time sources : Java Glossary

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time sources
In our technological world there are many ways you can get the current time and date. Here is an eclectic list of time sources:
  1. From GPS satellites. GPS (Global Positioning System) provides a most excellent time source since it naturally compensates for propagation delay and is immune to network congestion and weather.
  2. setclock icon  SetClock is a Java Applet you can run on your PC (Personal Computer). It will get the accurate time from an atomic clock on the web provided by pool.ntp.org.
  3. From an atomic clock timeserver on the web using NTP NTP (Network Time Protocol). Timeservers come is various grades of accuracy. You are not supposed to pester the very accurate ones. They are for the secondary servers.
    NTP Time Servers
    Where Server IP (Internet Protocol) Can Use
    Without
    Notification
    AM ntp.adc.am 91.103.24.10
    AO ao.pool.ntp.org 196.216.249.2
    AR ar.pool.ntp.org 200.11.116.1
    AR tick.nap.com.ar 200.10.140.1
    AR time.sinectis.com.ar 216.244.192.3
    AR tock.nap.com.ar 200.10.140.1
    AT at.pool.ntp.org 213.129.242.94
    AU au.pool.ntp.org 203.23.237.200
    AU ntp.au.zoidial.com 202.53.7.202
    AU ntp.mazzanet.id.au 203.206.205.83
    AU ntp.sjkwi.com.au 203.206.185.142
    AU ntp.tourism.wa.gov.au 203.161.12.165
    AU ntp1.tpg.com.au 203.12.160.2
    AU ntp2.tpg.com.au 203.26.24.6
    Africa africa.pool.ntp.org 41.204.120.137
    Asia asia.pool.ntp.org 120.88.46.10
    BA ba.pool.ntp.org 195.222.33.219
    BD bd.pool.ntp.org 202.168.228.131
    BE be.pool.ntp.org 85.158.108.151
    BE ntp1.belbone.be 195.13.23.5
    BE ntp2.belbone.be 195.13.1.153
    BG bg.pool.ntp.org 77.78.146.237
    BR a.ntp.br 200.160.0.8
    BR b.ntp.br 200.189.40.8
    BR br.pool.ntp.org 200.192.232.8
    BR c.ntp.br 200.192.232.8
    BR ntp.cais.rnp.br 200.144.121.33
    BR ntp.hiway.com.br 200.220.152.62
    BR ntp.pads.ufrj.br 146.164.48.1
    BR ntp.pop-pr.rnp.br 200.19.74.21
    BR ntp1.pucpr.br 200.192.112.8
    BS bs.pool.ntp.org 208.87.33.150
    BY by.pool.ntp.org 93.84.115.2
    CA ca.pool.ntp.org 216.46.5.9
    CA ntp.cpsc.ucalgary.ca 136.159.2.9
    CA ntp1.cmc.ec.gc.ca 199.212.17.34
    CA ntp1.linuxhosted.ca 72.20.40.62
    CA ntp2.cmc.ec.gc.ca 199.212.17.35
    CA ntp2.linuxhosted.ca 72.20.40.62
    CA ntp3.linuxhosted.ca 72.20.40.62
    CA time.chu.nrc.ca 209.87.233.53
    CA time.nrc.ca 132.246.168.164
    CA SK Regina timelord.uregina.ca 142.3.100.15
    CH b.ntp.madduck.net 130.60.75.52
    CH c.ntp.madduck.net 130.60.75.53
    CH ch.pool.ntp.org 217.147.208.1
    CH clock.tix.ch 195.141.190.190
    CH ntp.favey.ch 195.34.89.227
    CH ntp.metas.ch 162.23.41.34
    CH ntp11.metas.ch 162.23.41.55
    CH ntp12.metas.ch 162.23.41.56
    CH tack.meteonews.ch 62.2.104.140
    CH tick.meteonews.ch 91.195.238.4
    CL cl.pool.ntp.org 146.83.183.179
    CN cn.pool.ntp.org 61.153.197.226
    CN hshh.org 218.75.4.130
    CN t1.hshh.org 218.75.4.130
    CN t3.hshh.org 114.80.81.13
    CR cr.pool.ntp.org 190.106.66.11
    CZ cz.pool.ntp.org 81.0.235.220
    CZ ntp.cgi.cz 81.0.239.181
