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3127(UNIX)S 3408(\256le)S 3568(protection)S 4005(applies.)S 4375(Thus,)S 4632(the)S 4786(access)S 5112 V 720(list)S 878(is)S 980(useful)S 1259(for)S 1410(restricting)S 1851(the)S 2009(set)S 2156(of)S 2275(people)S 2577(who)S 2785(would)S 3071(otherwise)S 3495(have)S 3719(update)S 4021(permission.)S 4551(Just)S 4743(as)S 4862(with)S 5292 V 720(locking,)S 1077(the)S 1231(access)S 1517(list)S 1672(has)S 1837(no)S 1969(e)S 2013 H (f)show 10 -.5 mul h (f)show 10 R 2074(ect)S 2222(on)S 2354(read-only)S 2768(operations)S 3216(such)S 3431(as)S 10 I 3546(co)S 10 R 3640(.)S 3727(This)S 3937(approach)S 4333(is)S 4431(consistent)S 4862(with)S 5472 V 720(the)S 872(UNIX)S 1151(philosophy)S 1626(of)S 1739(openness,)S 2160(which)S 2434(contributes)S 2908(to)S 3016(a)S 3090(productive)S 3547(software)S 3920(development)S 4466(environment.)S 5832 V 10 B 720(5.)S 855(Con\256guration)S 1486(Management)S 6048 V 10 R 970(The)S 1156(preceding)S 1580(sections)S 1933(described)S 2346(how)S 2549(RCS)S 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2302(release)S 2610(number)S 2947(2)S 3029(from)S 3255(each)S 3469(RCS)S 3691(\256le.)S 3906(This)S 4116(selection)S 4503(is)S 4602(convenient)S 3828 V 970(if)S 1061(a)S 1135(release)S 1441(has)S 1604(been)S 1822(completed)S 2268(and)S 2442(development)S 2988(has)S 3151(moved)S 3453(on)S 3583(to)S 3691(the)S 3843(next)S 4045(release.)S 4224 V 10 I 720(State)S 950(and)S 1130(author)S 1427(based)S 1690(selection)S 4404 V 10 R 970(If)S 1070(the)S 1226(highest)S 1549(level)S 1777(number)S 2116(within)S 2406(a)S 2484(given)S 2740(release)S 3050(number)S 3389(is)S 3490(not)S 3652(the)S 3808(desired)S 4130(one,)S 4333(the)S 4489(state)S 4707(attribute)S 4584 V 970(can)S 1138(help.)S 1395(For)S 1564(example,)S 4764 V 10 I 1330(co)S 1484(\261r2)S 1683(\261sReleased)S 2192(*,v)S 5004 V 10 R 970(retrieves)S 1352(the)S 1513(latest)S 1763(revision)S 2124(with)S 2341(release)S 2656(number)S 3001(2)S 3091(whose)S 3386(state)S 3609(attribute)S 3982(is)S 4089(`Released'.)S 4610(Of)S 4755(course,)S 5184 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2337(of)S 2473(that)S 2676(release,)S 3030(independent)S 3571(of)S 3707(the)S 3882(numbering.)S 4423(The)S 10 I 4631(\261d)S 10 R 4784(option)S 6720 V 970(speci\256es)S 1346(a)S 1422(`cuto)S 1627 H (f)show 10 -.5 mul h (f)show 10 R 1720(date',)S 1976(i.e.,)S 2155(the)S 2309(revision)S 2662(selected)S 3014(has)S 3178(a)S 3253(check-in)S 3627(date)S 3824(that)S 4005(is)S 4103(closest)S 4406(to,)S 4540(but)S 4699(not)S 4858(after)S 6900 V 970(the)S 1122(date)S 1318(given.)S 7116 V 10 I 720(Name)S 983(based)S 1246(selection)S 7296 V 10 R 970(The)S 1178(most)S 1426(powerful)S 1839(selection)S 2247(function)S 2633(is)S 2753(based)S 3033(on)S 3187(assigning)S 3619(symbolic)S 4040(names)S 4349(to)S 4481(revisions)S 4896(and)S 7920 V EP %%Page: 12 13 BP /slant 0 def /height 1.000000 def 10 R 10 R 40 V 0(-)S 580 V 2767(- 12 -)S 900 V 970(branches.)S 1412(In)S 1528(large)S 1760(systems,)S 2135(a)S 2212(single)S 2484(release)S 2793(number)S 3131(or)S 3247(date)S 3446(is)S 3546(not)S 3707(su)S 3796 H (f)show 10 -.5 mul h (\256)show 10 R 3880(cient)S 4107(to)S 4217(collect)S 4515(the)S 4669(appropri-)S 1080 V 970(ate)S 1122(revisions)S 1519(from)S 1749(all)S 1885(groups.)S 2248(For)S 2423(example,)S 2822(suppose)S 3181(one)S 3362(wishes)S 3671(to)S 3786(combine)S 4167(release)S 4480(2)S 4567(of)S 4687(one)S 4868(sub-)S 1260 V 970(system)S 1296(and)S 1488(release)S 1812(15)S 1960(of)S 2091(another.)S 2493(Most)S 2747(likely,)S 3048(the)S 3218(creation)S 3587(dates)S 3840(of)S 3971(those)S 4229(releases)S 4591(di)S 4669 H (f)show 10 -.5 mul h (f)show 10 R 4730(er)S 4854(also.)S 1440 V 970(Thus,)S 1226(a)S 1301(single)S 1571(revision)S 1924(number)S 2260(or)S 2375(date)S 2573(passed)S 2871(to)S 2981(the)S 10 I 3135(co)S 10 R 3261(command)S 3687(will)S 3875(not)S 4035(su)S 4124 H (f)show 10 -.5 mul h (\256)show 10 R 4208(ce)S 4328(to)S 4438(select)S 4697(the)S 4851(right)S 1620 V 970(revisions.)S 1432(Symbolic)S 1862(revision)S 2230(numbers)S 2620(solve)S 2877(this)S 3068(problem.)S 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4874(pro-)S 5784 V 720(cessed)S 1012(is)S 1111(not)S 1271(present,)S 1616(MAKE)S 1942(attempts)S 2313(a)S 2389(check-out)S 2813(operation.)S 3276(If)S 3373(successful,)S 3839(MAKE)S 4164(performs)S 4555(the)S 4708(required)S 5964 V 720(processing,)S 1210(and)S 1392(then)S 1602(deletes)S 1917(the)S 2077(checked)S 2441(out)S 2607(\256le)S 2773(to)S 2889(conserve)S 3281(space.)S 3595(The)S 3788(selection)S 4181(parameters)S 4657(discussed)S 6144 V 720(above)S 996(can)S 1172(be)S 1304(passed)S 1608(to)S 1724(MAKE)S 2056(either)S 2321(as)S 2442(parameters,)S 2942(or)S 3063(directly)S 3406(embedded)S 3854(in)S 3970(the)S 4129(Make\256le.)S 4576(MAKE)S 4907(has)S 6324 V 