PC Architecture topics.doc

8/14/2019 PC Architecture topics.doc

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C Architectureundamentals

2-Bit Architecture

rocessors

Memory and I/O Maps

on-Volatile MemoryBIO!"

us !tandards# I!And PCI

$%AM

%AM and Cache

nterrupts

imers andontrollers

$irect Memoryccess $MA"

erial Ports

Parallel Ports

'ni(ersal !erial '!B"

Floppy

I$) *ard $ri(e

C$-%OM

!mall Comp!ystem Inter+!C!I"

Audio

Video

Assem,ly an.ua.

&echnolo.y &rend


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What is a processor?

Answer

micro" processors are machines that eecute instructions and act on data0

the +ormat and interpretation o+ these instructions are machine dependant -that is to say that a particular ,inary strin. o+ one1s and ero1s mean speci+icthiin.s" to each processor desi.n or architecture0 also microprocessorsaddress memory ith a parallel ,us - the idth o+ that ,us dictates thespeed and the amount o+ addressa,le memory that is possi,le0

that said comtemporary intel processors adhere to either a 32 ,it or 45 ,itarchitecture0 &hose earlier processors com+ormin. to 32 ,its o+ internalprocessin./memory capacity adhere to intel1s ia-32 intel architecture - 32,its"0 It +ollos then that ia-45 is their 45 ,it (ariant - a ne architecture+ound in their itanium series0 ia-45 machines can at ,est only emulate ia-32

code and do so in so+tare thus do so s-l-o--l-y0

ith the mar6et pressures in+licted ,y intel1s ri(al amd and their 45 ,itarchitecture capa,le o+ eecutin. ,oth in 32 and/or 45 ,it modes" intel hadto de(ise a 45 ,it etension to the u,i7uitous ia-320 amd1s 32 ,it eecution isrendered in hardare and thus a competiti(e per+ormer any ia-32 machine0moreo(er amd1s desi.n is more than patchin. or strechin. 32 ,it re.isters to45 ,its0 not ,ein. capa,le o+ ,rin.in. themsel(es to ac6noled.e amd1sinno(ation they intel" call their etension to ia-32 and a.ain I do meanetension not a re-architecture" em45t +or etended memory architecture 45,it technolo.y - it is supposed to adhere to amd1s amd450

amd1s 8.lue-less8 architecture9 ,t9 namely on-die memory m.t unit alon.ith hypertransport interconnect" ,los intels a.in. +ront-side ,usarchitecture aay - ,i. time particularly as you increase the num,er o+processors in the system desi.n0 amd1s desi.n as also created ith dual-core laid out +rom the start thou.h dual-core desi.ns ha(e only recently,een introduced into the mar6etplace ahead o+ schedule"0

hen comparin. ia-32 to amd45 machines don1t .et side-trac6ed ,yprocessor cloc6 speed either0 amd1s desi.n allos them to run at sloercloc6 speed and thus cooler" yet meet or eceed ia-32 per+ormance0

microprocessor

A microprocessor is a computer processor on a microchip0 It1ssometimes called a logic chip0 It is the 8en.ine8 that .oes into motion henyou turn your computer on0 A microprocessor is desi.ned to per+ormarithmetic and lo.ic operations that ma6e use o+ small num,er-holdin. areascalled registers0 &ypical microprocessor operations include addin.9
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su,tractin.9 comparin. to num,ers9 and +etchin. num,ers +rom one area toanother0 &hese operations are the result o+ a set o+ instructions that are parto+ the microprocessor desi.n0 :hen the computer is turned on9 themicroprocessor is desi.ned to .et the +irst instruction +rom the ,asicinput/output system BIO!" that comes ith the computer as part o+ its

memory0 A+ter that9 either the BIO!9 or the operatin. systemthat BIO! loadsinto computer memory9 or an application pro.am is 8dri(in.8 themicroprocessor9 .i(in. it instructions to per+orm0

memory

- Memory is the electronic holdin. place +or instructions and datathatyour computer1s microprocessorcan reach 7uic6ly0 :hen your computer is innormal operation9 its memory usually contains the main parts o+ theoperatin. systemand some or all o+ the application pro.rams and relateddata that are ,ein. used0 Memory is o+ten used as a shorter synonym +or

random access memory %AM"0 &his 6ind o+ memory is located on one ormore microchips that are physically close to the microprocessor in yourcomputer0 Most des6top and note,oo6 computers sold today include at least;4 me.a,ytes o+ %AM9 and are up.radea,le to include more0 &he more %AMyou ha(e9 the less +re7uently the computer has to access instructions anddata +rom the more sloly accessed hard dis6 +orm o+ stora.e0