    CZ ntp.karpo.cz 81.0.237.209
    CZ ntp.ujf.cas.cz 147.231.100.5
    CZ ntp1.contactel.cz 212.65.193.138
    CZ ntp2.contactel.cz 212.65.193.134
    DE a.ntp.madduck.net 213.203.238.86
    DE de.pool.ntp.org 131.188.3.222
    DE gwyn.kn-bremen.de 78.46.108.116
    DE hera.limescope.net 188.40.128.210
    DE ntp.dianacht.de 77.37.6.59
    DE ntp.netzwerkteufel.net 85.214.116.15
    DE ntp.rueckgr.at 85.31.187.67
    DE ntp1.madavi.de 62.8.239.62
    DE ntp1.theremailer.net 85.10.240.253
    DE ntp2.hauke-lampe.de 213.9.73.106
    DE ntp2.madavi.de 62.8.242.2
    DE ntp3.madavi.de 62.8.239.2
    DE stratum2-3.NTP.TechFak.Uni-Bielefeld.de 129.70.132.32
    DE stratum2-3.NTP.TechFak.Uni-Bielefeld.de 129.70.132.32
    DE stratum2-4.NTP.TechFak.Uni-Bielefeld.de 129.70.132.33
    DE time.edv-froehlich.de 94.125.65.13
    DE time2.one4vision.de 212.82.32.26
    DE zeus.limescope.net 188.40.85.143
    DK dk.pool.ntp.org 62.243.224.43
    DK ntp.dvconsulting.dk 195.234.155.123
    DK ntp.gal.dk 195.234.155.124
    EE (Enterprise Edition) ee.pool.ntp.org 193.40.133.142
    ES es.pool.ntp.org 77.226.252.14
    ES hora.oxixares.com 93.189.33.204
    Europe europe.pool.ntp.org 85.214.116.15
    FI fi.pool.ntp.org 194.100.2.198
    FI ntp.lekksi.com 81.22.251.67
    FI tick.keso.fi 82.197.0.130
    FI tock.keso.fi 82.197.0.130
    FR fr.pool.ntp.org 94.23.196.225
    FR ntp.crifo.org 88.191.101.3
    FR ntp.demongeot.biz 93.184.32.4
    FR ntp.home-dn.net 88.191.11.98
    FR ntp.obspm.fr 145.238.203.10
    FR ntp2.linocomm.net 72.167.55.133
    FR Lyon ntp.univ-lyon1.fr 134.214.100.60
    GR gr.pool.ntp.org 192.108.114.23
    GR ntp.databank.com.gr 193.164.227.145
    GR ntp.mfa.gr 195.167.30.249
    HK hk.pool.ntp.org 202.131.74.125
    HK ntp.cuhk.edu.hk 137.189.11.181
    HR hr.pool.ntp.org 161.53.131.81
    HR os.ntp.carnet.hr 161.53.30.100
    HR ri.ntp.carnet.hr 161.53.40.3
    HR st.ntp.carnet.hr 161.53.30.50
    HR zg1.ntp.carnet.hr 161.53.160.4
    HR zg2.ntp.carnet.hr 161.53.160.5
    HU hu.pool.ntp.org 193.225.14.163
    HU ntp.mandrivalinux.hu 213.157.100.100
    HU time.kfki.hu 148.6.0.1
    ID id.pool.ntp.org 203.160.128.3
    IE ie.pool.ntp.org 86.43.125.255
    IE ntp.maths.tcd.ie 134.226.81.3
    IE Dublin salmon.maths.tcd.ie 134.226.81.11
    IN in.pool.ntp.org 120.88.46.10
    IR ir.pool.ntp.org 92.61.176.135
    IT it.pool.ntp.org 212.45.144.59
    IT ntp.prato.linux.it 62.48.35.100
    IT quassia.associazione-tp.it 212.45.144.11
    JP jp.pool.ntp.org 202.234.64.222
    KR cse.inha.ac.kr 165.246.43.176
    KR kr.pool.ntp.org 211.233.40.78
    KR rafi.inha.ac.kr 165.246.43.195
    LK lk.pool.ntp.org 122.255.43.151
    LT lt.pool.ntp.org 212.122.84.84
    LU lu.pool.ntp.org 80.92.86.18
    LV lv.pool.ntp.org 80.81.32.231
    MD md.pool.ntp.org 95.65.29.212
    MD ntp.fedoramd.org 95.65.63.19
    MD ntp2.idsi.md 193.226.65.2
    MG mg.pool.ntp.org 196.192.32.7
    MK mk.pool.ntp.org 95.180.132.5
    MX mx.pool.ntp.org 201.155.229.129
    MY my.pool.ntp.org 219.95.243.198
    NC nc.pool.ntp.org 202.171.65.25
    NL nl.pool.ntp.org 213.206.97.167
    NL ntp.edge.tillo.ch 85.17.207.62
