O skopos aytou toy keimenoy einai na dwsei katanohtous deiktes/URLs gia na sthsete grhgora thn PostgreSQL kai epishs na yperaspistei ta pleonekthmata enos Anoiktou Systhmatos Phgaioy Kwdika (Open Source Code) opws h PostgreSQL, Linux.
Ka8e susthma ypologisth ston kosmo xreiazetai mia bash dedomenwn gia na apo8hkeuei /anakta plhrofories. O kurios logos poy xrhsimopoioume ton ypologisth einai gia na apo8hkeuoyme, na anaktoume kai na epejergazomaste thn plhroforia kai na ta kanoyme ola ayta grhgora, ejoikonomwntas etsi xrono. Taytoxrona, to susthma prepei na einai aplo, ajiopisto, oikonomiko kai polu eukolo sth xrhsh toy. H Bash Dedomenwn einai SYSTHMA ZWTIKHS SHMASIAS gia ka8e etairia ston kosmo mia kai se ayth apo8hkeuontai polu shmantikes plhrofories. Ta pio dhmofilh systhmata basewn dedomenwn basizontai stis SQL prodiagrafes toy Die8nous Organismou Protupwn ISO (International Standard Organisation) oi opoies basizontai me th seira toys sto protypo ANSI SQL (Amerikaniko). Oi trexoyses prodiagrafes poy xrhsimopoiountai eyrews einai oi ISO/ANSI SQL 1992. To mellontiko protypo einai to SQL 1998/99 gnwsto kai san SQL-3 kai anaptussetai akomh. Dhmofileis baseis opws h Oracle, h Sybase kai Informix einai systhmata basismena se ayta ta protypa h prospa8oun na ta ylopoihsoyn.
Opws fainetai se ayto to keimeno, yparxoyn perissotera apo 20 diaforetika systhmata basewn dedomenwn, emporika/basismena sto internet, poy xrhsimopoiountai se olo ton kosmo kai polla perissotera 8a emfanistoun sto prosexes mellon. Xwris ena protypo opws to ANSI/ISO SQL, 8a htan polu duskolo gia ton pelath na anaptujei mia efarmogh mia mono fora kai na th trexei se ola ta systhmata basewn dedomenwn. O shmerinos pelaths 8elei na anaptujei mia efarmogh mia fora xrhsimopoiwntas ISO SQL, ODBC, JDBC kai na thn poylhsei wste na xrhsimopoieitai se ola ta diaforetika systhmata basewn dedomenwn ston kosmo.
H dhmofilesterh pagkosmiws DWREAN bash, poy ylopoiei tmhma toy ISO SQL, ANSI SQL/98, SQL/92 kai ANSI SQL/89 RDBMS einai h PostgreSQL. H PostgreSQL einai h Antikeimenostrafhs Sxesiakh SQL Bash epomenhs genias kai ta mellontika protypa ANSI SQL opws to SQL 1998 (SQL-3) kai pera 8a asxolountai olo kai perissotero me Antikeimenostrafeis Baseis kai tupoys dedomenwn Antikeimenoy (Object data types). H PostgreSQL einai to mono dwrean RDBMS ston kosmo poy yposthrizei Antikeimenostrafeis Baseis kai SQL. Ayto to keimeno 8a sas pei pws na egkatasthsete th bash kai, epishs, ola ta paketa sxetika me baseis, pws na egkatasthsete Web database, application database, grafika programmata epikoinwnias kai xeirismou (front end GUIs kai programmata interface). Sas symboyleuoyme na gracete OPWSDHPOTE tis efarmoges basewn 100 % symbates me ta protypa ISO/ANSI SQL, ODBC, JDBC, etsi wste h efarmogh sas na einai metafersimh se polles baseis opws oi PostgreSQL, Oracle, Sybase, Informix klp.
Me thn PostgreSQL, 8a exete thn ychloterh poiothta kai polla alla xarakthristika mia kai akoloy8ei to 'Anoikto Montelo Anaptyjhs Phgaioy Kwdika' (Open Source Code development). To Anoikto montelo Anaptyjhs Phgaioy Kwdika einai to mono toy opoioy mporeite na parete olon ton phgaio kwdika, kai h anaptyjh ginetai sto internet apo ejairetika megalo diktyo an8rwpinwn myalwn. H mellontikh moda problepei oti h megaluterh anaptyjh logismikou 8a ginetai sthn apokaloumenh "Yperlewforo Plhroforiwn" (Information Super-Highway) poy diatrexei olo ton kosmo. Sta xronia poy erxontai, h anaptyjh toy internet 8a einai ekrhktikh h opoia me th seira ths 8a pyrodothsei th grhgorh yio8ethsh ths PostgreSQL apo toys pelates.
