systm rchtctr s th cncptl mdl tht dfns th strctr, bhvr, nd vws f systm. n rchtctr dscrptn s frml dscrptn nd rprsnttn f systm, rgnzd n wy tht spprts rsnng bt th strctrs nd bhvrs f th systm.
systm rchtctr cn cnsst f systm cmpnnts nd th sb-systms dvlpd, tht wll wrk tgthr t mplmnt th vrll systm. Thr hv bn ffrts t frmlz lnggs t dscrb systm rchtctr, cllctvly ths r clld rchtctr dscrptn lnggs (DLs).