    NL ntp.grafix.nl 217.67.231.25
    NL ntp.minian.org 83.96.227.85
    NL ntp.wsrs.net 85.17.71.101
    NL ntp2.remco.org 213.10.47.241
    NL serv01.richs.nl 195.241.158.50
    NO fartein.ifi.uio.no 129.240.64.3
    NO no.pool.ntp.org 139.117.2.20
    NO ntp-public.uit.no 129.242.4.241
    NZ ntp.iprolink.co.nz 203.152.100.32
    NZ ntp.massey.ac.nz 130.123.2.99
    NZ ntp.public.otago.ac.nz 139.80.64.114
    NZ nz.pool.ntp.org 218.185.224.8
    NZ tk1.ihug.co.nz 203.109.252.7
    NZ tk2.ihug.co.nz 203.109.252.32
    NZ tk3.ihug.co.nz 203.109.252.5
    North America 0.north-america.pool.ntp.org 70.86.250.6
    North America 1.north-america.pool.ntp.org 65.255.217.202
    North America 2.north-america.pool.ntp.org 128.61.40.113
    North America 3.north-america.pool.ntp.org 207.171.30.106
    OM om.pool.ntp.org 85.154.240.78
    Oceania oceania.pool.ntp.org 202.83.64.2
    PA ntp1.linocomm.net 200.35.147.189
    PA pa.pool.ntp.org 64.209.30.130
    PH ph.pool.ntp.org 202.92.128.201
    PK pk.pool.ntp.org 203.82.48.3
    PL ntp2.net.icm.edu.pl 212.87.0.71
    PL ntp2.radioalfa.pl 89.171.11.30
    PL pl.pool.ntp.org 83.16.194.42
    PT ntp04.oal.ul.pt 194.117.9.136
    PT pt.pool.ntp.org 194.117.9.136
    RO ro.pool.ntp.org 93.190.144.26
    RS rs.pool.ntp.org 147.91.8.77
    RU ntp.letinet.ru 95.140.94.2
    RU ntp1.kangran.su 93.185.187.89
    RU ntp2.kangran.su 94.26.135.117
    RU ntp21.imvp.ru 62.117.76.139
    RU ru.pool.ntp.org 193.41.86.177
    RU ticktock.net.ru 80.93.53.29
    SE ntp.systemtid.se 78.70.44.132
    SE se.pool.ntp.org 80.67.2.135
    SE time.flygplats.net 213.114.139.243
    SE www.millnet.se 85.8.21.133
    SG (Signal Ground) sg.pool.ntp.org 116.214.96.10
    SI (Systèm Internationale (metric)) ntp1.arnes.si 193.2.1.117
    SI ntp2.arnes.si 193.2.1.92
    SI si.pool.ntp.org 89.212.75.6
    SK sk.pool.ntp.org 92.240.244.202
    SV sv.pool.ntp.org 168.243.227.194
    South America south-america.pool.ntp.org 200.80.32.172
    South Australia ntp.adelaide.edu.au 129.127.40.3
    TH th.pool.ntp.org 158.108.2.100
    TR ntp1.sibernet.com.tr 81.213.156.223
    TR ntp1.sibernet.com.tr 81.213.156.223
    TR time.deu.edu.tr 194.27.110.130
    TR tr.pool.ntp.org 188.124.15.164
    TW tw.pool.ntp.org 140.112.126.36
    UA ntp.vc.ukrtel.net 213.179.228.16
    UA ua.pool.ntp.org 213.179.228.6
    UK extntp0.inf.ed.ac.uk 129.215.160.240
    UK ntp.cis.strath.ac.uk 130.159.196.118
    UK ntp.exnet.com 79.135.97.79
    UK ntp.markyate.net 84.45.170.220
    UK ntp1.uk.uu.net 158.43.128.66
    UK tick.myodn.ch 109.74.202.157
    UK uk.ntp.f-box.org 85.234.144.165
    UK uk.pool.ntp.org 194.238.48.2
    UK Manchester ntp2a.mcc.ac.uk 130.88.202.49
    UK Manchester ntp2b.mcc.ac.uk 130.88.200.4
    UK Manchester ntp2c.mcc.ac.uk 130.88.200.6
    UK Manchester ntp2d.mcc.ac.uk 130.88.212.143
    UK Scotland Glasgow ntp.cs.strath.ac.uk 130.159.196.118
    US ac-ntp0.net.cmu.edu 128.2.1.20
    US ac-ntp1.net.cmu.edu 128.2.1.21
    US ac-ntp2.net.cmu.edu 128.2.1.22
    US clock.fihn.net 72.13.92.34
    US morose.quex.org 206.222.28.90
    US ntp.myfloridacity.us 71.40.128.157
    US ntp.qays.net 66.92.45.31