720(also)S 922(been)S 1152(extended)S 1554(to)S 1674(search)S 1970(the)S 2134(subdirectory)S 2675(named)S 10 I 2983(RCS)S 10 R 3203(for)S 3361(needed)S 3685(\256les,)S 3919(rather)S 4193(than)S 4407(just)S 4594(the)S 4758(current)S 6504 V 720(working)S 1090(directory.)S 1542(However,)S 1969(if)S 2067(a)S 2148(working)S 2517(\256le)S 2681(is)S 2784(present,)S 3133(MAKE)S 3463(totally)S 3755(ignores)S 4085(the)S 4243(corresponding)S 4850(RCS)S 6684 V 720(\256le)S 894(and)S 1085(uses)S 1304(the)S 1473(working)S 1853(\256le.)S 2083(\(In)S 2246(newer)S 2536(versions)S 2916(of)S 3046(MAKE)S 3387(distributed)S 3862(by)S 4009(AT&T)S 4328(and)S 4519(others,)S 4835(auto-)S 6864 V 720(checkout)S 1112(can)S 1282(be)S 1408(achieved)S 1794(with)S 2004(the)S 2158(rule)S 2345(DEFAULT,)S 2856(instead)S 3170(of)S 3284(a)S 3359(special)S 3667(extension)S 4081(of)S 4195(MAKE.)S 4575(However,)S 4996(a)S 6964 V 8 Y1 720(333333333333333333)S 7082 V 8 R 820(*)S 900(This)S 1066(auto-checkout)S 1540(extension)S 1869(is)S 1946(available)S 2256(only)S 2422(in)S 2508(some)S 2700(versions)S 2989(of)S 3079(MAKE,)S 3359(e.g.)S 3498(GNU)S 3696(MAKE.)S 7920 V EP %%Page: 13 14 BP /slant 0 def /height 1.000000 def 8 R 8 R 40 V 10 R 0(-)S 580 V 2767(- 13 -)S 900 V 720(\256le)S 879(checked)S 1236(out)S 1395(by)S 1526(the)S 1679(rule)S 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2379(in)S 2487(the)S 2639(second)S 2946(line,)S 3151(the)S 3303(average)S 3642(number)S 3978(of)S 4092(revisions)S 4484(for)S 4631(those)S 4873(\256les)S 1440 V 720(is)S 823(3.10,)S 1059(with)S 1273(an)S 1403(overhead)S 1804(of)S 1923(1.34.)S 2188(This)S 2401(means)S 2691(that)S 2876(the)S 3033(extra)S 3267(2.10)S 3477(deltas)S 3745(require)S 4062(34)S 4197(per)S 4359(cent)S 4560(extra)S 4794(space,)S 1620 V 720(or)S 842(16)S 981(per)S 1147(cent)S 1352(per)S 1518(extra)S 1756(revision.)S 2172(Rochkind)S 1570 V 2561(3)S 1620 V 2650(measured)S 3071(the)S 3233(space)S 3494(consumed)S 3939(by)S 4079(SCCS,)S 4390(and)S 4574(reported)S 4946(an)S 1800 V 720(average)S 1067(of)S 1188(5)S 1276(revisions)S 1675(per)S 1840(group)S 2111(and)S 2293(an)S 2425(overhead)S 2828(of)S 2949(1.37)S 3162(\(or)S 3316(about)S 3575(9)S 3662(per)S 3826(cent)S 4029(per)S 4193(extra)S 4429(revision\).)S 4876(In)S 4996(a)S 1980 V 720(later)S 930(paper,)S 1209(Glasser)S 1930 V 1508(6)S 1980 V 1591(observed)S 1984(an)S 2111(average)S 2453(of)S 2569(7)S 2652(revisions)S 3046(per)S 3206(group)S 3472(in)S 3583(a)S 3660(single,)S 3957(large)S 4189(project,)S 4524(but)S 4685(provided)S 2160 V 720(no)S 863(overhead)S 1271(\256gure.)S 1602(In)S 1728(his)S 1888(paper)S 2152(on)S 2294(DSEE)S 2110 V 2544(5)S 2160 V 2594(,)S 2661(Leblang)S 3030(reported)S 3404(that)S 3596(delta)S 3832(storage)S 4162(combined)S 4598(with)S 4818(blank)S 2340 V 720(compression)S 1260(results)S 1556(in)S 1669(an)S 1798(overhead)S 2198(of)S 2316(a)S 2395(mere)S 2629(1\2612)S 2814(per)S 2976(cent)S 3177(per)S 3339(revision.)S 3751(Since)S 4009(leading)S 4339(blanks)S 4636(accounted)S 2520 V 720(for)S 870(about)S 1126(20)S 1260(per)S 1421(cent)S 1621(of)S 1738(the)S 1894(surveyed)S 2288(Pascal)S 2577(programs,)S 3013(a)S 3091(revision)S 3447(group)S 3714(with)S 3926(5\26110)S 4159(members)S 4558(was)S 4746(smaller)S 2700 V 720(than)S 922(a)S 996(single)S 1265(cleartext)S 1638(copy.)S 2916 V 970(The)S 1155(above)S 1423(observations)S 1958(demonstrate)S 2476(clearly)S 2777(that)S 2957(the)S 3109(space)S 3360(needed)S 3672(for)S 3818(extra)S 4047(revisions)S 4439(is)S 4537(small.)S 4840(With)S 3096 V 720(delta)S 950(storage,)S 1299(the)S 1457(luxury)S 1753(of)S 1871(keeping)S 2222(multiple)S 2591(revisions)S 2987(online)S 3272(is)S 3374(certainly)S 3758(a)S 3802 H (f)show 10 -.5 mul h (f)show 10 R 3863(ordable.)S 4252(In)S 4370(fact,)S 4579(introducing)S 3276 V 720(a)S 803(system)S 1120(with)S 1337(delta)S 1571(storage)S 1899(may)S 2111(reduce)S 2416(storage)S 2744(requirements,)S 3330(because)S 3685(programmers)S 4257(often)S 4502(save)S 4719(back-up)S 3456 V 720(copies)S 1011(anyway.)S 1411(Since)S 1668(back-up)S 2024(copies)S 2314(are)S 2470(stored)S 2749(much)S 3006(more)S 3246(e)S 3290 H (f)show 10 -.5 mul h (\256)show 10 R 3374(ciently)S 3681(with)S 3894(deltas,)S 4187(introducing)S 4683(a)S 4762(system)S 3636 V 720(such)S 933(as)S 1046(RCS)S 1266(may)S 1468(actually)S 1814(free)S 1998(a)S 2072(considerable)S 2606(amount)S 2936(of)S 3049(space.)S 3996 V 10 B 720(7.)S 855(Survey)S 1185(of)S 1298(Version)S 1661(Control)S 2024(Tools)S 4212 V 10 R 970(The)S 1159(need)S 1381(to)S 1493(keep)S 1715(back-up)S 2070(copies)S 2359(of)S 2477(software)S 2855(arose)S 3100(when)S 3351(programs)S 3763(and)S 3942(data)S 4143(were)S 4371(no)S 4506(longer)S 4796(stored)S 4392 V 720(on)S 861(paper)S 1123(media,)S 1433(but)S 1602(were)S 1836(entered)S 2170(from)S 2405(terminals)S 2818(and)S 3003(stored)S 3288(on)S 3428(disk.)S 