hooked it up to.

If only the biggest problem was messages starting “I asked ChatGPT and this is what it said:”

A far bigger problem is people using AI to draft text and then posting it as their own. On social media like this, I can’t count the number of comments I’ve encountered midway through an otherwise normal discussion thread, and only clocked 2 paragraphs in that I’m reading a chat bot’s response. I feel like I’ve had time and braincells stolen from me in the deception for the moments spent reading and attempting to derive meaning from it.

And just this week I received an application from someone wanting work in my office which was very clearly AI generated. Obviously that person will not be offered any work. If you can’t be bothered to write your own “why I want to work here” cover letter, then I can’t be bothered to work with you.

Git is the underlying code management and version control system. It can be used directly, and also forms the backend to a number of other systems.

Code “forges” are platforms which integrate a version control system (like git), a code repository (a file server), and front end utilities.

Some git forges are open source, others are proprietary. Certainly with the open source ones, but also with the proprietary ones in some cases, you can either self-host or use a hosted service.

GitHub is a proprietary forge, and GitHub.com is the company’s fully hosted service. They’re now owned by Microsoft.

Gitlab is an open source forge. Gitlab.com offers a hosted service, but many projects self-host.

Forgejo is a fork of Gitea which is a fork of Gogs. These are all also open source. As far as I know, neither Forgejo nor Gogs offer a hosted version, but Gitea does.

A few other notable forges include GNU Savannah (open source), Bitbucket (proprietary), Sourceforge (proprietary), Launchpad (open source), Allura (open source).

At the end of the day, they all do the same thing. They have different feature lists (especially around some of the project management and user interaction side), different user interfaces (some are shinier and more modern, others more minimalist), and different communities and support models. You choose that one that works best for your needs.

GitHub is probably the most feature-rich (and/or bloated) of them. GitLab is competing in the same space, and self-hosted GitLab seems to be something of a sweet spot for many projects that want a premium experience without needing to use a proprietary Microsoft product. I don’t have much experience with Forgejo or Gitea. The rest tend to exist in their niches.

Not all mainframes are ancient; new models are still designed and sold to this day. And the brand spanking new mainframes may still be running COBOL code and other such antiquities, as many new mainframes are installed as upgrades for older mainframes and inherit a lot of legacy software that way.

And to answer your question: a mainframe is just a server. A specific design-type of server with a particular specialism for a particular set of usecases, but the basics of the underlying technology are no different from any other server. Old machines (mainframes or otherwise) will always consume far more power per instruction than a newer machine, so any old mainframes still chugging along out there are likely to be consuming a lot of power comparable to the work they’re doing.

The value of mainframes is that they tend to have enormous redundancy and very high performance characteristics, particularly in terms of data access and storage. They’re the machine of choice for things like financial transactions, where every transaction must be processed almost instantly, data loss is unacceptable, downtime nonexistent, and spikes in load are extremely unpredictable. For a usecase like that, the over-engineering of a mainframe is exactly what you need, and well worth the money over the alternative of a bodged together cluster of standard rack servers.

See also machines like the HP Nonstop line of fault-tolerant servers, which aren’t usually called mainframes but which share a kinship with them in terms of being enormously over-engineered and very expensive servers which serve a particular niche.