yi^gefljagVjigi
tftuan Java xudng lap
TS. e^ng Hoai Bac G I O I THIEU
dang va se cung cap cdc loai hinh dich vu da dang trong nhidu linh vuc eua cuflc sdng, mang nhidu tifln ich cho ngudt su dung. Tuy nhifln, Viet Nam van chua thuc su chii ddng hong viee thidt ke chd tao va xay dung mflt sd san pham ddu cudi di dflng thflng minh phue vu ddi sdng xa hdi, phu thuflc nhidu vao cflng nghe nudc ngodi. Cdc thiet bi ddu cudi di dflng thflng minh dua tren ha tang mang vien thong hien nay rdt phong phu nhu: dign thoai
se CO nhieu thidt hi de:
hfln xe hoi (Tele
ban hdng hi dflng (POS: Point of Sale); phuc vu giao due va du lich nhu Edutalment. Touristaiment; phuc vu an ninh, quan su. Dd phat thdn cdc ddng hiidt hi nay phuc vu thi tnrdng Vipt Nam, hg giup cdc nha thiet ke mgt each nhanh nhdt dua san phdm ra thi trudng, theo kinh nghiflm hen the gioi, rdt can cd nhimg ndn tang phdn ciing kem theo cac driver hd hg, gpi la Platform - da nang hg giiip kha nang
thidt kd, lap trinh ca phan mdm va phan cimg cho thidt bi.
CAC X U H U O N G P H A T T R I E N T H I E T KE P L A T F O R M C H O C A C T H I E T B I C A M T A Y T H O N G M I N H
Ddi VOL linh vue Undt ke nen tang platfoim cho cdc thidt bl dl ddng cam tay, hfln thd gidi hifln nay cd the chia thanh 02 xu hudng:
Phat t r i e n tCC dau
Xu hudng phat trien tii ddu Id xu thd chu dao hong cac thiet hi tufln nay. Cdc cflng ty thiet kd san pham se tu thidt kd phdn cimg, bao gdm cdc mach didn tit va phan mem iing dung. Ddi voi he dieu hdnh cua thiet bi, cac cflng ty cd the tu phdt trien he didu hanh neng cua minh nhu RIM, lOS, Symbian..., diing cac he didu hanh ma ngudn md nhu Lmux, Android, hoac mua lai hfl didu hdnh cua cdc hang khdc nhu MS Wmdows Mobile.
Trong lmh vuc dien thoai di dflng vd mdy tinh bang, cdc hang nhu Nokia, Sony, Samsung, LG, Motorola, Apple deu tu phdt trien cdc tliiet bi, chip rieng eua minh. Nhung thidt kd nay ddu khflng dupc cdng bd ra ngodi. Nhin chung, cdc hang ndy ddu dimg cdc ctup Ioi ARM cho thiet bi cua minh. Ken nay, cdc he dieu hdnh phd bidn nhdt la iOS cua Apple vd Android cua Google. Ddi vdi Android, viflc phdt tridn img dung se duoc thue hidn bdng ngon ngu Java. Sau dd, chuang trinh dugc bifln dich vd chay qua mgt dang tuang duong may do Java {JVM:
Java Virtual Machme] ggi la Dalvik Virtual Machine dd ehuyen cdc Iflnh ndy thanh cae md mdy cua kidn true ARM. Viflc thflng dieh nay duong nhifln Idm giam tdc dd thuc thi so vdi cdc ctup xu ly true hdp ldnh Java.
Trong cdc thidt bi di ddng cdm tay, dien thoai di dflng vd mdy tinh bang Id hai thidt hi phd bien
nhdt. Nhd cd thidt ke vol nhidu thu vifln co sdn di kem cdc bg SDK, thu vien cua he didu hdnh nhu iOS, Android, viec phat trien cdc iing dung hdn cdc thidt bi ndy tuang ddi dd dang, sd lugng img dung gia tang nhanh ehong. Tuy ntiien, cdc thidt bi ndy thudng chi Id cdc thiet bi da dung, duoc dimg cho cdc cdng viflc hen lac, giai tri da phuong hdn vd mgt sd edng vide van phdng. Ddi vdi mdt sd thidt bl ehuydn dung nhu cac he thdng ban hdng POS, cac hfl thdng gidm sat an mnh, cae thidt hi hong xe hoac cac thidt bi chuyen dung quan su khdc, ydu edu phdl cd cac ttiiet kd rieng.
