The \fBcupsd\-helper\fR programs perform long-running operations on behalf of the scheduler,
.BRcupsd(8).
The \fBcups-deviced\fR helper program runs each CUPS
.BRbackend(7)
with no arguments in order to discover the available printers.
.LP
The \fBcups-driverd\fR helper program lists all available printer drivers, a subset of "matching" printer drivers, or a copy of a specific driver PPD file.
.LP
The \fBcups-exec\fR helper program runs backends, filters, and other programs. On macOS these programs are run in a secure sandbox.
.SHFILES
The \fBcups-driverd\fR program looks for PPD and driver information files in the following directories:
.nf
\fI/Library/Printers\fR
\fI/opt/share/ppd\fR
\fI/System/Library/Printers\fR
\fI/usr/local/share/ppd\fR
\fI/usr/share/cups/drv\fR
\fI/usr/share/cups/model\fR
\fI/usr/share/ppd\fR
.fi
.LP
PPD files can be compressed using the
.BRgzip(1)
program or placed in compressed
.BRtar(1)
archives to further reduce their size.
.LP
Driver information files must conform to the format defined in
.BRppdcfile(5).
.SHNOTES
CUPS printer drivers, backends, and PPD files are deprecated and will no longer be supported in a future feature release of CUPS.
Printers that do not support IPP can be supported using applications such as