Memory is sometimes distin.uished +rom storage9 or the physicalmedium that holds the much lar.er amounts o+ data that on1t +it into%AM and may not ,e immediately needed there0 !tora.e de(ices includehard dis6s9 +loppy dis6s9 C$-%OM9 and tape ,ac6up systems0 &he terms

auxiliary storage9 auxiliary memory9 and secondary memoryha(e also,een used +or this 6ind o+ data repository0

Additional 6inds o+ inte.rated and 7uic6ly accessi,le memory are read-only memory %OM"9 pro.ramma,le %OM P%OM"9 and erasa,lepro.ramma,le %OM )P%OM"0 &hese are used to 6eep special pro.ramsand data9 such as the ,asic input/output system9 that need to ,e in yourcomputer all the time0
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RAM Defined

%AM random access memory" is the place in a computer here theoperatin. system9 application pro.rams9 and data in current use are 6ept sothat they can ,e 7uic6ly reached ,y the computer1s processor0 %AM is much

+aster to read +rom and rite to than the other 6inds o+ stora.e in acomputer9 the hard dis69 +loppy dis69 and C$-%OM0 *oe(er9 the data in%AM stays there only as lon. as your computer is runnin.0 :hen you turnthe computer o++9 %AM loses its data0 :hen you turn your computer ona.ain9 your operatin. system and other +iles are once a.ain loaded into%AM9 usually +rom your hard dis60

%AM can ,e compared to a person1s short-term memory and the harddis6 to the lon.-term memory0 &he short-term memory +ocuses on or6at hand9 ,ut can only 6eep so many +acts in (ie at one time0 I+ short-term memory +ills up9 your ,rain sometimes is a,le to re+resh it +rom

+acts stored in lon.-term memory0 A computer also or6s this ay0 I+%AM +ills up9 the processor needs to continually .o to the hard dis6 too(erlay old data in %AM ith ne9 sloin. don the computer1soperation0 'nli6e the hard dis6 hich can ,ecome completely +ull o+data so that it on1t accept any more9 %AM ne(er runs out o+ memory0It 6eeps operatin.9 ,ut much more sloly than you may ant it to0

How Big is RAM?

%AM is small9 ,oth in physical sie it1s stored in microchipmodules" and inthe amount o+ data it can hold0 It1s much smaller than your hard dis60 Atypical computer may come ith 32 million ,ytes o+ %AM and a hard dis6

that can hold 5 ,illion ,ytes0 %AM comes in the +orm o+ 8discrete8 meanin.separate" microchip modules that plu. into holes in the computer1smother,oard0 &hese holes connect throu.h a ,usor set o+ electrical pathsto the processor0 &he hard dri(e9 on the other hand9 stores data on ama.netied sur+ace that loo6s li6e a phono.raph record0

&oday1s personal computers come ith ;4 or more me.a,ytes o+ %AM9usually increasin. in multiples o+ < me.a,ytes0 'sers o+ .raphicapplications usually need 329 459 or ;2< or e(en more me.a,ytes o+memory0 Most personal computers are desi.ned to allo you to addadditional %AM modules up to a certain limit +or eample9 up to 45 or

;2< me.a,ytes"0 *a(in. more %AM in your computer reduces thenum,er o+ times that the computer processor has to read data in +romyour hard dis69 an operation that ta6es much lon.er than readin. data+rom %AM0 %AM access time is epressed in nanoseconds= hard dis6access time is epressed in milliseconds0"

