update from main archive 961105
[glibc/history.git] / config.sub
blob4b955130417a3c8983ba348f04c2d38097549725
1 #! /bin/sh
2 # Configuration validation subroutine script, version 1.1.
3 # Copyright (C) 1991, 92, 93, 94, 95, 1996 Free Software Foundation, Inc.
4 # This file is (in principle) common to ALL GNU software.
5 # The presence of a machine in this file suggests that SOME GNU software
6 # can handle that machine. It does not imply ALL GNU software can.
8 # This file is free software; you can redistribute it and/or modify
9 # it under the terms of the GNU General Public License as published by
10 # the Free Software Foundation; either version 2 of the License, or
11 # (at your option) any later version.
13 # This program is distributed in the hope that it will be useful,
14 # but WITHOUT ANY WARRANTY; without even the implied warranty of
15 # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16 # GNU General Public License for more details.
18 # You should have received a copy of the GNU General Public License
19 # along with this program; if not, write to the Free Software
20 # Foundation, Inc., 59 Temple Place - Suite 330,
21 # Boston, MA 02111-1307, USA.
23 # As a special exception to the GNU General Public License, if you
24 # distribute this file as part of a program that contains a
25 # configuration script generated by Autoconf, you may include it under
26 # the same distribution terms that you use for the rest of that program.
28 # Configuration subroutine to validate and canonicalize a configuration type.
29 # Supply the specified configuration type as an argument.
30 # If it is invalid, we print an error message on stderr and exit with code 1.
31 # Otherwise, we print the canonical config type on stdout and succeed.
33 # This file is supposed to be the same for all GNU packages
34 # and recognize all the CPU types, system types and aliases
35 # that are meaningful with *any* GNU software.
36 # Each package is responsible for reporting which valid configurations
37 # it does not support. The user should be able to distinguish
38 # a failure to support a valid configuration from a meaningless
39 # configuration.
41 # The goal of this file is to map all the various variations of a given
42 # machine specification into a single specification in the form:
43 # CPU_TYPE-MANUFACTURER-OPERATING_SYSTEM
44 # or in some cases, the newer four-part form:
45 # CPU_TYPE-MANUFACTURER-KERNEL-OPERATING_SYSTEM
46 # It is wrong to echo any other type of specification.
48 if [ x$1 = x ]
49 then
50 echo Configuration name missing. 1>&2
51 echo "Usage: $0 CPU-MFR-OPSYS" 1>&2
52 echo "or $0 ALIAS" 1>&2
53 echo where ALIAS is a recognized configuration type. 1>&2
54 exit 1
57 # First pass through any local machine types.
58 case $1 in
59 *local*)
60 echo $1
61 exit 0
65 esac
67 # Separate what the user gave into CPU-COMPANY and OS or KERNEL-OS (if any).
68 # Here we must recognize all the valid KERNEL-OS combinations.
69 maybe_os=`echo $1 | sed 's/^\(.*\)-\([^-]*-[^-]*\)$/\2/'`
70 case $maybe_os in
71 linux-gnu*)
72 os=-$maybe_os
73 basic_machine=`echo $1 | sed 's/^\(.*\)-\([^-]*-[^-]*\)$/\1/'`
76 basic_machine=`echo $1 | sed 's/-[^-]*$//'`
77 if [ $basic_machine != $1 ]
78 then os=`echo $1 | sed 's/.*-/-/'`
79 else os=; fi
81 esac
83 ### Let's recognize common machines as not being operating systems so
84 ### that things like config.sub decstation-3100 work. We also
85 ### recognize some manufacturers as not being operating systems, so we
86 ### can provide default operating systems below.
87 case $os in
88 -sun*os*)
89 # Prevent following clause from handling this invalid input.