3690(Back-up)S 4068(copies)S 4363(are)S 4524(desirable)S 4924(for)S 4572 V 720(reliability,)S 1166(and)S 1342(many)S 1596(modern)S 1934(editors)S 2239(automatically)S 2816(save)S 3026(a)S 3103(back-up)S 3457(copy)S 3684(for)S 3833(every)S 4087(\256le)S 4248(touched.)S 4652(This)S 4863(stra-)S 4752 V 720(tegy)S 928(is)S 1031(valuable)S 1405(for)S 1557(short-term)S 2009(back-ups,)S 2430(but)S 2593(not)S 2756(suitable)S 3102(for)S 3253(long-term)S 3682(version)S 4011(control,)S 4354(since)S 4594(an)S 4723(existing)S 4932 V 720(back-up)S 1071(copy)S 1295(is)S 1392(overwritten)S 1882(whenever)S 2299(the)S 2451(corresponding)S 3052(\256le)S 3210(is)S 3307(edited.)S 5148 V 970(Tape)S 1217(archives)S 1597(are)S 1766(suitable)S 2125(for)S 2289(long-term,)S 2756(o)S 2806 H (f)show 10 -.5 mul h (\257)show 10 R 2890(ine)S 3060(storage.)S 3451(If)S 3565(all)S 3713(changed)S 4093(\256les)S 4308(are)S 4477(dumped)S 4847(on)S 4996(a)S 5328 V 720(back-up)S 1073(tape)S 1271(once)S 1491(per)S 1650(day,)S 1851(old)S 2010(revisions)S 2402(remain)S 2710(accessible.)S 3200(However,)S 3621(tape)S 3818(archives)S 4181(are)S 4333(unsatisfactory)S 4924(for)S 5508 V 720(version)S 1049(control)S 1367(in)S 1480(several)S 1797(ways.)S 2092(First,)S 2337(backing)S 2689(up)S 2825(the)S 2983(\256le)S 3147(system)S 3461(every)S 3718(24)S 3854(hours)S 4112(does)S 4331(not)S 4495(capture)S 4824(inter-)S 5688 V 720(mediate)S 1078(revisions.)S 1536(Secondly,)S 1975(the)S 2139(old)S 2308(revisions)S 2710(are)S 2872(not)S 3041(online,)S 3357(and)S 3542(accessing)S 3965(them)S 4206(is)S 4314(tedious)S 4644(and)S 4829(time-)S 5868 V 720(consuming.)S 1248(In)S 1365(particular,)S 1806(it)S 1896(is)S 1997(impractical)S 2480(to)S 2592(compare)S 2969(several)S 3285(old)S 3447(revisions)S 3843(of)S 3961(a)S 4040(group,)S 4333(because)S 4683(that)S 4868(may)S 6048 V 720(require)S 1037(mounting)S 1456(and)S 1635(searching)S 2052(several)S 2369(tapes.)S 2664(Tape)S 2898(archives)S 3265(are)S 3421(important)S 3845(fail-safe)S 4206(tools)S 4436(in)S 4549(the)S 4706(event)S 4957(of)S 6228 V 720(catastrophic)S 1240(disk)S 1445(failures)S 1782(or)S 1903(accidental)S 2345(deletions,)S 2769(but)S 2935(they)S 3145(are)S 3304(ill-suited)S 3698(for)S 3852(version)S 4184(control.)S 4560(Conversely,)S 6408 V 720(version)S 1044(control)S 1357(tools)S 1582(do)S 1712(not)S 1870(obviate)S 2194(the)S 2346(need)S 2564(for)S 2710(tape)S 2906(archives.)S 6624 V 970(A)S 1076(natural)S 1387(technique)S 1809(for)S 1959(keeping)S 2309(several)S 2625(old)S 2787(revisions)S 3182(online)S 3466(is)S 3567(to)S 3679(never)S 3934(delete)S 4206(a)S 4285(\256le.)S 4503(Editing)S 4833(a)S 4912(\256le)S 6804 V 720(simply)S 1036(creates)S 1355(a)S 1442(new)S 1651(\256le)S 1822(with)S 2043(the)S 2208(same)S 2456(name,)S 2740(but)S 2911(with)S 3132(a)S 3218(di)S 3296 H (f)show 10 -.5 mul h (f)show 10 R 3357(erent)S 3598(sequence)S 4005(number.)S 4407(This)S 4627(technique,)S 6984 V 720(available)S 1119(as)S 1241(an)S 1374(option)S 1669(in)S 1786(DEC's)S 2097(VMS)S 2353(operating)S 2769(system,)S 3111(turns)S 3350(out)S 3518(to)S 3636(be)S 3770(inadequate)S 4242(for)S 4398(version)S 4732(control.)S 7164 V 720(First,)S 970(it)S 1067(is)S 1174(prohibitively)S 1731(expensive)S 2170(in)S 2288(terms)S 2550(of)S 2673(storage)S 3001(costs,)S 3266(especially)S 3705(since)S 3950(no)S 4090(data)S 4296(compression)S 4841(tech-)S 7344 V 720(niques)S 1016(are)S 1172(employed.)S 1656(Secondly,)S 2088(indiscriminately)S 2773(storing)S 3086(every)S 3342(change)S 3659(produces)S 4054(too)S 4217(many)S 4474(revisions,)S 4896(and)S 7920 V EP %%Page: 16 17 BP /slant 0 def /height 1.000000 def 10 R 10 R 40 V 0(-)S 580 V 2767(- 16 -)S 900 V 720(programmers)S 1289(have)S 1514(di)S 1592 H (f)show 10 -.5 mul h (\256)show 10 R 1676(culties)S 1974(distinguishing)S 2579(them.)S 2871(The)S 3063(proliferation)S 3599(of)S 3718(revisions)S 4115(forces)S 4394(programmers)S 4962(to)S 1080 V 720(spend)S 989(much)S 1247(time)S 1461(on)S 1597(\256nding)S 1917(and)S 2097(deleting)S 2455(useless)S 2774(\256les.)S 3032(Thirdly,)S 3393(most)S 3624(of)S 3743(the)S 3902(support)S 4239(functions)S 4648(like)S 4835(lock-)S 1260 V 720(ing,)S 903(logging,)S 1264(revision)S 1616(selection,)S 2026(and)S 2200(identi\256cation)S 2758(described)S 3170(in)S 3278(this)S 3453(paper)S 3704(are)S 3855(not)S 4013(available.)S 1476 V 970(An)S 1122(alternative)S 1573(approach)S 1968(is)S 2065(to)S 2173(separate)S 2529(editing)S 2837(from)S 3061(revision)S 3414(control.)S 3783(The)S 3969(user)S 4166(may)S 4369(repeatedly)S 4815(edit)S 4996(a)S 1656 V 720(given)S 985(revision,)S 1374(until)S 1600(freezing)S 1968(it)S 2066(with)S 2286(an)S 2422(explicit)S 2764(command.)S 3255(Once)S 3507(a)S 3593(revision)S 3957(is)S 4066(frozen,)S 4387(it)S 4485(is)S 4594(stored)S 4880(per-)S 1836 V 720(manently)S 1122(and)S 1296(can)S 1464(no)S 1594(longer)S 1879(be)S 2003(modi\256ed.)S 2445(\(In)S 2592(RCS,)S 2838(freezing)S 3195(a)S 3270(revisions)S 3662(is)S 3760(done)S 3985(with)S 10 I 4194(ci)S 10 R 4266(.