Why Random Access

%AM is called 8random access8 ,ecause any stora.e location can ,eaccessed directly0 Ori.inally9 the term distin.uished re.ular core memory
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&o access the BIO! setup hen the machine +ails to operate9 occasionallya drastic mo(e is re7uired0 In older computers ith ,attery-,ac6ed %AM9remo(al o+ the ,attery and short circuitin. the ,attery input terminals +ora hile did the ?o,= insome more modern machines thismo(e onlyresets the%&C0 !omemother,oards o++er a CMO!-reset?umper0 In yet

other cases9 the ))P%OM chip has to ,e desoldered andthe data in itmanually edited usin. a pro.rammer0 !ometimes it is enou.h to .roundthe C or $&A line o+ the IDC,us o+ the ))P%OMat theri.ht momentdurin. ,oot9 this re7uires some precise solderin. on !M$parts0 I+ themachine lets you ,oot ,ut does not ant to let you into the BIO! setup9one possi,le reco(ery is to deli,erately 8dama.e8 the CMO! chec6sum,y doin. direct port rites usin. debug.exe9 corruptin. some ,ytes o+the chec6sum-protected area o+ the CMO! %AM= at the net ,oot9 thecomputer typically resets its settin. to +actory de+aults0

BIO

Basic Input Output ystem" An essential set o+ routines stored in a chip thatpro(ides an inter+ace ,eteen the operatin. system and the hardare in aPC0 &he BIO! supports all peripheral technolo.ies includin. dri(es as ell asinternal ser(ices such as the realtime cloc6 time and date"0 BIO! settin.sare maintained in a tiny ,attery-,ac6ed memory0

It !tarts :or6in. at !tartup

On startup9 the BIO! tests the system and prepares the computer +oroperation ,y 7ueryin. its con+i.uration settin.s0 It searches +or other BIO!1s

on the plu.-in ,oards and sets up pointers interrupt (ectors" in mainmemory to access those routines0 It then loads the operatin. system andpasses control to it0 &he BIO! accepts re7uests +rom the dri(ers as ell asthe application pro.rams0

A BIO! Can Eet Out-O+-$ate

BIO!s must periodically ,e updated to 6eep pace ith the latest peripheraltechnolo.ies0 I+ the BIO! is stored on a %OM chip %OM BIO!"9 it must ,ereplaced0 Neer BIO!s are stored on a +lash memory chip that can ,eup.raded (ia so+tare0 BIO! replacement as (ery common ith earlier PCs0

!ee BIO! up.rades9 BIO! setupand ,eep codes0
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BIO! InteractionOn startup9 the BIO! searches all peripheralcontrollers in the system to o,tain the currentcon+i.uration9 hich it ma6es a(aila,le to theso+tare0

BIO! Identi+ication
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&ouch!tone !o+tare1s BIO! :iard is a ni+ty utility thatidenti+ies and tests your PC1s BIO! to see i+ it needs to,e updated0 &he pro.ram is a(aila,le at0esupport0com/,iosi/inde20html0 (Screen imagecourtesy of TouchStone Software Corporation,

www.esupport.com)

&hree Must %ead Articles +rom CMP1s &ech:e,

BIO! Could *ide %oot6its

an.a etter# !ol(in. '!B Boot Pro,lems

Phoeni &echnolo.ies Opens 'p BIO! to the Netor6

Find the latest nes9 +eatures and re(ies relatin. to 8BIO!8 +rom

CMP1s &ech!earch0

Fi PC )rrors FastFi Computer )rrors !peed 'p Gour PC in Minutes0 Free$onload0PCFaster0Net

Bios !ettin.sArticle in PC Ma.aine %ead it online0 Free &rialH0eepMedia0com

A,,re(iations

i,rary :ords A,,re(iationsBIO! is short for&

Meaning "ategory

Basic Input Output !ystem Computin.-Eeneral

Basic Input/ Output !ystem

Eo(ernmental-MilitaryCommunity-MediaComputin.-Eeneral

Computin.-Netor6in.Basic Input/Output !ystem Computin.-$ri(ers

Binary Intelli.ence O(erride!ystem

Computin.-Eeneral

Binary Interrupt Output !er(ice Computin.-Netor6in.
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Clic6 hereto su,mit an acronym0

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:i6ipedia

i,rary %e+erence :i6ipediaBIO!For other uses, see Bios.

