Chunk -- Simple, fast file splitter

Chunk was written to serve one purpose, and do it well: Split files into differently-sized chunks, primarily so that large files can be transported via media that is smaller than the size of the file. In fact, the specific application for developing this particular program is copying large files onto floppy disks for transport on/off an old computer, but of course you can use it for any purpose that requires splitting a file into chunks (or combining chunks into a file).

You can download Chunk v0.1 here

Features:

• Fast! (uses up to 128K RAM to buffer I/O)
• Robust floppy disk support. Diskette Mode automatically prompts for new disks without requiring the user to press any keys; Automatic mode automatically determines the amount of free space to use on the target.
• Simple and flexible command-line usage (switches can be - or / and appear anywhere on the command line)
• Non-proprietary; each chunk is numbered sequentially, and no additional junk is added to each file.
• Lots of error checking and verbose error messages.
• Follows the oldskool.org credo: Works On Any Machine(tm) In fact, it was coded on an original IBM Model 5150 (4.77MHz 8088).

The basic principle behind splitting files with chunk is to supply an input filename with extension, and Chunk produces a set of output files with a base name and increasing sequential extensions. This means, if you tell it to split with a basename of "output", it creates files called "output.000", "output.001", "output.002", etc. Unlike some splitting utilities, no additional information is written to each chunk, nor is any index file created or maintained. This is intentional, as I hate that crap (it locks you into using just that utility).

Re-combining chunks into the original file requires access to the sequentially numbered chunked files. Chunk looks for them in sequential order, and then adds them to the target filename.ext until it can't find any more. (In Diskette mode, there is no way for Chunk to know which file is the last one unless one of two conditions occur: a chunk is found that is smaller than the previous chunks, or the user presses a key to signify the last diskette has been read.)

Usage:

Chunk <options> [source] [target] <options>
where
  [source] and [target] are either a full filename.ext or a basename (a
  filename without an extension) depending on usage (see below).
  <options> can appear anywhere on the command-line, and can be delimited
  by either "/" or "-".

Splitting options are:
  /s<num> Size of each chunk in bytes.  If size ends in K or M, size will
          be in kilobytes (1024 bytes) or megabytes (1048576 bytes).
          Example:  "chunk filename.ext basename /s256k"

  /f<num> Size of chunks appropriate for a blank/formatted floppy of size 
          Available sizes are 160, 180, 320, 360, 720, 1200, and 1440.
          Example:  "chunk filename.ext basename /f360"

  /n<num> Number of chunks to make.  File will be split into N chunks.
          Example:  "chunk filename.ext basename /n5"

  /a      Autosize mode enabled.  Size of each chunk will be determined
          by the amount of free space on the target.  Diskette mode required.
          Example:  "chunk /d /a filename.ext a:basename"

Combining options are:
  /c      Combine split parts into file.  Chunk extension must be zero-padded.
          Example: "chunk /c basename filename.ext"

Diskette options are:
  /d      Diskette mode enabled.  User will be prompted to switch disks.
          Example (splitting): "chunk /d /f360 filename.ext a:basename"
          Example (combining): "chunk /c /d a:basename filename.ext"

  /e      Erase contents of diskette before writing target.
          There is no user prompting with this command -- use with caution!
          Example:  "chunk /d /a /e filename.ext a:basename"

General options are:
  /h[w]   Print command-line usage.  If called as /hw, help text will
          be written to the file "chunk.txt"

  /v[c]   Verify readability of target file(s).  This re-reads the target
          to ensure it is readable.  If called as /vc, data buffers are
          compared byte-for-byte to ensure file was written correctly.
          Example: "chunk filename.ext basename /n5 /v"

  /o      Overwrite.  If set, target(s) will be overwritten without prompting.
          Example: "chunk filename.ext basename /n5 /o"

Examples:

You get the idea.

To-Do List:

• /v[c] isn't implemented yet. Sorry, but I want to get this thing out the door so I can put this 8088 away and resume production on Mindcandy Vol. 2. If you simply MUST have verification, do this:
1. "set VERIFY=ON" at DOS prompt or in autoexec.bat
2. Make chunks with /f parameter ("chunk /f360 filename.ext basename")
3. Copy each chunk ("basename.000", "basename.001", etc.) manually.
• DOS errorlevel codes are not returned. If you want this implemented so you can use Chunk in batch files, let me know, as I would be flattered :-)

Known Bugs/Issues:

• Source files with the readonly flag set are not recognized due to lack of proper error handling by Turbo Pascal (ioresult returns 103, File Not Open, which makes no damn sense). If you are trying to split files directly off of a CDROM, you will probably get bitten by this. This can be fixed with additional error checking, but see above point about why /v[c] isn't implemented yet.
• I have only tested this utility on an 8088 running MS-DOS 6.22. If it doesn't work for you, let me know what you're running it on/under and I'll try to fix it.
• Because integers are used for the chunk extensions (*.000, *.001, etc.), you are limited to making no more than 1000 chunks. I'm sure this won't be a problem for most people, but thought I should mention it.

License and source code:

This program is free for use by any individual for any purpose, under the understanding that the author of this program is not liable for any damages incurred from the use or mis-use of this program. I wrote it and I use it myself, but that doesn't mean you have to, and I cannot be held responsible if something bad happens.

The source code is included in the source\ directory. You should be able to recompile and re-make the executable using everything there, although some editing of the build.bat file will be necessary for your system. Turbo Pascal 7.0 is required, although you should be able to use anything that properly implements the objects unit (specifically TStream and its descendants).

If you make any additions or corrections to the source code, let me know so that I can incorporate them into the official distributable file on www.oldskool.org/pc.

Greets:

Greets to the owb crew, and anyone who still uses computers more than two decades old.