Efarmozontas tis arxes ths fysikhs (kbantomhxanikh, klassikh, 8ermodynamikh), twn ma8hmatikwn kai ths statistikhs sthn poiothta toy logismikou, pairnete thn ychloterh poiothta logismikou mono se ena 'Anoikto Susthma Phgaioy Kwdika' opws h PostgreSQL anoigontas ton phgaio kwdika se ena pelwrio ari8mo an8rwpinwn myalwn diasyndedemenwn mesw ths Yperlewforoy Plhroforiwn. Oso megaluteros o ari8mos twn an8rwpwn poy ergazontai panw s' ayto, toso kaluterh 8a einai h poiothta toy logismikou. To Anoikto Montelo Phgaioy Kwdika 8a empodisei epishs thn anakalych toy troxou apo thn arxh , 8a meiwsei th diplh doyleia kai 8a einai polu oikonomiko, 8a ejoikonomei xrono sth dianomh kai akoloy8ei toys nomoys ths monternas oikonomias gia beltistopoihsh twn e8nikwn kai genikwn porwn. Otan mia ergasia logismikou exei ginei apo alloys, tote DEN xreiazetai na thn kanete eseis pali. De 8a spatalhsete ton polutimo xrono sas se kati poy exei hdh ginei kala. Ka8ws 8a mpainoyme ston 21o aiwna, 8a yparxei allagh ston tropo poy pairnoyme to logismiko gia xrhsh. Oi pelates 8a protimoun ta anoikta systhmata logismikou opws h PostgreSQL, to Linux klp.
An agorasete ektelesima programmata, de 8a parete kai ton kwdika kai ta dikaiwmata toy. O phgaios kwdikas einai anektimhto stoixeio enw ta ektelesima den exoyn kamia ajia. To na agorasete logismiko mporei na anhkei sto parel8on. Gia na agorasete kalo yliko (hardware), ajizei na jodecete xrhmata kai na parete to logismiko apo to internet. Shmantiko shmeio einai to yliko toy ypologisth to opoio kanei ton kurio ogko ths doyleias. To yliko einai to alogo poy kanei th doyleia enw to logismiko apla to odhgei. To yliko twn ypologistwn einai polu poluploko kai mono 6 apo tis 180 xwres ston kosmo mexri twra exoyn epideijei thn ikanothta sxediasmou kai kataskeyhs plaketwn/ylikou ypologistwn. O sxediasmos kai h kataskeyh chips ypologistwn einai prohgmenh texnologia. Einai mia polu sun8eth diadikasia, dapanhrh, apaitei megales ependuseis se ergostasia kai mhxanes paragwghs poy doyleuoyn me texnologia 0.18 micron. Se ena mikro chip silikonhs ekatommuria tranzistors/kyklwmata einai stena paketarismena. Etaireies opws oi AMD, Intel, Cyrix, Hitachi, IBM kai alles jodecan shmantiko ari8mo apo an8rwpoxronia gia na ginoyn kurioi ychlwn texnologiwn opws h mikrohlektronikh (Micro-electronics) kai h nanohlektronikh (Nano-electronics). Micro shmainei (ena-ekatommyriosto toy metroy 10^-6), Nano shmainei (ena-disekatommyriosto toy metroy 10^-9). H trexoysa texnologia xrhsimopoiei mikrohlektronikh gurw sta 0.35 micron xrhsimopoiwntas agwgous aloyminioy, kai mege8h twn 0.25 micron xrhsimopoiwntas agwgous hlektroniwn apo xalko. Sto kontino mas mellon 8a xrhsimopoih8ei texnologia twn 0.10 micron me xalko kai nanohlektronikh gia na ftiajoyn tsipakia ypologisth. Oi agwgoi aloyminioy 8a antikatasta8oun apo xalko sta chips twn ypologistwn, ka8ws o xalkos einai kaluteros agwgos twn hlektroniwn. Sth fwtoli8ografia, 8a xrhsimopoih8oun texnikes yperiwdoys aktinobolias, aktines X h desmhs hlektroniwn gia xarajh kyklwmatwn me mellontika mege8h mikrotera twn 0.15 micron.
Se 20 xronia apo twra, ta tsip silikonhs 8a antikatasta8oun apo moriakous ypologistes kai biotsips poy 8a einai disekatommuria fores grhgorotera apo ta tsip silikonhs. Ta moria einai ena sunolo atomwn. Kai ta atoma einai ta mikra swmatidia poy apoteloun o,ti blepete se ayto ton kosmo. Oi moriakoi ypologistes 8a xrhsimopoioun ta moria ths ulhs san ypergrhgoroys diakoptes on/off. Otan o diakopths einai ON shmainei 1, kai otan einai OFF shmainei 0. Ola ta programmata se ayton ton kosmo basizontai sto dyadiko susthma.