91 -dec* | -mips* | -sequent* | -encore* | -pc532* | -sgi* | -sony* | \
92 -att* | -7300* | -3300* | -delta* | -motorola* | -sun[234]* | \
93 -unicom* | -ibm* | -next | -hp | -isi* | -apollo | -altos* | \
94 -convergent* | -ncr* | -news | -32* | -3600* | -3100* | -hitachi* |\
95 -c[123]* | -convex* | -sun | -crds | -omron* | -dg | -ultra | -tti* | \
96 -harris | -dolphin | -highlevel | -gould | -cbm | -ns | -masscomp | \
97 -apple)
98 os=
99 basic_machine=$1
101 -hiux*)
102 os=-hiuxwe2
104 -sco5)
105 os=sco3.2v5
106 basic_machine=`echo $1 | sed -e 's/86-.*/86-pc/'`
108 -sco4)
109 os=-sco3.2v4
110 basic_machine=`echo $1 | sed -e 's/86-.*/86-pc/'`
112 -sco3.2.[4-9]*)
113 os=`echo $os | sed -e 's/sco3.2./sco3.2v/'`
114 basic_machine=`echo $1 | sed -e 's/86-.*/86-pc/'`
116 -sco3.2v[4-9]*)
117 # Don't forget version if it is 3.2v4 or newer.
118 basic_machine=`echo $1 | sed -e 's/86-.*/86-pc/'`
120 -sco*)
121 os=-sco3.2v2
122 basic_machine=`echo $1 | sed -e 's/86-.*/86-pc/'`
124 -isc)
125 os=-isc2.2
126 basic_machine=`echo $1 | sed -e 's/86-.*/86-pc/'`
128 -clix*)
129 basic_machine=clipper-intergraph
131 -isc*)
132 basic_machine=`echo $1 | sed -e 's/86-.*/86-pc/'`
134 -lynx*)
135 os=-lynxos
137 -ptx*)
138 basic_machine=`echo $1 | sed -e 's/86-.*/86-sequent/'`
140 -windowsnt*)
141 os=`echo $os | sed -e 's/windowsnt/winnt/'`
143 -psos*)
144 os=-psos
146 esac
148 # Decode aliases for certain CPU-COMPANY combinations.
149 case $basic_machine in
150 # Recognize the basic CPU types without company name.
151 # Some are omitted here because they have special meanings below.
152 tahoe | i860 | m68k | m68000 | m88k | ns32k | arm \
153 | arme[lb] | pyramid \
154 | tron | a29k | 580 | i960 | h8300 | hppa1.0 | hppa1.1 \
155 | alpha | we32k | ns16k | clipper | i370 | sh \
156 | powerpc | powerpcle | 1750a | dsp16xx | mips64 | mipsel \
157 | pdp11 | mips64el | mips64orion | mips64orionel \
158 | sparc | sparclet | sparclite | sparc64)
159 basic_machine=$basic_machine-unknown
161 # We use `pc' rather than `unknown'
162 # because (1) that's what they normally are, and
163 # (2) the word "unknown" tends to confuse beginning users.
164 i[3456]86)
165 basic_machine=$basic_machine-pc
167 # Object if more than one company name word.
168 *-*-*)
169 echo Invalid configuration \`$1\': machine \`$basic_machine\' not recognized 1>&2
170 exit 1
172 # Recognize the basic CPU types with company name.
173 vax-* | tahoe-* | i[3456]86-* | i860-* | m68k-* | m68000-* | m88k-* \
174 | sparc-* | ns32k-* | fx80-* | arm-* | c[123]* \
175 | mips-* | pyramid-* | tron-* | a29k-* | romp-* | rs6000-* | power-* \
176 | none-* | 580-* | cray2-* | h8300-* | i960-* | xmp-* | ymp-* \
177 | hppa1.0-* | hppa1.1-* | alpha-* | we32k-* | cydra-* | ns16k-* \
178 | pn-* | np1-* | xps100-* | clipper-* | orion-* | sparclite-* \
179 | pdp11-* | sh-* | powerpc-* | powerpcle-* | sparc64-* | mips64-* | mipsel-* \
180 | mips64el-* | mips64orion-* | mips64orionel-*)
182 # Recognize the various machine names and aliases which stand
183 # for a CPU type and a company and sometimes even an OS.