Phat trien dUa tren cac nen tang sSn c6 Viec thuc Men thidt kd cae tluet bi di dflng hodn chinh tir ddu ddn eudi ddi hdi sd vdn ddu tu ban ddu ldn, thda gian phat tnen lau, sd lugng rihdn luc nhidu. Ngoai ra. can mflt day chuydn khdng Id tii nghifln cim nhu cdu, nghidn cim vd lua chon cdng nghe, thidt kd, sdn xudt, hidu ctiinh tdi uu va hep tuc phdt tnen cdc thd he ke hdp. Db la mdt sd ly do chinh chi cd cac cong ty da qudc 0 a ldn moi c6 thd thidt kd cdc ttiiet hi tir dau.
Ddi vdi eac edng ty nho, mang thidt bi cdm tay chu ydu tap tnmg vao cac thidt bi chuyen dung, sd luong nhd, yflu cau rieng biet cao, thdi gian dua san pham ra thi trudng phai nhanh. Do vdy, ddi tuong nay thudng khflng thidt ke chip tii ddu ma sir dung cac platform sdn ed de thuc hifln thidt kd eho sdn pham cua miiih. Hudng ndy se het kipm dugc chi phi nghien eiru, thidt kd vd giam thbi 0 a n phat tridn sdn pham. Cac Platform cd sdn thidt kd mdu eho phdn Cling (hardvtfaie reference design), hd didu hdnh nhimg kem theo, driver cho thidt bi vd cdc thu vidn dd lap trinh. Cac edng ty ehi cdn chinh sua mflt sd chi tidt vd mach phan eimg vd phdt tridn thflm cdc ling dung phan mdm hen ndn tang sdn ed Id c6 thd cd cdc sdn pham mdu vdi cdc tinh ndng mong
3 4 TAP CHI CNTT & T T K Y 2 ( 1 0 . 2 0 1 3 )
mudn. Phan thidt ke mach in PCB cung cd thd chinh sua, vfl 1^ dd phu hgp vdi cdc thidt ke giao dien vd ddng gdi. Nhugc diem ciia xu hudng nay Id cdc san phdm se phu thudc vao cdc mach tich hpp IC vd cdc thidt kd sdn cd. Tuy nhifln, khi so sdnh vdi viflc phat tndn tir ddu, vi$c sii dung cdc platfoim sdn ed mang Iai nhidu Ioi ich kmh td hon, dd rui ro giam han. Xu hudng ndy cd the ndi dang dupc phat tndn manh me, ddc bidt Id hong cdc Iinh vue ydu cdu cdc ttudt bi cd tinh chuyfln biet hda cao.
Qua tinh hinh nghien cim hfln thd gidi cho thdy:
- Xu thd nghifln cim thidt kd cdc thiet bi cam tay cd kha nang kdt ndi khdng day idt phat tndn.
- Hdu hdt cdc thiet bi di dflng su dung Java dd phdt tridn cac img dung. Do do, cac bd xit IJ Java cd thd dugc img dung rflng rai. Viflc thidt kd phdt trien cde img dung cho cac thidt bi su dung bfl xu Iy Java sfl don 0an, nhanh chdng hon cdc bd xii ly vdi tap ldnh chuyfln dung.
Chimg tfli dd xuat viflc thidt kd platform hen ndn tang chip xu Iy thuan Java, nhdm ddp iing cdc nhu cau thiet kd phdt then cac thidt bi cam tay hoac cac tluet bi dieu khidn cd kha nang tiiy bidn linh hoat ling diing tai Vipt Nam.
CtNG DUNG JAVA TRONG CAC THIET BI DI DONG
Mdi truong Java la mdt mfli trudng phd bidn nhdt hong cdc ttiiet bi di ddng vdi hon 4,5 ty ttiidt bi hifln nay dang chay hen ndn Java. Tinh phd bidn cua moi trudng Java the hidn qua thdng tm vd cdc hang vd cdc thidt bi su dung Java hong Bang 1.
