The control of instruments and telescopes is usually separated, although the two computers can communicate and for some applications the telescope is controlled from the instrumentation computer. The user interacts with the instrument-control software via the ADAM command language, which provides for data entry and checking, prompting, defaults and some procedural capability. A set of device-dependent tasks communicate, through CAMAC, with the individual instrument microprocessors. The configuration of each instrument in use is shown on a graphical Mimic display and spectra or images can be displayed on a Lexidata image display or a Printronix printer. Some data-assessment routines are available at the telescope. All data from electronic detectors are written to tape in FITS format.