184 3b1 | 7300 | 7300-att | att-7300 | pc7300 | safari | unixpc)
185 basic_machine=m68000-att
187 3b*)
188 basic_machine=we32k-att
190 alliant | fx80)
191 basic_machine=fx80-alliant
193 altos | altos3068)
194 basic_machine=m68k-altos
196 am29k)
197 basic_machine=a29k-none
198 os=-bsd
200 amdahl)
201 basic_machine=580-amdahl
202 os=-sysv
204 amiga | amiga-*)
205 basic_machine=m68k-cbm
207 amigados)
208 basic_machine=m68k-cbm
209 os=-amigados
211 amigaunix | amix)
212 basic_machine=m68k-cbm
213 os=-sysv4
215 apollo68)
216 basic_machine=m68k-apollo
217 os=-sysv
219 aux)
220 basic_machine=m68k-apple
221 os=-aux
223 balance)
224 basic_machine=ns32k-sequent
225 os=-dynix
227 convex-c1)
228 basic_machine=c1-convex
229 os=-bsd
231 convex-c2)
232 basic_machine=c2-convex
233 os=-bsd
235 convex-c32)
236 basic_machine=c32-convex
237 os=-bsd
239 convex-c34)
240 basic_machine=c34-convex
241 os=-bsd
243 convex-c38)
244 basic_machine=c38-convex
245 os=-bsd
247 cray | ymp)
248 basic_machine=ymp-cray
249 os=-unicos
251 cray2)
252 basic_machine=cray2-cray
253 os=-unicos
255 [ctj]90-cray)
256 basic_machine=c90-cray
257 os=-unicos
259 crds | unos)
260 basic_machine=m68k-crds
262 da30 | da30-*)
263 basic_machine=m68k-da30
265 decstation | decstation-3100 | pmax | pmax-* | pmin | dec3100 | decstatn)
266 basic_machine=mips-dec
268 delta | 3300 | motorola-3300 | motorola-delta \
269 | 3300-motorola | delta-motorola)
270 basic_machine=m68k-motorola
272 delta88)
273 basic_machine=m88k-motorola
274 os=-sysv3
276 dpx20 | dpx20-*)
277 basic_machine=rs6000-bull
278 os=-bosx
280 dpx2* | dpx2*-bull)
281 basic_machine=m68k-bull
282 os=-sysv3
284 ebmon29k)
285 basic_machine=a29k-amd
286 os=-ebmon
288 elxsi)
289 basic_machine=elxsi-elxsi
290 os=-bsd
292 encore | umax | mmax)
293 basic_machine=ns32k-encore
295 fx2800)
296 basic_machine=i860-alliant
298 genix)
299 basic_machine=ns32k-ns
301 gmicro)
302 basic_machine=tron-gmicro
303 os=-sysv
305 h3050r* | hiux*)
306 basic_machine=hppa1.1-hitachi
307 os=-hiuxwe2
309 h8300hms)
310 basic_machine=h8300-hitachi
311 os=-hms
313 harris)
314 basic_machine=m88k-harris
315 os=-sysv3
317 hp300-*)
318 basic_machine=m68k-hp
320 hp300bsd)
321 basic_machine=m68k-hp
322 os=-bsd
324 hp300hpux)
325 basic_machine=m68k-hp
326 os=-hpux
328 hp9k2[0-9][0-9] | hp9k31[0-9])
329 basic_machine=m68000-hp
331 hp9k3[2-9][0-9])
332 basic_machine=m68k-hp
334 hp9k7[0-9][0-9] | hp7[0-9][0-9] | hp9k8[0-9]7 | hp8[0-9]7)
335 basic_machine=hppa1.1-hp
337 hp9k8[0-9][0-9] | hp8[0-9][0-9])
338 basic_machine=hppa1.0-hp
340 hppa-next)
341 os=-nextstep3
343 i370-ibm* | ibm*)
344 basic_machine=i370-ibm
345 os=-mvs
347 # I'm not sure what "Sysv32" means. Should this be sysv3.2?