Khi so sdnh giua cdc Platform, cdc Platform su dung Java nhu Android cd thi phdn phdt tndn nhanh nhat, etiidm gan 2/3 todn bfl thi trudng smartphone. Tai My, Platform nay chidm ddn 80%
thi tnrdng (Ngudn: IDC quy 2 nam 2013). Mac du
Bang 1: Danh gia sudung Java trong cA? thiet bi di dong
Hing Di dflng Google Microsoft Nokia, Motorola
va Samsung LG Apple Research m Motion {RIM)
HTC
Chiing Ioai Phdn cung
Nhidu chiing loal
Nhidu chiing loai
IPhone BlackBerry
Nhidu chiing lo^
Hfl didu hanh (Operatmg System)
Android Windows Mobile Symhian OS, Android
Windows Mobile, Android,...
iPhone OS{Mac OS X) BlackBerry OS Android. Wmdows
Mobile, Symbian
Mfli trudng Cross-OS Web browser Android Browser, Opera Muu, Firefox,...
Intemet Explorer, Opera Mobile Opera Mobile / Mim
Opera Mini, Safan Opera Mml, BlackBerry
Browser Opera Mim,
Sun Java ME Java ME Tests, JavaFX Tech Demo JavaME JavaFX Demo
Java ME, Java ME, JavaFX
Partner
JavaME JavaME
-•
N e t w o r k e d Emb(?ddod Applications M o b i l e
Applicatio .Appticniioilu
RTOS Si]bt:>'st«nis J.ivn .Sollu-nr« Diivers nJik'Renl-TuiieOS IC^iiiel
Hardware Platform
1b*Md on Java procanor*)
.Fiiv;! prncv.s.sor-bii.sed Plutfoiin
^
Android ed mdy ao rieng nhimg viee phdt tnen cac ling dung vdn su dung ngdn ngii Java. Hang Sun cimg phdt trien ndn tang phan mdm JavaFX cho cac thiet bi di dflng thflng mmh. Java ME tii Idu da Id ndn tang mac dinh cho hdu hdt cdc ling dung di ddng. Khdc vdi cdc Platform hien nay ciia Samsung, LG, Nokia,
dua h f l n cac bd v i xii ly Hinh 1- Kign trOc ciia mOt thiSt bj di dOng cdm tay xCr ly thuan Java.
chinh cita cdc hang ndi
udng nhu hitel, IBM, ARM. Cdc bfl vi xu ly nay deu sii dung tap lenh ciia rieng minh va phai sit dung mdt tririh thdng dich Java tnmg gian de hfl hp.
X A Y DLTNG N E N T A N G P L A T F O R M XU"
LY T H U A N J A V A
Vdl xu hudng phdt tndn cdc thiet bi di dpng cam tay ngay mdt gia tang, rihdm thidt kd cua Hoc vifln Cdng nghfl Buu ehinh Vien thdng kdt hpp vdi hang Ajile sd h'uu bfl vi xii ly thudn Java se xay dung mdt kidn tnic Platform-xir ly thudn Java da nang de tao dieu kien thuan loi cho cdc nhd thidt kd ktu phdt trien cdc img dung cua mirth vdi thdi gian nhanh nhdt. Ve ca ban. Platform se gdm 2 phdn: phdn Cling vd phdn mdm, hong dd bp vi xu ly thudn Java la bd xii ly hoat dflng true hep hen mdi tnrdng Java, hat rihan cua Platform. Cdc cflng cu danh cho phdt tridn phdn mdm bao gdm; IDE EcUpse, Optimizmg Linker/Application Builder JEMBuilder - hoan toan midn phi, dfl ddng cho cac nha thidt ke. Thidt kd phdn Cling dupc thuc hifln hen phan mem thiet ke maeh phd bidn hifln nay la Cadence, Synopsys.
Hinh 1 la kidn tnic tdng quan hdn quan didm phdn
mdm eiia mdt thidt bj di ddng cdm tay su dung ndn tang xu Iy thudn Java. He thdng gom nen tang do nhdm thidt kd thuc hien vd phdn iing dung phia hen duge phdt trien bdi eae nha san xudt tliiet bl dl ddng earn tay.