\))S 4385(Editing)S 4711(a)S 4786(frozen)S 2016 V 720(revision)S 1073(implicitly)S 1494(creates)S 1801(a)S 1876(new)S 2073(one,)S 2273(which)S 2548(can)S 2717(again)S 2964(be)S 3089(changed)S 3451(repeatedly)S 3896(until)S 4110(it)S 4196(is)S 4293(frozen)S 4577(itself.)S 4862(This)S 2196 V 720(approach)S 1123(saves)S 1377(exactly)S 1703(those)S 1952(revisions)S 2352(that)S 2541(the)S 2702(user)S 2907(considers)S 3323(important,)S 3776(and)S 3959(keeps)S 4225(the)S 4386(number)S 4730(of)S 4852(revi-)S 2376 V 720(sions)S 969(manageable.)S 1543(IBM's)S 1847(CLEAR/CASTER)S 2326 V 2587(7)S 2376 V 2637(,)S 2705(AT&T's)S 3092(SCCS)S 2326 V 3338(3)S 2376 V 3388(,)S 3456(CMU's)S 3799(SDC)S 2326 V 3994(8)S 2376 V 4087(and)S 4274(DEC's)S 4589(CMS)S 2326 V 4801(9)S 2376 V 4851(,)S 4919(are)S 2556 V 720(examples)S 1142(of)S 1270(version)S 1609(control)S 1937(systems)S 2299(using)S 2561(this)S 2751(approach.)S 3216(CLEAR/CASTER)S 4001(maintains)S 4435(a)S 4524(data)S 4735(base)S 4957(of)S 2736 V 720(programs,)S 1163(speci\256cations,)S 1773(documentation)S 2407(and)S 2591(messages,)S 3033(using)S 3290(deltas.)S 3618(Its)S 3758(goal)S 3970(is)S 4077(to)S 4195(provide)S 4540(control)S 4863(over)S 2916 V 720(the)S 873(development)S 1420(process)S 1750(from)S 1975(a)S 2050(management)S 2591(viewpoint.)S 3077(SCCS)S 3354(stores)S 3618(multiple)S 3983(revisions)S 4375(of)S 4489(source)S 4780(text)S 4962(in)S 3096 V 720(an)S 861(ancestral)S 1262(tree,)S 1483(records)S 1823(a)S 1913(log)S 2087(entry)S 2338(for)S 2500(each)S 2728(revision,)S 3121(provides)S 3511(access)S 3811(control,)S 4165(and)S 4355(has)S 4534(facilities)S 4924(for)S 3276 V 720(uniquely)S 1100(identifying)S 1569(each)S 1781(revision.)S 2188(An)S 2340(e)S 2384 H (f)show 10 -.5 mul h (\256)show 10 R 2468(cient)S 2692(delta)S 2916(technique)S 3334(reduces)S 3668(the)S 3820(space)S 4072(consumed)S 4508(by)S 4639(each)S 4852(revi-)S 3456 V 720(sion)S 919(group.)S 1239(SDC)S 1466(is)S 1565(much)S 1819(simpler)S 2151(than)S 2355(SCCS)S 2633(because)S 2980(it)S 3068(stores)S 3333(not)S 3493(more)S 3730(than)S 3934(two)S 4116(revisions.)S 4563(However,)S 4984(it)S 3636 V 720(maintains)S 1140(a)S 1215(complete)S 1612(log)S 1771(for)S 1918(all)S 2049(old)S 2208(revisions,)S 2625(some)S 2867(of)S 2981(which)S 3256(may)S 3459(be)S 3584(on)S 3715(back-up)S 4067(tape.)S 4319(CMS,)S 4587(like)S 4769(SCCS,)S 3816 V 720(manages)S 1099(tree-structured)S 1710(revision)S 2062(groups,)S 2389(but)S 2547(o)S 2597 H (f)show 10 -.5 mul h (f)show 10 R 2658(ers)S 2804(no)S 2934(identi\256cation)S 3492(mechanism.)S 4032 V 970(Tools)S 1228(for)S 1374(dealing)S 1698(with)S 1906(con\256gurations)S 2508(are)S 2659(still)S 2841(in)S 2950(a)S 3025(state)S 3239(of)S 3353(\257ux.)S 3595(SCCS,)S 3897(SDC)S 4123(and)S 4298(CMS)S 4541(can)S 4710(be)S 4835(com-)S 4212 V 720(bined)S 988(with)S 1211(MAKE)S 1550(or)S 1678(MAKE-like)S 2200(programs.)S 2677(Since)S 2944(\257exible)S 3289(selection)S 3689(rules)S 3928(are)S 4094(missing)S 4451(from)S 4690(all)S 4835(these)S 4392 V 720(tools,)S 986(it)S 1088(is)S 1201(sometimes)S 1675(di)S 1753 H (f)show 10 -.5 mul h (\256)show 10 R 1837(cult)S 2033(to)S 2157(specify)S 2491(precisely)S 2897(which)S 3187(revision)S 3555(of)S 3685(each)S 3914(group)S 4194(should)S 4508(be)S 4649(passed)S 4962(to)S 4572 V 720(MAKE)S 1055(for)S 1211(building)S 1585(a)S 1669(desired)S 1997(con\256guration.)S 2625(The)S 2820(Xerox)S 3109(Cedar)S 3387(system)S 4522 V 3665(10)S 4572 V 3805(provides)S 4189(a)S 4273(`System)S 4641(Modeller')S 4752 V 720(that)S 903(can)S 1074(rebuild)S 1390(a)S 1467(con\256guration)S 2033(from)S 2260(an)S 2387(arbitrary)S 2763(set)S 2907(of)S 3023(module)S 3356(revisions.)S 3806(The)S 3995(revisions)S 4390(of)S 4507(a)S 4585(module)S 4919(are)S 4932 V 720(only)S 935(distinguished)S 1506(by)S 1643(creation)S 2001(time,)S 2241(and)S 2422(there)S 2658(is)S 2762(no)S 2899(tool)S 3092(for)S 3245(managing)S 3676(groups.)S 4039(Since)S 4297(the)S 4455(selection)S 4846(rules)S 5112 V 720(are)S 871(primitive,)S 1293(the)S 1445(System)S 1770(Modeller)S 2166(appears)S 2500(to)S 2608(be)S 2732(somewhat)S 3167(tedious)S 3486(to)S 3594(use.)S 3812(Apollo's)S 4192(DSEE)S 5062 V 4442(5)S 5112 V 4522(is)S 4620(a)S 4695(sophisti-)S 5292 V 720(cated)S 961(software)S 1335(engineering)S 1837(environment.)S 2428(It)S 2520(manages)S 2900(revision)S 3253(groups)S 3556(in)S 3665(a)S 3740(way)S 3937(similar)S 4245(to)S 4353(SCCS)S 4629(and)S 4803(CMS.)S 5472 V 720(Con\256gurations)S 1359(are)S 1524(built)S 1752(using)S 2013(`con\256guration)S 2624(threads'.)S 3045(A)S 3162(con\256guration)S 3740(thread)S 4034(states)S 4301(which)S 4590(revision)S 4957(of)S 5652 V 720(each)S 947(group)S 1225(named)S 1536(in)S 