348 i[3456]86v32)
349 basic_machine=`echo $1 | sed -e 's/86.*/86-pc/'`
350 os=-sysv32
352 i[3456]86v4*)
353 basic_machine=`echo $1 | sed -e 's/86.*/86-pc/'`
354 os=-sysv4
356 i[3456]86v)
357 basic_machine=`echo $1 | sed -e 's/86.*/86-pc/'`
358 os=-sysv
360 i[3456]86sol2)
361 basic_machine=`echo $1 | sed -e 's/86.*/86-pc/'`
362 os=-solaris2
364 iris | iris4d)
365 basic_machine=mips-sgi
366 case $os in
367 -irix*)
370 os=-irix4
372 esac
374 isi68 | isi)
375 basic_machine=m68k-isi
376 os=-sysv
378 m88k-omron*)
379 basic_machine=m88k-omron
381 magnum | m3230)
382 basic_machine=mips-mips
383 os=-sysv
385 merlin)
386 basic_machine=ns32k-utek
387 os=-sysv
389 miniframe)
390 basic_machine=m68000-convergent
392 mips3*-*)
393 basic_machine=`echo $basic_machine | sed -e 's/mips3/mips64/'`
395 mips3*)
396 basic_machine=`echo $basic_machine | sed -e 's/mips3/mips64/'`-unknown
398 ncr3000)
399 basic_machine=i486-ncr
400 os=-sysv4
402 news | news700 | news800 | news900)
403 basic_machine=m68k-sony
404 os=-newsos
406 news1000)
407 basic_machine=m68030-sony
408 os=-newsos
410 news-3600 | risc-news)
411 basic_machine=mips-sony
412 os=-newsos
414 next | m*-next )
415 basic_machine=m68k-next
416 case $os in
417 -nextstep* )
419 -ns2*)
420 os=-nextstep2
423 os=-nextstep3
425 esac
427 nh3000)
428 basic_machine=m68k-harris
429 os=-cxux
431 nh[45]000)
432 basic_machine=m88k-harris
433 os=-cxux
435 nindy960)
436 basic_machine=i960-intel
437 os=-nindy
439 np1)
440 basic_machine=np1-gould
442 pa-hitachi)
443 basic_machine=hppa1.1-hitachi
444 os=-hiuxwe2
446 paragon)
447 basic_machine=i860-intel
448 os=-osf
450 pbd)
451 basic_machine=sparc-tti
453 pbb)
454 basic_machine=m68k-tti
456 pc532 | pc532-*)
457 basic_machine=ns32k-pc532
459 pentium | p5)
460 basic_machine=i586-intel
462 pentiumpro | p6)
463 basic_machine=i686-intel
465 pentium-* | p5-*)
466 basic_machine=i586-`echo $basic_machine | sed 's/^[^-]*-//'`
468 pentiumpro-* | p6-*)
469 basic_machine=i686-`echo $basic_machine | sed 's/^[^-]*-//'`
472 # We don't have specific support for AMD's K5 yet, so just call it a Pentium
473 basic_machine=i586-amd
475 nexen)
476 # We don't have specific support for Nexgen yet, so just call it a Pentium
477 basic_machine=i586-nexgen
480 basic_machine=pn-gould
482 power) basic_machine=rs6000-ibm
484 ppc) basic_machine=powerpc-unknown
486 ppc-*) basic_machine=powerpc-`echo $basic_machine | sed 's/^[^-]*-//'`
488 ppcle | powerpclittle | ppc-le | powerpc-little)
489 basic_machine=powerpcle-unknown
491 ppcle-* | powerpclittle-*)
492 basic_machine=powerpcle-`echo $basic_machine | sed 's/^[^-]*-//'`
494 ps2)
495 basic_machine=i386-ibm
497 rm[46]00)
498 basic_machine=mips-siemens
500 rtpc | rtpc-*)
501 basic_machine=romp-ibm
503 sequent)
504 basic_machine=i386-sequent
507 basic_machine=sh-hitachi
508 os=-hms
510 sps7)
511 basic_machine=m68k-bull
512 os=-sysv2
514 spur)
515 basic_machine=spur-unknown
517 sun2)
518 basic_machine=m68000-sun
520 sun2os3)
521 basic_machine=m68000-sun
522 os=-sunos3
524 sun2os4)
525 basic_machine=m68000-sun
526 os=-sunos4
528 sun3os3)
529 basic_machine=m68k-sun
530 os=-sunos3
532 sun3os4)
533 basic_machine=m68k-sun
534 os=-sunos4
536 sun4os3)
537 basic_machine=sparc-sun
538 os=-sunos3
540 sun4os4)
541 basic_machine=sparc-sun
542 os=-sunos4
544 sun4sol2)
545 basic_machine=sparc-sun
546 os=-solaris2
548 sun3 | sun3-*)
549 basic_machine=m68k-sun
551 sun4)
552 basic_machine=sparc-sun
554 sun386 | sun386i | roadrunner)
555 basic_machine=i386-sun
557 symmetry)
558 basic_machine=i386-sequent
559 os=-dynix
561 tower | tower-32)
562 basic_machine=m68k-ncr
564 udi29k)
565 basic_machine=a29k-amd
566 os=-udi
568 ultra3)
569 basic_machine=a29k-nyu
570 os=-sym1
572 vaxv)
573 basic_machine=vax-dec
574 os=-sysv
576 vms)
577 basic_machine=vax-dec
578 os=-vms
580 vxworks960)
581 basic_machine=i960-wrs
582 os=-vxworks
584 vxworks68)
585 basic_machine=m68k-wrs
586 os=-vxworks
588 vxworks29k)
589 basic_machine=a29k-wrs
590 os=-vxworks
592 xmp)
593 basic_machine=xmp-cray
594 os=-unicos
596 xps | xps100)
597 basic_machine=xps100-honeywell
599 none)
600 basic_machine=none-none
601 os=-none
604 # Here we handle the default manufacturer of certain CPU types. It is in
605 # some cases the only manufacturer, in others, it is the most popular.