O parakatw pinakas deixnei th proodo kai tis mellontikes taseis proodoy twn chips twn ypologistwn.
Advancement of chip capabilities in future
********************************************
+--------------------------+---------+---------+---------+---------+--------+---------+
| Item/Year | 1997 | 1999 | 2001 | 2003 | 2012 | 2020 |
+--------------------------+---------+---------+---------+---------+--------+---------+
| Feature size(micron) | 0.25 | 0.18 | 0.15 | 0.13 | 0.05 |< 0.00001|
+--------------------------+---------+---------+---------+---------+--------+---------+
| Wafer size(mm) | 200 | 300 | 300 | 300 | 450 | Mol/Bio |
+--------------------------+---------+---------+---------+---------+--------+---------+
| Min Operating Voltage | 1.8-2.5 | 1.5-1.8 | 1.2-1.5 | 1.2-1.5 | 0.5-0.6| < 0.001 |
+--------------------------+---------+---------+---------+---------+--------+---------+
| Max power dissipation | 70 | 90 | 110 | 130 | 175 | 600 |
+--------------------------+---------+---------+---------+---------+--------+---------+
| On-chip frequencey (MHz) | 750 | 1,250 | 1,500 | 2,100 | 10,000 | > 50,000|
+--------------------------+---------+---------+---------+---------+--------+---------+
| DRAM capacity | 256 MB | 1 GB | 2 GB | 4 GB | 256 GB | > 1000GB|
+--------------------------+---------+---------+---------+---------+--------+---------+
Opws blepete, to yliko einai ychlhs texnologias kai shmantiko enw to logismiko einai ligotero duskolh texnologia. Ara, h kataskeyh ylikou/ylikwn-aga8wn einai zwtikhs shmasias gia thn e8nikh oikonomia! Etaireies opws oi Compaq, Dell, Sun Microsystems, HP, IBM poy kataskeyazoyn ypologistes einai oi kurioi syneisferontes sthn oikonomia ths Amerikhs shmera kai sto mellon!!
Apo thn allh, ka8e xwra anejairetws ston kosmo anaptussei/ftiaxnei logismiko. Sthn pragmatikothta, opoiosdhpote ston kosmo me ena mikro PC xamhlou-kostoys mporei na dhmioyrghsei ena susthma mias bashs dedomenwn san thn Oracle . Alla 8a toy epairne 10 xronia (o diakomisths ths Oracle einai peripoy 10 an8rwpo-eth doyleia). Ena an8rwpo-etos einai ena atomo poy doyleuei me plhrh apasxolhsh gia ena oloklhro etos. An 10 an8rwpoi ergazontai gia 10 eth tote exoyn jodeytei 10 an8rwpo-eth.
Baseis opws oi Oracle, Informix, Sybase, IBM DB2 (Unix) grafthkan se glwssa "C" kai ta ektelesima dhmioyrgh8hkan metaglwttizontas ton kwdika kai meta apostal8hkan stoys pelates. Oi baseis Oracle, Sybase, Informix einai programmata 100 % "C"!!
Mia kai exei ginei pollh doyleia sthn PostgreSQL ta teleytaia 12 xronia, den exei nohma janadhmioyrghsoyme apo thn arxh mia allh bash poy na ikanopoiei to protypo ANSI/ISO SQL. Einai megalo pleonekthma na xrhsimopoihsoyme ton yparxonta kwdika kai na pros8esoyme ta xarakthristika poy leipoyn h pros8hkes sthn PostgreSQL kai na arxisoyme na th xrhsimopoioume amesws.
H PostgreSQL den einai apla mia dwrean bash alla ena kalhs poiothtas 'Proion Internet'. Problepetai oti h zhthsh proiontwn "Made By Internet" 8a ayjh8ei ek8etika mia kai einai ikano na diathrei ychlh poiothta, xamhlo kostos, ejairetika megalh bash xrhstwn kai atomwn poy anaptussoyn kwdika. Ayta ta e8nh poy de xrhsimopoioun ta proionta 'Made By Internet' 8a xasoyn sobara thn "Epanastash World-wide Internet" kai 8a meinoyn polu pisw apo tis alles xwres. O logos einai oti to idio to "Internet" einai h megaluterh etaireia paragwghs logismikou se olo ton kosmo!