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Binary files on Usenet

RAR and File Splitters

You already learned what a Multipart Message is, but Multipart Messages have a big disadvantage. Imagine you are posting a huge file (e.g. 200 MB) and you limit the size of each post to 600 KB (what will result in very good distribution). That means you will get 455 parts (size blowup of MIME or UUEncode has been considered. Now assume that one person can't decode the file, because part number 267 is missing ... what will you do?

The perfect solution would be to simply post part 267 again ... unfortunately most clients don't support reposting only one part. In case part 267 can be found on your own server, you can download this part, copy the content of it and paste it into a new post. That way you can circumvent the limitations of your client. But what if part 267 never showed up anywhere, neither on your own server, nor on any other server. Because of a server bug it was lost. What are you doing now? Reposting the all 455 parts? Good luck!

Not only that this wastes a lot of your time, it also wastes a lot of bandwidth and disc space on the server (which now has 532 MB, instead of 266 MB!!!). And people wonder why Usenet is getting into trouble because of binaries. Exactly to avoid such a disaster, people break large files into smaller pieces (e.g. every piece is 4 MB) and then post every piece seperately (whereby every piece is again split into smaller pieces of 600 KB by the Usenet client). In the worst case, you only have to repost a whole piece (4 MB) and not the whole file (266 MB). There are two techniques how to break files into pieces before posting and I will show you both.

RAR

RAR is a similar file archiver like ZIP, but it has three advantages compared to ZIP:

1. RAR files have a lot better compression.
2. RAR supports a special recovery system for broken archives.
3. RAR allows you to split the archive into smaller pieces.

The disadvantage of RAR is: Compression is very slow compared to ZIP.

When creating a new RAR file, you can choose the maximum size per archive, RAR will then create multiple files, with the extensions .RAR, .R01, .R02, .R03, etc. If you now want to decompress the content of such a split RAR file, you simply open the .RAR file (e.g. with WinRAR) and compress the files like usual. You don't have to reunite the parts before decompressing, RAR will jump from part to part during decompression on its own.

As you can see, RAR is an easy, but very effective way of splitting files into smaller pieces before posting. If you read the next sub-chapter ("How to post binary files correctly"), I will give you some tips on how to operate WinRAR, how to achieve best compression possible and how to make use of RARs great recover system.

File Splitters

File Splitters are applications that split files into smaller pieces. Unlike RAR, they usually don't apply any kind of compression to the file, they just split it. If you split a file named TEST.MPG, you will receive TEST.MPG.000, TEST.MPG.001, TEST.MPG.002, and so on. To reunite the file, you'll usually need a file splitter application (needn't be the one used for splitting), but you can also reunite the parts without a file splitter.

Some file splitters create a .BAT file, that users only have to place into the same directory as the parts and then run it. It will reunite all files automatically. Sometimes such a .BAT file is included with a post, sometimes it isn't. In case you don't see any .BAT file, it's no real problem as you can create such a .BAT file yourself.

Place all files into one directory and create a new .BAT file there (e.g. create RUNME.BAT). Now open this BAT file in an editor (e.g. Notepad). For this example I assume the files are named TEST.MPG.xxx (xxx = a number). The BAT file would look the following way:

Continue according to this scheme for all parts.
Important: Please notice that the first line differs from all the other lines. Further please notice that the file names are always in quotation marks, which aren't always necessary, but in general it's better to always use them (in case of file names that contain spaces, it IS necessary). Once you run the file, it might take some time so please be patient.

There are two easier ways, which don't always work. If you have to reunite only very little files, you can try to reunite them within a single line:

But if the line gets too long, it won't work. What the maximum line length is depends on your system and how it is configured. If you saved the files in the correct order (first .000, second.001, third .002, etc.), you may also try the following:

But it only works if you really stored the files in the correct order, as the parts will be reunited in the order you saved them to disc and if that order is wrong, they will be reunited incorrectly. That has something to do with the way how Windows saves files (and once again shows us, why Windows is not a real Operating System, but just some crappy application that pretends to be an Operating System). You should try this last solution anyhow, because if it works, you saved yourself a lot of work and if it doesn't, you can simply delete TEST.MPG and try one of the other two possibilities.

Linux user simply type

and it will always work, regardless in which order you saved the files.

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