1659(a)S 1748(con\256guration)S 2326(should)S 2638(be)S 2777(chosen.)S 3154(A)S 3271(con\256guration)S 3849(thread)S 4142(may)S 4358(contain)S 4696(dynamic)S 5832 V 720(speci\256ers)S 1141(\(e.g.,)S 1387(`choose)S 1741(the)S 1908(revisions)S 2314(I)S 2392(am)S 2559(currently)S 2964(working)S 3342(on,)S 3512(and)S 3701(the)S 3868(most)S 4108(recent)S 4396(revisions)S 4802(other-)S 6012 V 720(wise'\),)S 1030(which)S 1310(are)S 1467(bound)S 1753(automatically)S 2332(at)S 2439(build)S 2680(time.)S 2948(It)S 3044(also)S 3240(provides)S 3619(a)S 3698(noti\256cation)S 4189(mechanism)S 4679(for)S 4830(alert-)S 6192 V 720(ing)S 878(maintainers)S 1374(about)S 1626(the)S 1778(need)S 1996(to)S 2104(rebuild)S 2417(a)S 2491(system)S 2799(after)S 3011(a)S 3085(change.)S 6408 V 970(RCS)S 1195(is)S 1298(based)S 1561(on)S 1697(a)S 1777(general)S 2106(model)S 2392(for)S 2544(describing)S 2996(multi-version/multi-con\256guration)S 4377(systems)S 6358 V 4694(11)S 6408 V 4794(.)S 4885(The)S 6588 V 720(model)S 1017(describes)S 1435(systems)S 1798(using)S 2061(AND/OR)S 2490(graphs,)S 2827(where)S 3116(AND)S 3378(nodes)S 3657(represent)S 4068(con\256gurations,)S 4711(and)S 4901(OR)S 6768 V 720(nodes)S 1012(represent)S 1436(version)S 1789(groups.)S 2175(The)S 2389(model)S 2698(gives)S 2968(rise)S 3171(to)S 3308(a)S 3411(suit)S 3615(of)S 3757(selection)S 4171(rules)S 4425(for)S 4601(composing)S 6948 V 720(con\256gurations,)S 1354(almost)S 1658(all)S 1795(of)S 1915(which)S 2196(are)S 2354(implemented)S 2913(in)S 3028(RCS.)S 3310(The)S 3501(revisions)S 3898(selected)S 4255(by)S 4391(RCS)S 4617(are)S 4774(passed)S 7128 V 720(to)S 831(MAKE)S 1158(for)S 1307(con\256guration)S 1873(building.)S 2295(Revision)S 2684(group)S 2950(management)S 3493(is)S 3593(modelled)S 3999(after)S 4215(SCCS.)S 4550(RCS)S 4774(retains)S 7308 V 720(SCCS's)S 1080(best)S 1283(features,)S 1665(but)S 1835(o)S 1885 H (f)show 10 -.5 mul h (f)show 10 R 1946(ers)S 2104(a)S 2190(signi\256cantly)S 2727(simpler)S 3068(user)S 3275(interface,)S 3689(\257exible)S 4030(selection)S 4426(rules,)S 4686(adequate)S 7920 V EP %%Page: 17 18 BP /slant 0 def /height 1.000000 def 10 R 10 R 40 V 0(-)S 580 V 2767(- 17 -)S 900 V 720(integration)S 1190(with)S 1405(MAKE)S 1736(and)S 1917(improved)S 2337(identi\256cation.)S 2957(A)S 3066(detailed)S 3419(comparison)S 3922(of)S 4042(RCS)S 4270(and)S 4452(SCCS)S 4736(appears)S 1080 V 720(in)S 828(Reference)S 1261(4.)S 1296 V 970(An)S 1126(important)S 1549(component)S 2027(of)S 2144(all)S 2278(revision)S 2634(control)S 2951(systems)S 3303(is)S 3405(a)S 3484(program)S 3857(for)S 4008(computing)S 4471(deltas.)S 4794(SCCS)S 1476 V 720(and)S 896(RCS)S 1118(use)S 1283(the)S 1437(program)S 10 I 1807(diff)S 1426 V 10 R 1941(2)S 1476 V 1991(,)S 2048(which)S 2324(\256rst)S 2512(computes)S 2927(the)S 3081(longest)S 3402(common)S 3784(substring)S 4183(of)S 4298(two)S 4479(revisions,)S 4896(and)S 1656 V 720(then)S 927(produces)S 1322(the)S 1479(delta)S 1708(from)S 1937(that)S 2122(substring.)S 2579(The)S 2769(delta)S 2998(is)S 3100(simply)S 3408(an)S 3537(edit)S 3722(script)S 3979(consisting)S 4420(of)S 4538(deletion)S 4896(and)S 1836 V 720(insertion)S 1100(commands)S 1563(that)S 1743(generate)S 2110(one)S 2284(revision)S 2636(from)S 2860(the)S 3012(other.)S 2052 V 970(A)S 1078(delta)S 1308(based)S 1571(on)S 1707(a)S 1787(longest)S 2112(common)S 2498(substring)S 2901(is)S 3004(not)S 3168(necessarily)S 3648(minimal,)S 4044(because)S 4396(it)S 4489(does)S 4709(not)S 4874(take)S 2232 V 720(advantage)S 1156(of)S 1271(crossing)S 1636(block)S 1890(moves.)S 2238(Crossing)S 2626(block)S 2880(moves)S 3173(arise)S 3392(if)S 3484(two)S 3665(or)S 3779(more)S 4015(blocks)S 4307(of)S 4421(lines)S 4641(\(e.g.,)S 4874(pro-)S 2412 V 720(cedures\))S 1090(appear)S 1388(in)S 1499(a)S 1576(di)S 1654 H (f)show 10 -.5 mul h (f)show 10 R 1715(erent)S 1947(order)S 2190(in)S 2301(two)S 2484(revisions.)S 2933(An)S 3088(edit)S 3271(script)S 3526(derived)S 3858(from)S 4085(a)S 4162(longest)S 4484(common)S 4868(sub-)S 2592 V 720(string)S 987(\256rst)S 1182(deletes)S 1498(the)S 1659(shorter)S 1975(of)S 2097(the)S 2258(two)S 2447(blocks,)S 2772(and)S 2955(then)S 3166(reinserts)S 3543(it.)S 3693(Heckel)S 2542 V 3975(12)S 2592 V 4114(proposed)S 4519(an)S 4651(algorithm)S 2772 V 720(for)S 884(detecting)S 1298(block)S 1568(moves,)S 1902(but)S 2078(since)S 2331(the)S 2501(algorithm)S 2938(is)S 3053(based)S 3328(on)S 3476(heuristics,)S 3932(there)S 4179(are)S 4348(conditions)S 4813(under)S 2952 V 720(which)S 997(the)S 1152(generated)S 1572(delta)S 1799(is)S 1899(far)S 2042(from)S 2269(minimal.)S 2691(DSEE)S 2974(uses)S 3179(this)S 3357(algorithm)S 3779(combined)S 4205(with)S 4415(blank)S 4669(compres-)S 3132 V 720(sion,)S 965(apparently)S 1439(with)S 1670(satisfactory)S 2183(overall)S 2514(results.)S 2884(A)S 3010(new)S 3230(algorithm)S 3673(that)S 3877(is)S 3998(guaranteed)S 