Some people have very large datasets; this can be problematic. BrainMaker reads its data from your hard disk, so as long as your file fits on your hard disk you won't have any problems. However, preparing large training files can be difficult. For example, if you have 400 columns of data and you want to load it into Excel, you'll have to split your data into two separate spreadsheets. NetMaker does not have this silly 256 column limit, but to use NetMaker first you have to get your data into a single flat file.
If your data is already broken up into several smaller files, here's one way to put them back together. First, download a copy of the shareware editor TextPad ($27 to register). From Excel, use File / Save As..., and choose Save As Type: Text (Tab Delimited) (*.TXT). If you're using a different program other than Excel, choose File / Save As... and use ascii, non-document mode, text only, space delimited, comma delimited, fixed length, or tab delimited. Your program will almost certainly support at least one of these.
In TextPad, open your first file. Now, select Configure / Block Select Mode. Open your second file, and move the cursor to the upper left hand corner of the document. Select a small amount of the file. Now, using the scroll bars, move the window so that the lower right hand corner of the document is visible. Move the mouse pointer to just past the lower right corner, hold the shift key down, and click the left hand mouse button. This will select a rectangle of text which includes your entire file. Now, select Edit / Copy, or hit Ctrl-C. Move back to your first document using Window, and move the mouse cursor past the right hand limit of the first line. Click the left mouse button. Now, select Edit / Paste or hit Ctrl-V
You have just joined your two files into one, and you may now save the results and read them into NetMaker.
At the time of this writing (April 25, 1998), TextPad is in release version 3.2.2, and has a silly limit of it's own: 4096 characters per line, max. I have been assured by the author this limit will be removed in a release in the near future.