About +8% compared to lzma. Decompression time though:
<span style="color:#323232;">zstd -d -k -T0 *.zst 0,68s user 0,46s system 162% cpu 0,700 total
</span><span style="color:#323232;">lzma -d -k -T0 *.lzma 4,75s user 0,51s system 99% cpu 5,274 total
</span>
They both have their use cases. Zstandard is for compression of a stream of data (or a single file), while 7-Zip is actually two parts: A directory structure (like tar) plus a compression algorithm (like LZMA which it uses by default) in a single app.
Well when using zstd, you tar first, something like tar -I zstd -cf my_tar.tar.zst my_files/*. You almost never call zstd directly and always use some kind of wrapper.
Sure, you can tar first. That has various issues though, for example if you just want to extract one file in the middle of the archive, it still needs to decompress everything up to that point. Something like 7-Zip is more sophisticated in terms of how it indexes files in the archive, so I’m looking forward to them adding zstd support.
FWIW most of my uses of zstd don’t involve tar, but it’s in things like Borgbackup, database systems, etc.
WEBP images. The worst image file format on earth to deal with metadata and timestamps. FFFFUUUUUCK WEBPOOP (and no AVIF please).
XNViewMP is a saviour on all OSes though, thankfully, being the only tool that can batch convert webpoops to any proper image format with preserved metadata.
Atleast with renamed ZIP files, I literally do not need to care as long as 7-Zip or PeaZip is installed, so I can just “open as * archive”. And for video/audio, have MediaInfo installed on any OS. You will thank me someday.
WEBP is very weird to convert to other formats and retain metadata. This is not a problem with JPG, PNG and other formats. And only one tool I mentioned solves that problem.
Google is responsible for this problem. They created WEBP, which was not necessary to adopt, but shoved it in our throats via Chrome saving images as WEBP by default, and making websites that use their cloud as CDN serve WEBPs in general.
Nothing wrong with that… Most people don’t need to reinvent the wheel, and choosing a filename extension meaningful to the particular use case is better then leaving it as .zip or .db or whatever.
Totally depends on what the use case is. The biggest problem is that you basically always have to compress and uncompress the file when transferring it. It makes for a good storage format, but a bad format for passing around in ways that need to be constantly read and written.
Plus often we’re talking plain text files being zipped and those plain text formats need to be parsed as well. I’ve written code for systems where we had to do annoying migrations because the serialized format is just so inefficient that it adds up eventually.
SQLite explicitly encourages using it as an on-disk binary format. The format is well-documented and well-supported, backwards compatible (there’s been no major version changes since 2004), and the developers have promised to support it at least until the year 2050. It has quick seek times if your data is properly indexed, the SQLite library is distributed as a single C file that you can embed directly into your app, and it’s probably the most tested library in the world, with something like 500x more test code than library code.
Unless you’re a developer that really understands the intricacies of designing a binary data storage format, it’s usually far better to just use SQLite.
Back in the day, when bandwidth was precious and porn sites would parcel a video into 10 second extracts, one per page, you could zip a bunch of these mpeg files together into an uncompressed zip, then rename it .mpeg and read it in VLC as a single video. Amazing stuff.
TAR stands for Tape ARchive. It’s called that because it’s designed to be written to (and read from) non-seekable magnetic tape, meaning it’s written linearly. The metadata for each file (name, mtime etc.) immediately precedes its contents. There is no global table of contents like you’d find on an actual filesystem. In fact, most implementations of tar don’t even put the separate files on gzip boundaries meaning you can’t decompress any given file without decompressing all of the files before it. With a tape backup system, you don’t care, but with a filesystem you absolutely do.
PKZIP mimics the traditional filesystem structure much more closely. The table of contents is at the end instead of the beginning, which is a bit strange as filesystems go, but it is a table of contents consisting of a list of filenames and offsets into the file where they can be found. Each file in a zip archive is compressed separately, meaning you can pull out any given file from a ZIP archive without any prior state, and you can even use different compression algorithms on a per-file basis (few programs make use of this). For obvious reasons, the ZIP format prioritizes storage space over modification speed (the table of contents is a single centralized list and files must be contiguous), meaning if you tried to use it as a filesystem it would utterly suck – but you can very readily find software that will let you read, edit, and delete files in-place as though it were a folder without rewriting the entire archive. That’s not really possible with a .tar file.
You could make the argument that tar is able to more closely mimic a POSIX filesystem since it captures the UNIX permission bits and ZIP doesn’t (ustar was designed for UNIX and pkzip was designed for DOS) but that’s not a great metric.
xls & co. (the older ones) are something custom. Only after standardization as OOXML (a shitshow btw, there’s a lengthy wiki article about it) they got zip.
The whole Word and Libre/OO-Writer world is a shit show.
So complex and everyone decides to interpret it a bit differently.
Not even Libre and OO can be interoperabel between the same file and feature.
Ah, last time I checked it was a kind of ML directly (XML, I’m guessing from [email protected] their comment), but that’s back in Office 2016’s time, so things might have changed.
See, ZIP files are strange because unlike most other archive formats, they put the “header” and table of contents at the end, and all of the members (files within the zip file) are listed in that table of contents as offsets relative to the start of the file. There’s nothing that says that the first member has to begin at the start of the file, or that they have to be contiguous. This means you can concatenate an arbitrary amount of data at the beginning of a ZIP file (such as an exe that opens its argv[0] as a zip file and extracts it) and it will still be valid. (Fun fact! You can also concatenate up to 64KiB at the end and it will still be valid, after you do some finagling. This means that when a program opens a ZIP file it has to search through the last 64KiB to find the “header” with the table of contents. This is why writing a ZIP parser is really annoying.)
As long as whatever’s parsing the .exe doesn’t look past the end of its data, and whatever’s parsing the .zip doesn’t look past the beginning of its data, both can go about their business blissfully unaware of the other’s existence. Of course, there’s no real reason to concatenate an executable with a zip file that wouldn’t access the zip file, but you get the idea.
A common way to package software is to make a self-extracting zip archive in this manner. This is absolutely NOT to say that all .exe files are self extracting .zip archives.
So does Scrap Mechanic (sandbox game that’s basically Space Engineers on the ground – or, more loosely, Minecraft but with physics and you can build cars) also uses sqlite to save worlds. It also uses uncompressed JSON files to store user creations.
a lot of the time i handle it manually since i try to pack things in “volumes” that most closely mimic physical releases, and writing the code to get that information would be slower than just looking it up manually
so, for example, the first volume of bleach has 7 chapters, so i’d pack those 7 chapters together into one cbz, the second volume in another cbz, etc.
doesn’t sqlite explicitly encourage this? I recall claims about storing blobs in a sqlite db having better performance than trying to do your own file operations
Thanks for the hint. I had to look that up. (The linked page is worth a read and has lots of details and caveats.)
The scope is narrow, and well documented. Be very wary of over generalizing.
The measurements in this article were made during the week of 2017-06-05 using a version of SQLite in between 3.19.2 and 3.20.0. You may expect future versions of SQLite to perform even better.
SQLite reads and writes small blobs (for example, thumbnail images) 35% faster¹ than the same blobs can be read from or written to individual files on disk using fread() or fwrite().
Furthermore, a single SQLite database holding 10-kilobyte blobs uses about 20% less disk space than storing the blobs in individual files.)
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