[Epsilon Rose]

Originally Posted by Quoth

Yes, that's the only browsing. But it can search the Calibre Metadata file. A bit clunky, so I read novels on a Kobo using the Kobo metadata library to browse as it's perfectly supported by Calibre. Everything else is dramatically poorer and worst is file browsing.

Kobo:
Filter by read, reading or unread.
Sort by title, recent, collection, series, author etc.
Subtitle display

Search is faster than KOReader and lists hits of title, series, author, subtitle.
About 6,700 novels on my Kobo.

I'd like to point out that both Moon+ and Librera can filter by series, authors, tags, and several other things. Librera can also search by those things, though I'm less sure about whether or not Moon+ can search by all of those things and I don't know how either of them interact with Calibre's meta data specifically.

I can't imagine what you think the shortcomings of pocketbook app are.

I can't seem to find any way to filter your library by tags or what not. Search might work, but that's not always as convenient as filtering, especially when it seems to lack any form of auto complete. This might be due to the files I'm testing it with not coming from Calibre, but other reader apps seem to be able to pick up on their metadata just fine.

Actually, this touches on a major shortcoming that I've found with all of the apps I tried. Some of them let you filter your view based on various criteria (e.g. tag, author, series), but none of them seem to allow you to filter based on on multiple criteria, simultaneously, without resorting to a manually typed search. Similarly, they don't seem to have any ways to group how results are displayed after you do that filtering or sorting. For example, I might want to filter by Medium: Graphic Novels and Author: Neil Gaiman, and then view the results by series, rather than individual book. That way I could see all of the graphic novels series I have by Neil Gaiman and then I could select a specific series to see the individual issues I have. This seems like exactly the type of flexibility that tagging is supposed to allow vis-a-vis a folder structure based system, but it doesn't seem to actually be available anywhere. Am I missing something?

My tablet has a 256 G SD card and that has a copy of every document since about 1994, including 1000s of PDF scans of books, magazines and service information (mostly late 1800s to 1980s).

My old 2016 Laptop is 1T byte. My current laptop is 256 G SSD and 2T HDD. Workstation is 512G SSD and 4T 3.5" HDD.
Storage is cheap.
Several backup drives 1T to 6T.
Old server for backups is 1T + 2T drives.

I only used mainframes 1969 to 1973 and then personal micros from 1979.

I'm not entirely sure what this is supposed to prove? I'm glad your set up works well for you and lets you store a large number of documents, but I provided the real world numbers for my use case. They may be different than what you're working with, but that doesn't make them less valid. Similarly, just because I prioritize how I use my internal storage space differently does not mean my conclusions are invalid and I don't think "100GBs is too much space to dedicate to my library on my main PC" is a particularly strange conclusion. Storage may be cheap, but it's not free and laptops only have so many drive bays and usb ports available.

Originally Posted by Quoth

Calibre runs on Mac, Linux and Windows. Smallest HW an ARM based Raspberry Pi with Liinux.
It uses a local disk, only. At a pinch you can use a USB drive or SD card that's formatted with the native filesystem of the OS Calibre is using.

I do have an old pi just sitting in a box and I've been trying to figure out a project for it for a while, so I may try doing something with that, but that will add enough additional steps and complications to the project that I wouldn't want to start with it or even attempt it right now. This is the sort of thing I might do because I enjoy playing with electronics, not because it's a practical solution to my problem.

I find it strikingly strange that the idea of storing a library on an SD card, moving it between devices, and using an app to interface with it on Android is seen as such an impossible use case. Especially because, at the end of the day, all it really requires is an app that can interact with a library in the same way Calibre does or just reference the files Calibre already generates to do the same thing. The fact that Calibre already comes in a portable version means that someone already recognized that this is something users might want to do. It's just that the current implementation is limited to PCs, for some reason.