606 mips)
607 basic_machine=mips-mips
609 romp)
610 basic_machine=romp-ibm
612 rs6000)
613 basic_machine=rs6000-ibm
615 vax)
616 basic_machine=vax-dec
618 pdp11)
619 basic_machine=pdp11-dec
621 we32k)
622 basic_machine=we32k-att
624 sparc)
625 basic_machine=sparc-sun
627 cydra)
628 basic_machine=cydra-cydrome
630 orion)
631 basic_machine=orion-highlevel
633 orion105)
634 basic_machine=clipper-highlevel
637 echo Invalid configuration \`$1\': machine \`$basic_machine\' not recognized 1>&2
638 exit 1
640 esac
642 # Here we canonicalize certain aliases for manufacturers.
643 case $basic_machine in
644 *-digital*)
645 basic_machine=`echo $basic_machine | sed 's/digital.*/dec/'`
647 *-commodore*)
648 basic_machine=`echo $basic_machine | sed 's/commodore.*/cbm/'`
652 esac
654 # Decode manufacturer-specific aliases for certain operating systems.
656 if [ x"$os" != x"" ]
657 then
658 case $os in
659 # First match some system type aliases
660 # that might get confused with valid system types.
661 # -solaris* is a basic system type, with this one exception.
662 -solaris1 | -solaris1.*)
663 os=`echo $os | sed -e 's|solaris1|sunos4|'`
665 -solaris)
666 os=-solaris2
668 -unixware* | svr4*)
669 os=-sysv4
671 -gnu/linux*)
672 os=`echo $os | sed -e 's|gnu/linux|linux-gnu|'`
674 # First accept the basic system types.
675 # The portable systems comes first.
676 # Each alternative MUST END IN A *, to match a version number.
677 # -sysv* is not here because it comes later, after sysvr4.
678 -gnu* | -bsd* | -mach* | -minix* | -genix* | -ultrix* | -irix* \
679 | -*vms* | -sco* | -esix* | -isc* | -aix* | -sunos | -sunos[34]*\
680 | -hpux* | -unos* | -osf* | -luna* | -dgux* | -solaris* | -sym* \
681 | -amigados* | -msdos* | -newsos* | -unicos* | -aof* | -aos* \
682 | -nindy* | -vxsim* | -vxworks* | -ebmon* | -hms* | -mvs* \
683 | -clix* | -riscos* | -uniplus* | -iris* | -rtu* | -xenix* \
684 | -hiux* | -386bsd* | -netbsd* | -freebsd* | -riscix* \
685 | -lynxos* | -bosx* | -nextstep* | -cxux* | -aout* | -elf* \
686 | -ptx* | -coff* | -ecoff* | -winnt* | -domain* | -vsta* \
687 | -udi* | -eabi* | -lites* | -ieee* | -go32* | -aux* \
688 | -cygwin32* | -pe* | -psos* | -moss* | -proelf* | -rtems* \
689 | -linux-gnu*)
690 # Remember, each alternative MUST END IN *, to match a version number.
