The number of topic files affects the amount of time required to complete the build. Help files consisting of a small number of files compile quickly; Help files with large numbers of files can require several hours to compile. For large Help files, you might want to start the build process at the end of the day and let it compile at night. (You can also start a build at the MS-DOS prompt within Windows, and then change its settings to run in the background while you use other applications. For more information, see the Microsoft Windows User’s Guide.)
If your Help file is too large to build under MS-DOS, you can compile under OS/2 or use the DOS Protected Mode Interface (DPMI), or extended, version of the Help compiler (HCP.EXE). The extended version of the compiler uses the same syntax as HC.EXE, but it makes better use of memeory. All instructions for building under MS-DOS apply to these other versions unless otherwise indicated.