BIO Basic inp't o'tp'tsystem

Phoeni AardBIO! CMO!non-(olatile memory" !etup

utility on a standard PC

tored on& P%OM )P%OM

Flash memory

"ommon Man'fact'rers& American Me.atrends Phoeni &echnolo.ies

Others

BIO9 in computin.9 stands +or Basic Inp't(O'tp't ystemalso incorrectly
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6non as Basic Integrated Operating ystem0 BIO! re+ers to the+irmare coderun ,y an IBM compati,le PC hen +irst poered on0 &heprimary +unction o+ the BIO! is to prepare the machine so other so+tarepro.rams stored on (arious media such as hard dri(es9 +loppies9 and C$s"can load9 eecute9 and assume control o+ the pc0 &his process is 6non as

,ootin.up0

BIO! can also ,e said to ,e a coded pro.ram em,edded on a chip thatreco.nises and controls (arious de(ices that ma6e up the pc0 &he term BIO!is speci+ic to personal computer(endors0 Amon. other classes o+ computers9the .eneric terms boot monitor9 boot loaderor boot !"are commonlyused0

&he term +irst appeared in the CP/Moperatin. system9 descri,in. the part o+CP/M loaded durin. ,oot timethat inter+aced directly ith the hardareCP/M machines usually hada simple ,oot loader in %OM9 and nothin. else"0

Most (ersions o+ $O!ha(e a +ile called 8IBMBIO0COM8 or 8IO0!G!8 that isanalo.ous to the CP/M dis6 BIO!0

How the BIO %oots

&he BIO! runs o++ the P%OM9 )P%OMor9 most commonly9 +lash memoryhenthe computer is poered on and it initialies and sometimes per+orms thePoer-on sel+-testPO!&"9 a set o+ dia.nostic tests on the hard dri(e9memory9 (ideo9 chipset and other hardare0 !u,se7uently9 it typicallydecompresses itsel+ +rom the BIO! memory space into the system mainmemory and starts eecutin. +rom there0 Nearly all BIO! implementations

can optionally eecute a setup pro.ram inter+acin. the non(olatile BIO!memory CMO!"0 &his memory holds user-customia,le con+i.uration datatime9 date9 hard dri(edetails9 etc0" accessed ,y BIO! code0 &he


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%OM ith BIO!

BIO! is sometimes called +irmare0 Be+ore ;KKJ or so BIO!es ere held on%OMchips that could not ,e altered0 As their compleity and need +orupdates .re9 BIO! +irmare as stored on ))P%OMor +lash memoryde(ices0 &his ))P%OM chip sits on a F:* inter+ace9 ,ut in some neer,oards ))P%OM chips are already sittin. on a neer9 emer.in. inter+acenamed !PI0 ))P%OM chips are ad(anta.eous ,ecause they can easily ,e

updated ,y the user= hoe(er9 the ris6 is that an improperly eecuted ora,orted BIO! update can render the computer or de(ice unusa,le0 &o a(oidBIO! corruption9 some ne mother,oardsha(e a ,ac6up BIO! i0e0 they arere+erred as $ual BIO! ,oards9 Ei.a,ytee(en o++ers a mother,oard ith 7uadBIO!"0 Also9 most BIO!es ha(e a 8,oot ,loc68 hich is a portion o+ the %OMthat runs +irst and is not updatea,le0 &his code ill (eri+y that the rest o+ theBIO! is intact (ia chec6sum9 hash9 etc0" ,e+ore ?umpin. to it0 I+ the ,oot,loc6 detects that the main BIO! is corrupt9 then it ill typically ,oot to a+loppy so that the user can try +lashin. a.ain9 hope+ully ith success0*ardare manu+acturers +re7uently issue BIO! updates to up.rade theirproducts9 impro(e compati,ility and remo(e ,u.s0

)irmware on adapter cards

A computer system can contain se(eral BIO! +irmare chips0 &hemother,oard BIO! typically contains code to access +undamental hardarecomponents such as the 6ey,oard9 +loppy dri(es9 A&A I$)" hard dis6controllers9 '!Bhuman inter+aces9 and stora.e de(ices0 In addition9 plu.-inadapter cards such as !C!I9 %AI$9 Netor6 inter+ace cards9 and (ideo ,oardso+ten include their on BIO!9 complementin. or replacin. the system BIO!code +or the .i(en component0

