Splitting and merging files

Go to File->Special->Split or Merge files menu command.

Splitting

I think everything is self-explanatory, maybe except the "Bytes per file" option. Along with choosing one of the predefined options, you can specify the size for yourself, examples:

1024 - a file will have 1024 bytes (1 KB)
10 KB - a file will have 10 KB
600 MB - a file will have 600 MB.

As you can see, you must specify a number and a unit (like B, KB etc...) if no unit is given, Bytes are assumed.

Merging

ACB can merge files with a number as their extension, like acb.exe.001. The first file selected must have 001 number. Then ACB will proceed with the rest.

You can copy all the files (like e.g. acb.exe.001, acb.exe.002) to one folder and click the 001 file to start merging (or choose File->Special->Merge files menu command).

If those files (001, 002 etc..) are on removable drives (like floppy disk), then alternatively you don't have to copy them to one location. Just start with the first disc, and insert next discs on request. Note, that ACB can't actually know when to finish, so every time there is another disc to use - press OK, and when it's finished - press Cancel.