Ndn tang Platform dugc dd xuat sii dung bfl vi xu ly Java Processor cd kha nang xu ly cdc ma Iflnh Java true hep nfln cd thd nhanh hon khoang 4 ddn 10 ldn so vdi cdc chip tuong tu vi bd qua trinh thdng dieh trung gian vd khflng cdn su dung ddn mdy do Java.
Ldi vi xu ly thudn Java thuc thi true hep cdc Iflnh bytecode cua may ao Java JVM, hd trg threading thcii gian thuc hong Java va mdt sd cdc bytecode md rdng hfl h o eho cdc iing dung nhiing da phuong hdn vd ket ndi mang. Ldi cai ttiifln hieu ndng thuc thi Java thdng qua viec thue thi Idp phien dich vd ldp nhdn RTOS. Boi vi cac ma bytecode JVM duoc thuc thi nhu la cdc Iflnh nguyen thiiy nen hieu ndng xu ly Java eua I5i tuong tu nhu ede bfl vi xu ly RISC ktii chay cae chuong trinh C dugc bidn dich. Them vao niia vdi vide ho h p threading Java (cae ham waif, yield, notify, monitor, enter/exit) dugc thue thi bang viflc su dung cdc bytecode md rdng nfln khdng cdn mdt RTOS truydn thdng. Kdt qua ddn ddn thdi 0 a n chuydn ddi ngu canh thread-to-thread duoe giam ddngkd{<lps).
Trong kidn tnic eua Java Core, cthig nhu hdu hdt ede ldi Java da dugc nghidn ciiu ehd tao trudc dd hfln thd gidl, Idi su dung khai ni^m microcode (vi Iflnh) - day la tap Ipnh riflng eua mflt khdi xii ly
361 TAP CHI CNTT & TT KY 2 ( 1 0 . 2 0 1 3 )
Hinh 2: L5i vi xii ly thuSn Java.
bfln hong ciia Ifli - khdi ndy cd kidn tnic RISC. Se cd dnh xa giOa cdc bytecode va cac tap vi I$nh ndy.
Vdl nhhng Iflnh Java don gidn, nd se tuong img vdi mdt vi I$nh. Vdi nhiing ldnh phuc tap, nhu phep todn new dd tao ra mdt ddi tugng mdi thi nd se tuong ling vdl mflt tdp cdc vi Iflnh. Bdng cdch tidp cdn nay, vdi cdc ldnh md lOi RISC bfln hong khflng thuc thi true hdp bdi mdt Iflnh duoc, nd se tao ra mflt hap. Trap ndy sfl dnh xa tdl vimg Microcode Rom dd thuc thi doan chuong trinh tuong img vdi mflt Iflnh cua Java.
Ddy la ndn tdng hudng tdi cac thidt bi di ddng the hfl mdi nfln nfl phai ddp iing nhidu tac vu thdi gian thvic. Cde mat cua Mdn true ptiai du dodn dupc vd mat tiidi gian theo phan tich WCET {Worst Case Execution Time). WCET cang tiidp cang tdt. Bfl xii ly cOng phai dugc thidt kd don gian nhdm tidu tdn cflng sudt thdp vd dd ddng thi;c thi. Bd xir ly thudn Java duoc phdt tridn hodn todn ddp iing dupc ydu cdu ndy.
Vdi myc hflu xdy dung ndn tang Java Piocessoi cho cdc thidt bj cdm tay di dOng nfln ndn tdng ndy phdi tuong thich vdi ndn tdng Java ME. Ndn tang
Java ME Id tdp cae chudn va cdc cdng nghfl dd tao ra mflt ndn tang phii hgp vdi cdc yflu cdu cho cdc thidt hi di ddng, thidt bi hflu dimg, thidt bi nhiing, duoc tao dd giai quydt cac gidi h^n rdng bude khi xay dung cac img dung cho cdc thidt bi nhd. Vdi muc dich ndy. Sun dmh nghia ky thudt Java ME co ban dd phii hgp vdi cdc mfli trudng gidi han vd tao ra cdc iing dung Java chay hdn cac thidt bi nhd vdi kha nang cflng sudt bd xii ly, man hinh vd bd iihd gidl han, cung cdp mflt mfli trudng Unh hoat, manh me cho cdc img dung chay hfln di dflng va cdc thidt bi nhiing nhu mobile phone, PDA, TV set-top box, mdy m, cac img dung M2M (Machme to maclime)...