    US ntp.rfnj.org 74.63.215.214
    US ntp1.chrisjohnston.org 67.23.9.147
    US ntp1.sjbcom.com 65.216.242.42
    US ntp1.stsn.net 72.254.0.254
    US ntp2.chrisjohnston.org 67.23.7.164
    US ntp3.stsn.net 72.255.0.254
    US ntp5.tamu.edu 128.194.254.9
    US ntppub.tamu.edu 128.194.254.9
    US saman-gh.co.uk 97.107.132.48
    US thecraag.com 96.238.93.48
    US time.cachenetworks.com 69.22.157.2
    US us.pool.ntp.org 216.184.20.83
    US AR sushi.lyon.edu 66.76.114.4
    US AZ decimal.lib.ci.phoenix.az.us 148.167.132.201
    US AZ dewey.lib.ci.phoenix.az.us 148.167.132.200
    US AZ ntp3.linocomm.net 72.167.54.201
    US CA clock.develooper.com 207.171.7.151
    US CA ntp.drydog.com 66.27.60.10
    US CA ntp1.sf-bay.org 192.83.249.28
    US CA ntp2.sf-bay.org 204.74.68.55
    US CA reloj.kjsl.com 216.129.110.22
    US CA reva.ziaspace.com 206.221.211.41
    US CA stratum2.sjc1.publicntp.net 69.36.249.227
    US CA time.berkeley.netdot.net 66.93.136.202
    US CO ntp1.linuxmedialabs.com 63.247.194.250
    US DE Newark louie.udel.edu 128.4.40.12
    US GA rolex.usg.edu 131.144.4.10
    US IL ntp.mya.org 99.14.237.170
    US IL stratum2.ord2.publicntp.net 208.100.0.38
    US IL Urbana-Champaign ntp-0.cso.uiuc.edu 130.126.24.53
    US IL Urbana-Champaign ntp-1.cso.uiuc.edu 130.126.24.24
    US IL Urbana-Champaign ntp-2.cso.uiuc.edu 130.126.24.44
    US KS ntp1.kansas.net 64.6.144.6
    US KS ntp2.kansas.net 199.240.130.1
    US MA timelord.w1nr.net 98.110.253.24
    US MN nss.nts.umn.edu 134.84.84.84
    US MN ntp.skoglundtech.com 173.16.80.149
    US MN ntp157.sntp.us 63.228.0.157
    US MT chronos1.umt.edu 192.73.48.1
    US MT chronos2.umt.edu 192.73.48.2
    US MT chronos3.umt.edu 192.73.48.6
    US NC clock1.unc.edu 152.2.21.1
    US NJ tick.jrc.us 208.90.144.52
    US NJ tock.jrc.us 208.90.144.53
    US NV cuckoo.nevada.edu 131.216.1.101
    US NV tick.cs.unlv.edu 131.216.22.24
    US NV Las Vegas tock.cs.unlv.edu 131.216.22.26
    US NY alice.ziaspace.com 69.31.45.60
    US NY andromeda.ziaspace.com 192.80.49.10
    US NY ntp.pbx.org 66.250.45.2
    US NY ntp0.cornell.edu 132.236.56.250
    US NY sundial.columbia.edu 128.59.59.177
    US NY New York timex.cs.columbia.edu 128.59.16.20
    US PA fuzz.psc.edu 128.182.58.100
    US PA University Park clock.psu.edu 128.118.25.3
    US TX chrono.cis.sac.accd.edu 209.184.112.197
    US TX ntp.bytestacker.com 69.164.194.127
    US TX ntp.fwwds.com 99.72.86.235
    US TX ntp.jentfoo.com 173.203.211.73
    US TX ntp.tmc.edu 128.249.1.10
    US TX ntp1.jtsage.com 72.14.177.132
    US TX ntp2.jtsage.com 72.14.179.211
    US TX sundial.cis.sac.accd.edu 209.184.112.198
    US TX tick.mattnordhoff.com 67.18.187.111
    US TX ticker.cis.sac.accd.edu 209.184.112.199
    US TX time.xenscale.com 72.14.188.195
    US VA (Volt-Amps) ntp-1.vt.edu 198.82.1.201
    US VA ntp-2.vt.edu 198.82.1.202
    US VA ntp-3.vt.edu 198.82.1.203
    US VA ntp-4.vt.edu 198.82.1.204
    US VA Blacksburg vtserf.cc.vt.edu 198.82.162.213
    US WA tick.mtnlion.com 204.13.164.164
    US WI ntp1.netwrx1.com 68.248.203.41
    US WI ntp3.netwrx1.com 68.248.203.42
    US WI ntp3.sf-bay.org 206.55.70.42
