CD_Check.COM is a TSR which fools PCBoard into  reporting files found in
an .IDX file exist even if the CD-ROM is not online.  It works by taking
over the DOS 21h interrupt and watching for a  Find First Matching (4Eh)
function call. If the Drive letter of the filespec is '@' then it copies
the filespec to the DTA buffer  filename area and  zeros the  DTA buffer
area for Size, Date & Time.

It should be loaded during your AUTOEXEC.BAT  file and only takes up 256
bytes of memory or less. You then need to change the Drive letter in all
offline CD-ROM .IDX files using IDX-DRIV.EXE or IDX-RSET.EXE  which will
check each CD-ROM and drive listed in CDROM.DAT and set the drive letter
on each path listed in the .IDX  file to the drive  where the CD-ROM was
located or to '@' if the CD-ROM was not found online.   At this time the
only a single character  drive letter change is  supported by both these
programs so those of you using a CD-ROM server will have  to make manual
changes to the paths using IDX-EDIT.EXE or running MAKEIDX again.

Only the .IDX for the OnLine CD-ROMS should be listed in your DLPATH.LST
file and ALL the .IDX  files should be listed in the ALLFILES DLPATH.LST
so PCBoard will only check the OffLine .IDX files during upload checking
and not during downloads.  IDX-RSET will take care of this automatically
for you.   You could also make a  second copy of the .IDX  files and use
IDX-DRIV to set the copies to drive '@' and then list all the  copies in
the ALLFILES DLPATH.LST and list all the origionals in all of the normal
DLPATH.LST files so you don't have to make changes as you change CD-ROM.

IDX-DRIV also comes in handy when changing a CD-ROM to another drive, as
you don't need to run MAKEIDX again just to change the drive letter.