In some de(ices that can ,e used ,y add-in adapters and actually directlyinte.rated on the mother,oard9 the add-in %OM may also ,e stored asseparate code on the main BIO! +lash chip0 It may then ,e possi,le toup.rade this 8add-in8 BIO! sometimes called an 8option %OM8" separately+rom the main BIO! code0

Add-in cards usually only re7uire such an add-in BIO! i+ they#
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Need to ,e used prior to the time that the operatin. system loads e0.0they may ,e used as part o+ the process hich loads ,ootstraps" theoperatin. system"9 and#

Are not su++iciently simple9 or .eneric in operation to ,e handled ,y themain BIO! directly

Older operatin. systemssuch as $O!9 as ell as ,ootloaders9 may continueto ma6e use o+ the BIO! to handle input and output0 *oe(er9 most modernoperatin. systems ill interact ith hardare de(ices directly ,y usin. theiron de(ice dri(ersto directly access the hardare0 Occasionally these add-in BIO!s are still called ,y modern operatin. systems9 in order to carry outspeci+ic tas6s such as preliminary de(ice initialiation0

&o +ind these memory mapped epansion %OMs durin. ,oot9 PC BIO!implementations scan real memory +rom JC


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In recent years9 ,y ay o+ systems such as ACPI9 the BIO! has ta6en on morecomple +unctions such as aspects o+ poer mana.ement9 hotplu.9 thermalmana.ement9 etc0 &his has led to reneed reliance on the BIO! ,y operatin.systemproducers9 and an increase in compleity o+ BIO! code0 &his in turnhas led to in(ention o+ Intel1s modern )tensi,le Firmare Inter+ace)FI"

hich in itsel+ incorporates BIO!es etended options0 inu supports )FI (iaelilo,oot loader since early 2JJJ0 Microso+tannounced that support +or )FIin :indos Vistaill ,e dropped +or the launch9 ,ut added in a later update+or 45-,it(ersion0

&he Open !ource community increased their e++ort to de(elop a replacement+or proprietary BIO!es and their +uture incarnations ith an open sourcedcounterpart throu.h the inuBIO!and OpenBIO!/Open Firmarepro?ects0!o +ar9 those pro?ects ha(e met ith some success9 ith AM$pro(idin.product speci+ications +or a num,er o+ +airly recent chipsets9 and Eoo.lesponsorin. the pro?ect0 Mother,oardmanu+acturer&yano++ers inuBIO!

net to the standard BIO! ith their Opteronline o+ mother,oards0

*he BIO %'siness

&he (ast ma?ority o+ PC mother,oard suppliers license a BIO! 8core89 andtool6it +rom a commercial third party9 hich creates and maintains such acore0 &he mother,oard manu+acturer then customies this BIO! to suit itson hardare - +or this reason updated BIO!es are normally o,taineddirectly +rom the mother,oard manu+acturer0

+ist of BIO s'ppliers

American Me.atrends AMI" Phoeni &echnolo.ies Aard !o+tare International mer.ed ith Phoeni in ;KK


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,-ternal lin.s

:im1s BIO! Pa.e Aard ,ios identi+ication pa.e *o !tu++ :or6s - BIO!

In+ormation a,out the BIO!9 PO!&9 BIO! reco(ery

&his entry is +rom :i6ipedia9 the leadin. user-contri,uted encyclopedia0 Itmay not ha(e ,een re(ieed ,y pro+essional editors see +ull disclaimer"

/"I

!hort +or Peripheral Component Interconnect,a local ,usstandard de(eloped

,y Intel Corporation0 Most modern PCsinclude a PCI ,us in addition to a more.eneral I!A epansion ,us0 PCI is also used on neer (ersions o+ theMacintosh computer0

PCI is a 45-,it ,us9 thou.h it is usually implemented as a 32-,it,us0 It canrun at cloc6 speeds o+ 33 or 44 M*0 At 32 ,its and 33 M*9 it yields athrou.hputrate o+ ;33 MBps0 Also see #C$%&and #C$ 'xpress0

Althou.h it as de(eloped ,y Intel9 PCI is not tied to any particular +amily o+microprocessors0