4489(to)S 4621(produce)S 4996(a)S 3312 V 720(minimal)S 1085(delta)S 1310(based)S 1568(on)S 1699(block)S 1951(moves)S 2242(appears)S 2576(in)S 2684(Reference)S 3117(13.)S 3302(A)S 3404(future)S 3672(release)S 3978(of)S 4091(RCS)S 4311(will)S 4497(use)S 4660(this)S 4835(algo-)S 3492 V 720(rithm.)S 3708 V 10 I 970(Acknowledgements)S 10 R 1735(:)S 1818(Many)S 2106(people)S 2427(have)S 2670(helped)S 2991(make)S 3262(RCS)S 3507(a)S 3606(success)S 3960(by)S 4115(contributed)S 4626(criticisms,)S 3888 V 720(suggestions,)S 1246(corrections,)S 1748(and)S 1926(even)S 2148(whole)S 2426(new)S 2626(commands)S 3093(\(including)S 3538(manual)S 3866(pages\).)S 4214(The)S 4402(list)S 4558(of)S 4674(people)S 4973(is)S 4068 V 720(too)S 878(long)S 1086(to)S 1194(be)S 1318(reproduced)S 1796(here,)S 2022(but)S 2180(my)S 2338(sincere)S 2650(thanks)S 2941(for)S 3087(their)S 3300(help)S 3502(and)S 3676(goodwill)S 4062(goes)S 4275(to)S 4383(all)S 4513(of)S 4626(them.)S 4488 V 10 B 720(Appendix:)S 1201(Synopsis)S 1605(of)S 1718(RCS)S 1948(Operations)S 4680 V 10 I 720(ci)S 10 B 822(\261)S 902(check)S 1176(in)S 1290(revisions)S 4800 V 10 I 970(Ci)S 10 R 1102(stores)S 1372(the)S 1531(contents)S 1901(of)S 2021(a)S 2102(working)S 2472(\256le)S 2637(into)S 2830(the)S 2989(corresponding)S 3598(RCS)S 3826(\256le)S 3992(as)S 4113(a)S 4195(new)S 4399(revision.)S 4814(If)S 4918(the)S 4920 V 970(RCS)S 1191(\256le)S 1350(doesn't)S 1675(exist,)S 10 I 1920(ci)S 10 R 2023(creates)S 2330(it.)S 10 I 2472(Ci)S 10 R 2598(removes)S 2967(the)S 3120(working)S 3484(\256le,)S 3668(unless)S 3949(one)S 4124(of)S 4238(the)S 4391(options)S 10 I 4717(\261u)S 10 R 4848(or)S 10 I 4962(\261l)S 5040 V 10 R 970(is)S 1071(present.)S 1448(For)S 1621(each)S 1837(check-in,)S 10 I 2239(ci)S 10 R 2345(asks)S 2551(for)S 2701(a)S 2779(commentary)S 3312(describing)S 3763(the)S 3920(changes)S 4276(relative)S 4610(to)S 4723(the)S 4880(pre-)S 5160 V 970(vious)S 1217(revision.)S 5400 V 10 I 970(Ci)S 10 R 1111(assigns)S 1446(the)S 1614(revision)S 1982(number)S 2333(given)S 2601(by)S 2747(the)S 10 I 2915(\261r)S 10 R 3050(option;)S 3380(if)S 3487(that)S 3683(option)S 3985(is)S 4098(missing,)S 4481(it)S 4583(derives)S 4918(the)S 5520 V 970(number)S 1313(from)S 1545(the)S 1705(lock)S 1915(held)S 2125(by)S 2263(the)S 2423(user;)S 2655(if)S 2754(there)S 2991(is)S 3096(no)S 3234(lock)S 3444(and)S 3625(locking)S 3962(is)S 4066(not)S 4231(strict,)S 10 I 4493(ci)S 10 R 4602(increments)S 5640 V 970(the)S 1136(number)S 1485(of)S 1612(the)S 1778(latest)S 2033(revision)S 2399(on)S 2544(the)S 2711(trunk.)S 3022(A)S 3139(side)S 3345(branch)S 3661(can)S 3844(only)S 4067(be)S 4206(started)S 4517(by)S 4662(explicitly)S 5760 V 970(specifying)S 1416(its)S 1541(number)S 1876(with)S 2084(the)S 10 I 2236(\261r)S 10 R 2355(option)S 2641(during)S 2932(check-in.)S 6000 V 10 I 970(Ci)S 10 R 1106(also)S 1308(determines)S 1787(whether)S 2149(the)S 2312(revision)S 2675(to)S 2794(be)S 2929(checked)S 3296(in)S 3415(is)S 3523(di)S 3601 H (f)show 10 -.5 mul h (f)show 10 R 3662(erent)S 3902(from)S 4137(the)S 4300(previous)S 4685(one,)S 4896(and)S 6120 V 970(asks)S 1194(whether)S 1567(to)S 1697(proceed)S 2064(if)S 2177(not.)S 2412(This)S 2642(facility)S 2977(simpli\256es)S 3419(check-in)S 3814(operations)S 4281(for)S 4448(large)S 4698(systems,)S 6240 V 970(because)S 1315(one)S 1489(need)S 1707(not)S 1865(remember)S 2299(which)S 2573(\256les)S 2770(were)S 2993(changed.)S 6480 V 970(The)S 1161(option)S 10 I 1453(\261k)S 10 R 1583(searches)S 1956(the)S 2114(checked)S 2476(in)S 2590(\256le)S 2754(for)S 2906(identi\256cation)S 3470(markers)S 3827(containing)S 4285(the)S 4443(attributes)S 4852(revi-)S 6600 V 970(sion)S 1169(number,)S 1530(check-in)S 1904(date,)S 2126(author)S 2412(and)S 2587(state,)S 2826(and)S 3001(assigns)S 3321(these)S 3557(to)S 3666(the)S 3819(new)S 4016(revision)S 4369(rather)S 4632(than)S 4835(com-)S 6720 V 970(puting)S 1275(them.)S 1579(This)S 1806(option)S 2111(is)S 2227(useful)S 2520(for)S 2685(software)S 3077(distribution:)S 3616(Recipients)S 4087(of)S 4219(distributed)S 4697(software)S 6840 V 970(using)S 1227(RCS)S 1457(should)S 1764(check)S 2036(in)S 2154(updates)S 2499(with)S 2717(the)S 10 I 2879(\261k)S 10 R 3013(option.)S 3364(This)S 3581(convention)S 4064(guarantees)S 4529(that)S 4718(revision)S 6960 V 970(numbers,)S 1369(check-in)S 1742(dates,)S 2002(etc.,)S 2198(are)S 2349(the)S 2501(same)S 2736(at)S 2838(all)S 2968(sites.)S 7116 V 10 I 720(co)S 10 B 844(\261)S 924(check)S 1198(out)S 1367(revisions)S 7236 V 10 I 970(Co)S 10 R 1136(retrieves)S 1528(revisions)S 1938(according)S 2380(to)S 2507(revision)S 2878(number,)S 3257(date,)S 3497(author)S 3801(and)S 3994(state)S 4226(attributes.)S 4702(It)S 4813(either)S 7920 V EP %%Page: 18 19 BP /slant 0 def /height 1.000000 def 10 R 10 R 40 V 0(-)S 520 V 2767(- 18 -)S 840 V 970(places)S 1251(the)S 1405(revision)S 1759(into)S 1947(the)S 