Java ME bao gdm cde giao didn ngudi sii dung linh hoat, bdo mat cao, cdc chdng giao thiic mang vd hd hg cac img dung offline cung nhu kdt ndi mang. cac img dung dua hfln Java ME la cd kha nang nhiing vao cae thidt bi phdn cimg. Theo dd, ede Idp phdn mem cua Platform se duac xay dung nhdm tudn theo tiflu chudn Java ME duoc quy dinh bdi Sun.
Hd hp kdt ndi tdi cdc mang di dflng thd hd sau
iang 2: Danh gia hieu nang ciia Bo vi xii ly Ihuan Java
Cac phep loan
Tmy cap mang so nguyen Cong Byte
Trii Byte Nhan Byte Cong so nguyen 4 byte Trii so nguyen 4 byte Nhan so nguyen 4 byte Cong so thuc dau phay tinh Tni sd thuc dau phay tinh Chia sd thuc dau phay tinh Cdng sd thuc dau phay dOng Trii sd thuc dau phay ddng Chia sd thuc dau phay ddng Ghep chudi ky tu Khdi tao ddl tuong Tmng binh
Xii Iy thuan Java
@ 166Mhz aJfle RTOS [Phep toan/GiayJ
2.016.492 6.666.666 6.666.666 5.882.352 10.526.315 9.302.325 7.272.727 5.405.405 4.444.444 1.886.792 2.531.645 2.298.850 722.021
12.383 421.052
BomlyARMll Jazelle @566Mh2
Android 1.5 [Phep toan/Giay]
1.692.833 6.915.933 6.496.786 5.794.430 11.283.891 10.719.697 10.209.235 3.898.071 3.457.966 2.187.693 3.248.393 3.152.852 626.883
4.624 75.959
Xu ly thuan Java so voi ARMll
1,19 0,96 1.03 1,02 0,93 0,87 0,71 1,39 1,29 0,86 0,78 0,73 1,15 2,68 5,54 1,41
Xii ly thuan Java so vdl ARMll theo
tdc do Mhz 4,06 3,29 3,50 3,46 3,18 2,96 2,43 4,73 4,38 2,94 2,66 2,49 3,93 9,13 18,90 4,80 Ket q u a : Xu' ly t h u a n Java = 4 , 8 0 x hieu nang tot hdn A R M l l
duoe thuc hien bang viec su dung giao dien USB OTG - giao difln pho bidn dugc dimg hong ket ndi tdi cdc module GSM/3G/4G - cho phep Platfoim dfl ddng giao tidp phdn cimg tdi cdc module ndy, thuc hien ket ndi eac thiet bi su dung Platform tdi cdc mang di dflng the he sau. Thu vien phan mem hd ho tuan theo chudn Java ME cho phep linh hoat hong phat trien cde img dung lifln quan ddn ket ndi mang
D a n h gia hieu nang cua Platform xuT ly t h u a n Java
Dd mmh chiing hieu nang oia Platform xu ly thuan Java, chimg ta hay xem ddnh gia duac tien hdnh bdi nhdm nghifln ciiu ve hieu nang cua cac bfl vi xii ly Java ddl vdl bd VI xii ly ARMl I - bfl vi xii Iy dugc sii dung hong hau het cac ndn tang cac thidt bi cdm tay hidn nay:
Theo Bang 2, hiflu nang cua bfl vi xii ly Java cd the gap gdn 20 lan so vdi bfl vi xu ly ARMl 1 cd hfi hg tang tdc Java. Viec su dung Platform dua hfln bd VI xu ly Java Processor 32 bit hong phat tridn cdc tliiet bi di ddng cam tay giiip giam chi phi nhd tdn dung cac he didu hdnh hen ndn Java, cde cflng cu phdt tiidn phan mem mien phi eiia Sun hay Oracle.
Dac didm ndi bat niia khi su dung cdc bfl xii ly Java eho cdc thidt bi di ddng cam tay, cdc nhd ldp trinh ling dung phdn mem se phdt tridn rdt nhanh cdc ling dung ciia minh ma khdng can quan tdm ddn cdc kdt ndi cdu tnic phdn ciing.