692 -linux*)
693 os=`echo $os | sed -e 's|linux|linux-gnu|'`
695 -sunos5*)
696 os=`echo $os | sed -e 's|sunos5|solaris2|'`
698 -sunos6*)
699 os=`echo $os | sed -e 's|sunos6|solaris3|'`
701 -osfrose*)
702 os=-osfrose
704 -osf*)
705 os=-osf
707 -utek*)
708 os=-bsd
710 -dynix*)
711 os=-bsd
713 -acis*)
714 os=-aos
716 -ctix* | -uts*)
717 os=-sysv
719 -ns2 )
720 os=-nextstep2
722 # Preserve the version number of sinix5.
723 -sinix5.*)
724 os=`echo $os | sed -e 's|sinix|sysv|'`
726 -sinix*)
727 os=-sysv4
729 -triton*)
730 os=-sysv3
732 -oss*)
733 os=-sysv3
735 -svr4)
736 os=-sysv4
738 -svr3)
739 os=-sysv3
741 -sysvr4)
742 os=-sysv4
744 # This must come after -sysvr4.
745 -sysv*)
747 -xenix)
748 os=-xenix
750 -none)
753 # Get rid of the `-' at the beginning of $os.
754 os=`echo $os | sed 's/[^-]*-//'`
755 echo Invalid configuration \`$1\': system \`$os\' not recognized 1>&2
756 exit 1
758 esac
759 else
761 # Here we handle the default operating systems that come with various machines.
762 # The value should be what the vendor currently ships out the door with their
763 # machine or put another way, the most popular os provided with the machine.
765 # Note that if you're going to try to match "-MANUFACTURER" here (say,
766 # "-sun"), then you have to tell the case statement up towards the top
767 # that MANUFACTURER isn't an operating system. Otherwise, code above
768 # will signal an error saying that MANUFACTURER isn't an operating
769 # system, and we'll never get to this point.
771 case $basic_machine in
772 *-acorn)
773 os=-riscix1.2
775 arm*-semi)
776 os=-aout
778 pdp11-*)
779 os=-none
781 *-dec | vax-*)
782 os=-ultrix4.2
784 m68*-apollo)
785 os=-domain
787 i386-sun)
788 os=-sunos4.0.2
790 m68000-sun)
791 os=-sunos3
792 # This also exists in the configure program, but was not the
793 # default.
794 # os=-sunos4
796 *-tti) # must be before sparc entry or we get the wrong os.
797 os=-sysv3
799 sparc-* | *-sun)
800 os=-sunos4.1.1
802 *-ibm)
803 os=-aix
805 *-hp)
806 os=-hpux
808 *-hitachi)
809 os=-hiux
811 i860-* | *-att | *-ncr | *-altos | *-motorola | *-convergent)
812 os=-sysv
814 *-cbm)
815 os=-amigados
817 *-dg)
818 os=-dgux
820 *-dolphin)
821 os=-sysv3
823 m68k-ccur)
824 os=-rtu
826 m88k-omron*)
827 os=-luna
829 *-next )
830 os=-nextstep
832 *-sequent)
833 os=-ptx
835 *-crds)
836 os=-unos
838 *-ns)
839 os=-genix
841 i370-*)
842 os=-mvs
844 *-next)
845 os=-nextstep3
847 *-gould)
848 os=-sysv
850 *-highlevel)
851 os=-bsd
853 *-encore)
854 os=-bsd
856 *-sgi)
857 os=-irix
859 *-siemens)
860 os=-sysv4
862 *-masscomp)
863 os=-rtu
866 os=-none
868 esac
871 # Here we handle the case where we know the os, and the CPU type, but not the
872 # manufacturer. We pick the logical manufacturer.
873 vendor=unknown
874 case $basic_machine in
875 *-unknown)
876 case $os in
877 -riscix*)
878 vendor=acorn
880 -sunos*)
881 vendor=sun
883 -lynxos*)
884 vendor=lynx
886 -aix*)
887 vendor=ibm
889 -hpux*)
890 vendor=hp
892 -hiux*)
893 vendor=hitachi
895 -unos*)
896 vendor=crds
898 -dgux*)
899 vendor=dg
901 -luna*)
902 vendor=omron
904 -genix*)
905 vendor=ns
907 -mvs*)
908 vendor=ibm
910 -ptx*)
911 vendor=sequent
913 -vxsim* | -vxworks*)
914 vendor=wrs
916 -aux*)
917 vendor=apple
919 esac
920 basic_machine=`echo $basic_machine | sed "s/unknown/$vendor/"`
922 esac
924 echo $basic_machine$os