2101(working)S 2465(\256le,)S 2649(or)S 2763(prints)S 3022(it)S 3109(on)S 3240(the)S 3393(standard)S 3762(output.)S 10 I 4104(Co)S 10 R 4252(always)S 4560(expands)S 4918(the)S 960 V 970(identi\256cation)S 1528(markers.)S 1116 V 10 I 720(ident)S 10 B 950(\261)S 1030(extract)S 1358(identi\256cation)S 1950(markers)S 1236 V 10 I 970(Ident)S 10 R 1205(extracts)S 1545(the)S 1697(identi\256cation)S 2255(markers)S 2606(expanded)S 3018(by)S 10 I 3148(co)S 10 R 3272(from)S 3496(any)S 3670(\256le)S 3828(and)S 4002(prints)S 4260(them.)S 1392 V 10 I 720(rcs)S 10 B 872(\261)S 952(change)S 1282(RCS)S 1512(\256le)S 1670(attributes)S 1512 V 10 I 970(Rcs)S 10 R 1144(is)S 1241(an)S 1365(administrative)S 1967(operation)S 2374(that)S 2554(changes)S 2905(access)S 3189(lists,)S 3406(locks,)S 3673(unlocks,)S 4040(breaks)S 4331(locks,)S 4598(toggles)S 4918(the)S 1632 V 970(strict-locking)S 1541(feature,)S 1880(sets)S 2068(state)S 2289(attributes)S 2699(and)S 2881(symbolic)S 3286(revision)S 3646(numbers,)S 4053(changes)S 4412(the)S 4571(description,)S 1752 V 970(and)S 1144(deletes)S 1451(revisions.)S 1897(A)S 1999(revision)S 2351(can)S 2519(only)S 2727(be)S 2851(deleted)S 3169(if)S 3260(it)S 3346(is)S 3443(not)S 3601(the)S 3753(fork)S 3949(of)S 4062(a)S 4136(side)S 4327(branch.)S 1908 V 10 I 720(rcsclean)S 10 B 1088(\261)S 1168(clean)S 1420(working)S 1806(directory)S 2028 V 10 I 970(Rcsclean)S 10 R 1360(removes)S 1728(working)S 2091(\256les)S 2288(that)S 2468(were)S 2691(checked)S 3047(out)S 3205(but)S 3363(never)S 3614(changed.*)S 2184 V 10 I 720(rcsdiff)S 10 B 1006(\261)S 1086(compare)S 1487(revisions)S 2304 V 10 I 970(Rcsdiff)S 10 R 1289(compares)S 1712(two)S 1903(revisions)S 2305(and)S 2490(prints)S 2759(their)S 2983(di)S 3061 H (f)show 10 -.5 mul h (f)show 10 R 3122(erence,)S 3447(using)S 3705(the)S 3868(UNIX)S 4158(tool)S 10 I 4355(diff)S 10 R 4489(.)S 4585(One)S 4793(of)S 4918(the)S 2424 V 970(revisions)S 1361(compared)S 1784(may)S 1986(be)S 2110(checked)S 2466(out.)S 2679(This)S 2887(command)S 3311(is)S 3408(useful)S 3682(for)S 3828(\256nding)S 4142(out)S 4300(about)S 4552(changes.)S 2580 V 10 I 720(rcsfreeze)S 10 B 1110(\261)S 1190(freeze)S 1473(a)S 1553(con\256guration)S 2700 V 10 I 970(Rcsfreeze)S 10 R 1394(assigns)S 1726(the)S 1891(same)S 2139(symbolic)S 2549(revision)S 2914(number)S 3262(to)S 3383(a)S 3470(given)S 3735(revision)S 4100(in)S 4221(all)S 4364(RCS)S 4597(\256les.)S 4862(This)S 2820 V 970(command)S 1394(is)S 1491(useful)S 1765(for)S 1911(accurately)S 2350(recording)S 2762(a)S 2836(con\256guration.*)S 2976 V 10 I 720(rcsmerge)S 10 B 1121(\261)S 1201(merge)S 1496(revisions)S 3096 V 10 I 970(Rcsmerge)S 10 R 1400(merges)S 1725(two)S 1912(revisions,)S 10 I 2335(rev1)S 10 R 2549(and)S 10 I 2730(rev2)S 10 R 2907(,)S 2969(with)S 3184(respect)S 3504(to)S 3620(a)S 3702(common)S 4090(ancestor.)S 4515(A)S 4625(3-way)S 4912(\256le)S 3216 V 970(comparison)S 1472(determines)S 1946(the)S 2104(segments)S 2512(of)S 2631(lines)S 2856(that)S 3042(are)S 3199(\(a\))S 3345(the)S 3503(same)S 3744(in)S 3858(all)S 3994(three)S 4228(revisions,)S 4649(or)S 4767(\(b\))S 4918(the)S 3336 V 970(same)S 1216(in)S 1336(2)S 1428(revisions,)S 1856(or)S 1981(\(c\))S 2133(di)S 2211 H (f)show 10 -.5 mul h (f)show 10 R 2272(erent)S 2513(in)S 2633(all)S 2775(three.)S 3071(For)S 3252(all)S 3394(segments)S 3808(of)S 3933(type)S 4147(\(b\))S 4305(where)S 10 I 4590(rev1)S 10 R 4809(is)S 4918(the)S 3456 V 970(di)S 1048 H (f)show 10 -.5 mul h (f)show 10 R 1109(ering)S 1350(revision,)S 1733(the)S 1891(segment)S 2260(in)S 10 I 2374(rev1)S 10 R 2587(replaces)S 2949(the)S 3107(corresponding)S 3713(segment)S 4081(of)S 10 I 4199(rev2)S 10 R 4376(.)S 4466(Type)S 4706(\(c\))S 4851(indi-)S 3576 V 970(cates)S 1215(an)S 1355(overlapping)S 1878(change,)S 2231(is)S 2344(\257agged)S 2684(as)S 2813(an)S 2953(error,)S 3217(and)S 3408(requires)S 3776(user)S 3989(intervention)S 4519(to)S 4644(select)S 4918(the)S 3696 V 970(correct)S 1276(alternative.)S 3852 V 10 I 720(rlog)S 10 B 917(\261)S 997(read)S 1221(log)S 1379(messages)S 3972 V 10 I 970(Rlog)S 10 R 1189(prints)S 1447(the)S 1599(log)S 1757(messages)S 2164(and)S 2338(other)S 2573(information)S 3075(in)S 3183(an)S 3307(RCS)S 3527(\256le.)S 6962 V 8 Y1 720(333333333333333333)S 7080 V 8 R 820(*)S 900(The)S 8 I 1048(rcsclean)S 8 R 1341(and)S 8 I 1480(rcsfreeze)S 8 R 1790(commands)S 2159(are)S 2279(optional)S 2564(and)S 2703(are)S 2823(not)S 2949(always)S 3194(installed.)S 7920 V EP %%Page: 19 20 BP /slant 0 def /height 1.000000 def 8 R 8 R 40 V 10 R 0(-)S 520 V 2767(- 19 -)S 840 V 10 B 720(References)S 1032 V 10 R 720(1.)S 970(Feldman,)S 1378(Stuart)S 1650(I.,)S 1766(``Make\320A)S 2264(Program)S 2642(for)S 2792(Maintaining)S 3315(Computer)S 3749(Programs,'')S 10 I 4257(Software\320Practice)S 1152 V 970(&)S 1078(Experience)S 10 R 1526(,)S 1581(vol.)S 1764(9,)S 1869(no.)S 2024(3,)S 2129(pp.)S 2284(255-265,)S 