Nhu v^y, viee iing dung vi xii Iy thudn Java hong thidt kd eac ttudt bi di ddng cd nhidu uu didm vuot
381 TAP CHI CNTT & TT KY 2 ( 1 0 . 2 0 1 3 )
hdi, 0up cdc ehuong trinh vidt hfln ndn Java chay nhanh hon, vide phat tndn chuang trinh dfl ddng hon, ddng thdi giam thidu difln nang hflu thu. Ddy ciing Id kdt qua ndi bat ciia nhdm nghien ciiu Hgc vidn Cflng nghd Buu chinh Vidn thdng vd cung Id mflt hong cdc xu thd phdt tridn manh me hen the gidi hien nay.
Cdc san pham du kidn iing dung Platform cho cdc thidt bi di ddng cdm tay dua vdo xii ly thuan Java bao gdm:
- Cdc thidt hi di ddng thflng minh hfln cflng nghfl 3G/4G.
- Cdc sdn phdm di ddng cam tay chuyen dung su dung dich vu vifln thflng.
- Cdc thidt bi giai hi hoc tap da phuong tien Edutainment.
- Cdc thidt bi ket ndi xu Vy trung tdm dua hdn ha tdng vidn thdng hong cac giao dich thanh todn (vi du Uiidt bi bdn hdng POS: Pomt of Sale).
-- Cdc thidt bl qudn ly gidm sdt thu thap du hflu, truydn nn cam tay.
Viflc thidt ke Platform bao gdm ca phdn cting va phdn mdm dua hdn bd xit ly thudn Java 32~bit ldn ddu hen duoc nghifln ciiu tai Viflt Nam cho cdc thidt bi thflng mmh se mang lai mflt tipn ich rdt ldn eho eac nha phdt tndn iing dung vd gidm thdi gian cung nhu tao dd linh hoat hong thidt
kd cd phdn ciing vd phdn mdm img dung, dac bi$t khi cflng nghfl dl dOng phat tndn rdt nhanh tai Vidt Nam nhu hidn nay. Kdt qud ciia nghidn citu img dung thudn Java da t^o mdt ndn tang
chung bao gdm cdc thu vien day du cho cdc thidt bi duoc chia se vdi cdng ddng tiiidt kd difln tu cimg nhu phdt trien iing dung giup cho cac thiet ke hoac sua ddi eac chitc nang cua cdc thidt bi thdng minh, thidt bl nhimg duoc thue hifln nhanh chdng, linh hoat vd hieu qua. Ngudi lap trinh phdn mdm dii khdng cd Men thiic chuyen sdu vd phdn ciing cd the dfl ddng phdt tndn cdc img dung hfln nen phdn cimg vdi mdi trudng lap trinh quen thudc.
Tai lieu tham khao
[1], Ajile Systems, Inc, Whitepaper, www.a]ile.com [2]. Sun Inc, Wiiitepaper, httpL//java.SLr.com
[31. ARM inc., Whitepaper "Jazelle for Execution Environments", www. ann.com.
[41. ARM Inc., Whitepaper"High performance Java on Emtjedded devices", wfww.arm.com.
[ 5 ] . PANGS C. LEKKASAS Network Rocessors: ArcfiitectuBS.
Protocols. andPlatform. McGraw-Hill, 2 0 0 4 ,
[61. ALEX D O B a i and EDWARD H. CURRIE, InboAction to Mixed-Signal Entedded Design, Sfwinger, 2 0 1 1 .
[ 7 ] . M. XHOEBERL, JOP: A Java Optimi^ Rocessor for Entedded Re^-Time Systems, PhD thesis, Vienna University of Technology, 2 0 0 5 .
[ 8 ] . HALL, u .Micrcprocessors and Interfacing - McGraw-Hill, New York, 2 0 0 6
[91. JOHN CATSOULIS, Designing Embedded Hardware, O'Reilly, 2 0 1 2 .
/ ' [101, T NOERGAARD, / , NEWNES, Entedded
Systems fifchitectue - A Canprehensive Guide for EngineersandPro^ammers, 2™^Ed.2012.
