> bzip might be suboptimal as a general-purpose compression format, but it’s great for text and code. One might even say the b in bzip stands for “best”.
I've just checked again with a 1GB SQL file. `bzip2 -9` shrinks it to 83MB. `zstd -19 --long` to 52MB.
Others have compressed the Linux kernel and found that bzip2's is about 15% larger than zstd's.
It wouldn't surprise me at all that "more modern" compression techniques work better on larger files. It also wouldn't surprise me too much if there was no such thing as a 1GB file when bzip was originally written, according to Wikipedia bzip2 is almost 30 years old "Initial releases 18 July 1996". And there are mentions of the preceding bzip (without the 2) which must have been even earlier than that. In the mid/late 90s I was flying round the world trips with a dozen or so 380 or 500MB hard drives in my luggage to screw into our colo boxen in Singapore London and San Francisco (because out office only has 56k adsl internet).
For instance, "lrzip -b", which uses bzip2 for compression, typically achieves much higher compression ratios on big files than using either xz or zstd alone. Of course, you can also use lrzip with xz or zstd, with various parameters, but among the many existing possibilities you must find an optimum compromise between compression ratio and compression/decompression times.
I compressed kernel 6.19.8 with zstd -19 --long and bzip3 (default settings). The latter compressed better and was about 8x faster.
It was long surpassed by lzma and zstd.
But back in roughly the 00s, it was the best standard for compression, because the competition was DEFLATE/gzip.
You can bzip2 -9 files in some source code directory and tar these .bz2 files. This would be more or less equivalent to creating ZIP archive with BWT compression method. Then you can compare result with tar-ing the same source directory and bzip2 -9 the resulting .tar.
Then you can compare.
The continuous mode in RAR was something back then, exactly because RAR had long LZ77 window and compressed files as continuous stream.
'Solid compression' (as WinRAR calls it) is still optional with RAR. I recall the default is 'off'. At the time, that mode was still pretty good compared to bzip2.