2672(March)S 2962(1979.)S 1308 V 720(2.)S 970(Hunt,)S 1229(James)S 1507(W.)S 1660(and)S 1838(McIlroy,)S 2224(M.)S 2372(D.,)S 2528(``An)S 2750(Algorithm)S 3201(for)S 3351(Di)S 3451 H (f)show 10 -.5 mul h (f)show 10 R 3512(erential)S 3846(File)S 4037(Comparison,'')S 4652(41,)S 4812(Com-)S 1428 V 970(puting)S 1256(Science)S 1596(Technical)S 2019(Report,)S 2346(Bell)S 2543(Laboratories,)S 3102(June)S 3315(1976.)S 1584 V 720(3.)S 970(Rochkind,)S 1414(Marc)S 1654(J.,)S 1773(``The)S 2024(Source)S 2331(Code)S 2572(Control)S 2908(System,'')S 10 I 3324(IEEE)S 3570(Transactions)S 4123(on)S 4254(Software)S 4641(Engineer-)S 1704 V 970(ing)S 10 R 1098(,)S 1153(vol.)S 1336(SE-1,)S 1591(no.)S 1746(4,)S 1851(pp.)S 2006(364-370,)S 2394(Dec.)S 2609(1975.)S 1860 V 720(4.)S 970(Tichy,)S 1275(Walter)S 1593(F.,)S 1746(``Design,)S 2168(Implementation,)S 2874(and)S 3066(Evaluation)S 3547(of)S 3678(a)S 3770(Revision)S 4174(Control)S 4528(System,'')S 4962(in)S 1980 V 10 I 970(Proceedings)S 1503(of)S 1615(the)S 1771(6th)S 1933(International)S 2495(Conference)S 2989(on)S 3123(Software)S 3512(Engineering)S 10 R 4006(,)S 4064(pp.)S 4222(58-67,)S 4513(ACM,)S 4799(IEEE,)S 2100 V 970(IPS,)S 1170(NBS,)S 1420(September)S 1877(1982.)S 2256 V 720(5.)S 970(Leblang,)S 1357(David)S 1636(B.)S 1763(and)S 1942(Chase,)S 2247(Robert)S 2555(P.,)S 2697(``Computer-Aided)S 3476(Software)S 3872(Engineering)S 4396(in)S 4510(a)S 4590(Distributed)S 2376 V 970(Workstation)S 1505(Environment,'')S 10 I 2159(SIGPLAN)S 2600(Notices)S 10 R 2900(,)S 2966(vol.)S 3160(19,)S 3325(no.)S 3490(5,)S 3605(pp.)S 3770(104-112,)S 4168(May)S 4391(1984.)S 4686(Proceed-)S 2496 V 970(ings)S 1184(of)S 1314(the)S 1484(ACM)S 1760(SIGSOFT/SIGPLAN)S 2664(Software)S 3072(Engineering)S 3608(Symposium)S 4135(on)S 4283(Practical)S 4680(Software)S 2616 V 970(Development)S 1538(Environments.)S 2772 V 720(6.)S 970(Glasser,)S 1325(Alan)S 1551(L.,)S 1694(``The)S 1947(Evolution)S 2374(of)S 2489(a)S 2565(Source)S 2874(Code)S 3117(Control)S 3455(System,'')S 10 I 3873(Software)S 4261(Engineering)S 4787(Notes)S 10 R 5015(,)S 2892 V 970(vol.)S 1180(3,)S 1312(no.)S 1494(5,)S 1626(pp.)S 1808(122-125,)S 2223(Nov.)S 2477(1978.)S 2789(Proceedings)S 3334(of)S 3474(the)S 3653(Software)S 4069(Quality)S 4425(and)S 4625(Assurance)S 3012 V 970(Workshop.)S 3168 V 720(7.)S 970(Brown,)S 1297(H.B.,)S 1541(``The)S 1792(Clear/Caster)S 2321(System,'')S 10 I 2737(Nato)S 2962(Conference)S 3452(on)S 3582(Software)S 3968(Engineering,)S 4517(Rome)S 10 R 4744(,)S 4799(1970.)S 3324 V 720(8.)S 970(Habermann,)S 1493(A.)S 1623(Nico,)S 10 I 1875(A)S 1969(Software)S 2358(Development)S 2918(Control)S 3264(System,)S 10 R 3600(Technical)S 4027(Report,)S 4358(Carnegie-Mellon)S 3444 V 970(University,)S 1447(Department)S 1948(of)S 2061(Computer)S 2491(Science,)S 2856(Jan.)S 3044(1979.)S 3600 V 720(9.)S 970(DEC,)S 10 I 1258(Code)S 1532(Management)S 2116(System,)S 10 R 2481(Digital)S 2823(Equipment)S 3326(Corporation,)S 3898(1982.)S 4217(Document)S 4697(No. EA-)S 3720 V 970(23134-82)S 3876 V 720(10.)S 970(Lampson,)S 1437(Butler)S 1757(W.)S 1946(and)S 2160(Schmidt,)S 2589(Eric)S 2825(E.,)S 3006(``Practical)S 3491(Use)S 3717(of)S 3871(a)S 3986(Polymorphic)S 4574(Applicative)S 3996 V 970(Language,'')S 1491(in)S 10 I 1606(Proceedings)S 2142(of)S 2257(the)S 2416(10th)S 2630(Symposium)S 3121(on)S 3257(Principles)S 3704(of)S 3818(Programming)S 4415(Languages)S 10 R 4854(,)S 4915(pp.)S 4116 V 970(237-255,)S 1358(ACM,)S 1641(January)S 1981(1983.)S 4272 V 720(11.)S 970(Tichy,)S 1260(Walter)S 1563(F.,)S 1701(``A)S 1871(Data)S 2091(Model)S 2385(for)S 2534(Programming)S 3117(Support)S 3467(Environments)S 4061(and)S 4238(its)S 4366(Application,'')S 4962(in)S 4392 V 10 I 970(Automated)S 1438(Tools)S 1696(for)S 1848(Information)S 2361(System)S 2673(Design)S 2991(and)S 3176(Development)S 10 R 3702(,)S 3761(ed.)S 3914(Hans-Jochen)S 4463(Schneider)S 4896(and)S 4512 V 970(Anthony)S 1350(I.)S 1438(Wasserman,)S 1958(North-Holland)S 2576(Publishing)S 3035(Company,)S 3479(Amsterdam,)S 4000(1982.)S 4668 V 720(12.)S 970(Heckel,)S 1328(Paul,)S 1582(``A)S 1771(Technique)S 2243(for)S 2410(Isolating)S 2811(Di)S 2911 H (f)show 10 -.5 mul h (f)show 10 R 2972(erences)S 3321(Between)S 3721(Files,'')S 10 I 4058(Communications)S 4788(of)S 4918(the)S 4788 V 970(ACM)S 10 R 1181(,)S 1236(vol.)S 1419(21,)S 1574(no.)S 1729(4,)S 1834(pp.)S 1989(264-268,)S 2377(April)S 2618(1978.)S 4944 V 720(13.)S 970(Tichy,)S 1270(Walter)S 1583(F.,)S 1731(``The)S 1994(String-to-String)S 2670(Correction)S 3139(Problem)S 3520(with)S 3740(Block)S 4021(Moves,'')S 10 I 4426(ACM)S 4679(Transac-)S 5064 V 970(tions)S 1195(on)S 1325(Computer)S 1755(Systems)S 10 R 2071(,)S 2126(vol.)S 2309(2,)S 2414(no.)S 2569(4,)S 2674(pp.)S 2829(309-321,)S 3217(Nov.)S 3444(1984.)S 7950 V 0(-)S 7950 V EP %%Trailer %%DocumentFonts: Courier Times-Roman Times-Bold Times-Italic Symbol Troff %%Pages: 20