Fortran question for Unix System-5 r3. When executing fortran programs requiring "input" the screen will show a blank screen. After entering input anyway the program completes under Unix System V *r3*. When the same program is compiled under Unix System V *r1* it works as expected. The user sees the prompt. Sounds like on Unix System V *r3* the output buffer is not being flushed. I tried re-compiling F77. No help. Is it possible to check the runtime libraries to see if fflush is missing? Fortran program follows: PROGRAM EASTER INTEGER YEAR,METCYC,CENTRY,ERROR1,ERROR2,DAY INTEGER EPACT,LUNA C A PROGRAM TO CALCULATE THE DATE OF EASTER PRINT '(A)',' INPUT THE YEAR FOR WHICH EASTER' PRINT '(A)',' IS TO BE CALCULATED' PRINT '(A)',' ENTER THE WHOLE YEAR, E.G. 1978 ' READ '(A)',YEAR C CALCULATING THE YEAR IN THE 19 YEAR METONIC CYCLE-METCYC METCYC = MOD(YEAR,19)+1 IF(YEAR.LE.1582)THEN DAY = (5*YEAR)/4 EPACT = MOD(11*METCYC-4,30)+1 ELSE C CALCULATING THE CENTURY-CENTRY CENTRY = (YEAR/100)+1 C ACCOUNTING FOR ARITHMETIC INACCURACIES C IGNORES LEAP YEARS ETC. ERROR1 = (3*CENTRY/4)-12 ERROR2 = ((8*CENTRY+5)/25)-5 C LOCATING SUNDAY DAY = (5*YEAR/4)-ERROR1-10 C LOCATING THE EPACT(FULL MOON) EPACT = MOD(11*METCYC+20+ERROR2-ERROR1,30) IF(EPACT.LT.0)EPACT=30+EPACT IF((EPACT.EQ.25.AND.METCYC.GT.11).OR.EPACT.EQ.24)THEN EPACT=EPACT+1 ENDIF ENDIF C FINDING THE FULL MOON LUNA=44-EPACT IF(LUNA.LT.21)THEN LUNA=LUNA+30 ENDIF C LOCATING EASTER SUNDAY LUNA=LUNA+7-(MOD(DAY+LUNA,7)) C LOCATING THE CORRECT MONTH IF(LUNA.GT.31)THEN LUNA = LUNA - 31 PRINT '(A)',' FOR THE YEAR ',YEAR PRINT '(A)',' EASTER FALLS ON APRIL ',LUNA ELSE PRINT '(A)',' FOR THE YEAR ',YEAR PRINT '(A)',' EASTER FALLS ON MARCH ',LUNA ENDIF END Any help would be appreciated, Ken -- WWL 📚