    US WI Madison ntp1.cs.wisc.edu 128.105.39.11
    US WI Madison ntp2.cs.wisc.edu 128.105.38.11
    US WI Madison ntp3.cs.wisc.edu 128.105.37.11
    UZ uz.pool.ntp.org 217.29.116.2
    VE ve.pool.ntp.org 190.202.98.221
    VN vn.pool.ntp.org 113.161.84.133
    YU yu.pool.ntp.org 212.200.82.130
    ZA za.pool.ntp.org 196.25.1.9
    worldwide pool.ntp.org 216.234.161.11
    Last revised/verified: 2010-03-15
  4. java.lang.System.currentTimeMillis () will give you the time in milliseconds since 1970 Jan 1 0:00 GMT (Greenwich Mean Time). This is your best bet for computing elapsed times. Freshly minted java.util.Date objects contain the current GMT date/time stamp as do freshly minted java.util. GregorianCalendar objects.
  5. Time.gov is a government website that will give you local time.
  6. XP/W2003/Vista/W2008/W7-32/W7-64 will consult a Microsoft web clock if you issue the command w32tm.exe /resync or right click the time display in the bottom right and select adjust date and time ⇒ Internet time. If time.windows.com time source is not reliable, (the usual case) you can configure the timeserver to a different one, perhaps from pool.ntp.org, e.g. us.pool.ntp.org, ca.pool.ntp.org… w32tm.exe will only work after the W32Time service is started in the Windows task manager.
  7. pool.ntp.org maintains a set of servers all over the world. You can find one just by prefixing your 2-letter country code e.g ch.pool.ntp.org for Switzerland or ca.pool.ntp.org for Canada or us.pool.ntp.org for the USA. The W32Time service must be running for W32tm.exe to work. You can start it from the command line with sc.exe start W32Time.
  8. atomic wall clock From the NIST (National Institute of Standards and Technology) WWVB radio signal broadcast from Fort Collins, Colorado. This is how high tech wall clocks and wrist watches maintain perfect time and know when to flip back and forth to daylight savings. They are called analog atomic clocks and digital atomic clocks, though there is nothing radioactive in them. They are merely radio-synchronised from a government atomic clock.
    radio-synched clocks for more details and information on where to buy them
  9. From a signal PBS embeds in its TV broadcasts. This is how VCRs (Videocassette Recorders) can get the time automatically.
  10. From the CBC (Canadian Broadcasting Corporation) radio time signal each day at 10 AM on the FM broadcast stations.
  11. From a signal broadcast on the AC (Alternating Current) power, put here by the utility company.
  12. From your TV Station broadcast channel guide.
atomic clock
benchmark
Calendar
clock
country codes
currency codes
Date
daylight saving time
GMT
gotchas for extensive hints on date/time processing
leap second
longitude
Microsoft File Times
mixed base
NTP
OpenType
Pentium RDTSC high resolution timer
pool.ntp.org
profiler
radio-synched clock
RDTSC: coding an RDTSC access in assembler
SetClock
SI prefixes such as pico and femto
sleep
TAI
time
Timer
timestamp
UTC
Windows Time
Windows Vista
CMP homejump to top

available on the web at:

 http://mindprod.com/jgloss/timesources.html
  

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