From the MS docs on installation formats here and here, the format used for the SourceDisksFiles section in TXTSETUP.SIF makes no sense to me. Some of those MS docs imply that I could CAB any number of these together and just reference a different source in the SIF, but the docs also say the format of SourceDisksFiles should be filename = diskid, subdir, size I have a line that looks like this accessS.chm = 1,,,,,,,21,0,0,access.chm which means, AFAIK: copy accessS.chm from disk 1 (1 = %cdname%,%cdtagfilei%,,\i386) to C:\WINNT\Help (21 = Help) and rename it to access.chm But what the heck are all of those ,,,,,'s in between, and also what are the 0,0,s? Some lines have values for those in the middle, implying that there are alternate sources or destinations or something for these files, but I don't see anything that shows what they really mean. Anyone have a good pointer (probably somewhere in these forums) as to what the other fields are? I'll update this section below as I figure out and/or get any reference values, assuming it may be of use to others in the forum: srcname = srcdisk, unk2, unk3, unk4, unk5, unk6, unk7, destinationdir, unk9, unk10, destinationfile