IRAF$DEV - The DEV Directory (Aug 1986)
Fri Mar 21 20:36:00 MST 1997

This directory contains device descriptor tables and host system interface
information for the various devices accessed by IRAF.  With the exception of
the cache[gt].dat files, all these files are read at runtime hence new
devices can be interfaced without a sysgen in most cases.

    cacheg.dat, cachet.dat
	SPP include files, referenced in TTY, used to cache graphcap and
	termcap device entries for fast access.  [These are rarely touched
	any more although they are still functional - Mar97]

    devices
	Maps the logical (IRAF) device names of any allocatable devices to
	host system names.  Primary use is for magtape devices.  [Not used
	any more except in VMS/IRAF]

    edt.ed, emacs.ed, vi.ed
	Read by EDIT, EPARAM, and EHISTORY to determine the editor language
	and the host command to be used to call the host editor.

    graphcap
	Device information for all graphics terminals, plotters, and image
	displays.  If an entry is also in the cache file `cacheg.dat', the
	cache must be rebuilt before changes will take effect.

    help.db
	The compiled HELP database.  Tells HELP what packages and modules help
	is available for, and the names of the associaated help files.

    hostlogin, hosts, uhosts
	Network interface files.  Describe the nodes on the local network
	and how to talk to them.

    null
	The dev$null file.  I am not sure an actual file entry is still
	required for this special file, but it was in the beginning.

    pix.hhh, pix.imh, pix.pix
	The standard test image, dev$pix.imh, and the STF template header
	file, dev$pix.hhh, required to propagate the special VMS file type
	required by the STF format to new image header files.

    tapecap
    tapecap.<node>
	Magtape device capabilities file.  See os$zfiomt.c for a summary
	of device capabilities.  os$tape.c can be used as a standalone
	Unix task to exercise a tape drive to determine its capabilities.
	Tapecap files can be named either "tapecap.<node>" where <node> is
	the hostname of the server the tapecap file describes, or simply
	"tapecap" to provide a fallback for all servers.  The <node> form
	allows a single IRAF installation to be shared by multiple servers
	while still having distinct tapecap files for each.  The tapecap file
	for a server is located in the IRAF dev$ directory *on the server*.

    termcap
	Device information for all terminals and printers.  The printer
	info should be moved out into a PRINTCAP file at some point.
	If an entry is also in the cache file `cachet.dat', the cache must
	be rebuilt before changes will take effect.

    vdmfile.gki, vdmplot.gki
	Standard test GKI metacode files.  VDMFILE contains several test
	frames, VDMPLOT contains a single, more complicated plot, used to
	test and compare the resolution of different graphics devices.