IA %'s

Pronounced as separate letters or as eye%sa"0 !hort +or IndustryStandard Architecture bus9 the ,usarchitectureused in the IBM PC/L&

and PC/A&0 &he A& (ersion o+ the ,us is called the A& ,usand ,ecame a

de +acto industry standard0 !tartin. in the early KJs9 I!A ,e.an to ,ereplaced ,y the PCIlocal ,usarchitecture0 Most computersmade todayinclude ,oth an A& ,us +or sloer de(ices and a PCI ,us +or de(ices thatneed ,etter ,us per+ormance0

In ;KK39 Inteland Microso+tintroduced a ne (ersion o+ the I!Aspeci+ication called Plu. and Play I!A0 Plu. and Play I!A ena,les the
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operatin. systemto con+i.ureepansion ,oardsautomatically so thatusersdo not need to +iddle ith $IP sitchesand?umpers0

memory

+ast modified& )riday0 1an'ary 230 4224

Internal stora.eareas in the computer0 &he term memoryidenti+ies datastora.ethat comes in the +orm o+ chips9 and the ord storageis used +or

memorythat eists on tapes or dis6s0 Moreo(er9 the term memoryisusually used as a shorthand +orphysicalmemory,hich re+ers to theactual chips capa,le o+ holdin. data0 !ome computers also use (irtualmemory9 hich epands physicalmemory onto a hard dis60

)(ery computer comes ith a certain amount o+ physical memory9 usuallyre+erred to as main memoryor "0 Gou can thin6 o+ main memoryas anarrayo+ ,oes9 each o+ hich can hold a sin.le ,yteo+ in+ormation0 Acomputer that has ; me.a,yteo+ memory9 there+ore9 can hold a,out ;million ,ytes or characters" o+ in+ormation0

&here are se(eral di++erent types o+ memory#

RAM5random!access memory6&&his is the same as mainmemory0 :hen used ,y itsel+9 the term "re+ers to readandwrite memory= that is9 you can ,oth ritedata into %AM and read

data +rom %AM0 &his is in contrast to %OM9 hich permits you onlyto read data0 Most %AM is olatile,hich means that it re7uires asteady +lo o+ electricity to maintain its contents0 As soon as thepoer is turned o++9 hate(er data as in %AM is lost0 ROM 5read!only memory6&Computers almost alays containa small amount o+ read-only memory that holds instructions+orstartin. up the computer0 'nli6e %AM9 %OM cannot ,e ritten to0 /ROM5programma%le read!only memory6&A P%OM is amemory chip on hich you can storea pro.ram0 But once the P%OMhas ,een used9 you cannot ipe it clean and use it to storesomethin. else0 i6e %OMs9 P%OMs are non-(olatile0 ,/ROM5erasa%le programma%le read!only memory6&An)P%OM is a special type o+ P%OM that can ,e erased ,y eposin. itto ultra(iolet li.ht0 ,,/ROM5electrically erasa%le programma%le read!onlymemory6&An ))P%OM is a special type o+ P%OM that can ,e erased,y eposin. it to an electrical char.e0
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dynamic

%e+ers to actions that ta6e place at the moment they are needed rather

than in ad(ance0 For eample9 many pro.ramsper+orm dynamic memoryallocation,hich means that they do not reser(e memoryahead o+ time9,ut seie sections o+ memoryhen needed0 In .eneral9 such pro.ramsre7uire less memory9 althou.h they may runa little more sloly0

Also see dynamic *T"+and dynamic +0

&he opposite o+ dynamicis static.

RAM

Pronouncedramm,acronym +or random access memory9 a type o+computer memorythat can ,e accessedrandomly= that is9 any ,yteo+memorycan ,e accessed ithout touchin. the precedin. ,ytes0 %AMis the most common type o+ memory +ound in computersand otherde(ices9 such as printers0

&here are to ,asic types o+ %AM#

dynamic %AM $%AM" static %AM !%AM"

&he to types di++er in the technolo.y they use to hold data9 dynamic%AM ,ein. the more common type0 $ynamic %AM needs to ,ere+reshedthousands o+ times per second0 !tatic %AM does not needto ,e re+reshed9 hich ma6es it +aster= ,ut it is also more epensi(ethan dynamic %AM0 Both types o+ %AM are olatile,meanin. that theylose their contents hen the poer is turned o++0

In common usa.e9 the term "is synonymous ith main memory9the memory a(aila,le to pro.rams0 For eample9 a computer ith


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RAMast modi+ied# Monday9 May ;

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