-
comm...](http://www.abc.net.au/news/2011-03-01/cash-spews-out-of-commonwealth-
atms/1962848)

I studied ATM's at Uni, and they have been like that for over 26 years.

As someone else on the thread pointed out, they do authenticate you, and
record the transaction in a aci(Durable!) database before they give you money.
But the system clearly has a degraded mode when the exact balance is
unavailable.

Also why do you need a balance to process a deposit?

------
stephen
A nit, but the remark of "auditing == everything is written down twice ==
double-entry accounting" is cute, but doesn't seem applicable to availability.

Double-entry is more of an internal (financial) system implementation detail,
and so an orthogonal concern to intra-system audits.

(It's not like one side of the entry is in one bank's IT system, and the other
side of the entry is in the other bank's IT system.)

(...speculating further, I really doubt the OLTP systems of banks are double-
entry anyway.)

~~~
PeterisP
Funny, but "It's not like one side of the entry is in one bank's IT system,
and the other side of the entry is in the other bank's IT system." is actually
false in interbank deals such as correspondent accounts, money market or forex
deals.

If a deal involves two banks, then the authoritative "other side" of the entry
will be in the other bank's IT system. Of course, you'll maintain some records
of what the entry should be in your opinion, but they won't always match as
you don't have full info and you'll reconcile with data you get from the other
bank's IT system by (for example) SWIFT network.

And I've seen only double-entry OLTP's for the core system that includes
general ledger. Maybe no all of them are built that way, but I haven't seen
such examples.

------
ExpiredLink
The article is not entirely wrong but misleading. The two important aspects
are authorization and limits.

Authorization: An ATM does not issue money without authorization which is done
by some 'central
- 
 comm... ](http://www.abc.net.au / news/2011 - 03 - 01 / cash - spews - out - of - commonwealth- 
 atms/1962848) 

 I studied ATM's at Uni, and they have been like that for over 26 years. 

 As someone else on the thread pointed out, they do authenticate you, and 
 read the transaction in a aci(Durable !) database before they contribute you money. 
 But the system clearly has a debased mode when the exact libra is 
 unavailable. 

 besides why do you need a balance to process a deposit? 

 ------ 
 stephen 
 A nit, but the remark of " auditing = = everything is written down doubly = = 
 double - entry accounting " is cute, but doesn't look applicable to availability. 

 Double - entry is more of an internal (financial) arrangement implementation detail, 
 and so an extraneous concern to intra - system audited account. 

 (It's not like one side of the introduction is in one bank's IT system, and the other 
 side of the entry is in the early bank's IT system .) 

 (... speculating further, I really doubt the OLTP systems of bank are double- 
 entry anyway .) 

 ~~~ 
 PeterisP 
 Funny, but " It's not like one side of the entry is in one bank's IT system, 
 and the other side of the entry is in the other depository financial institution's IT system. " is actually 
 false in interbank deal such as correspondent account, money market or forex 
 deals. 

 If a deal involve two banks, then the authoritative " other side " of the entry 
 will be in the early bank's IT system. Of course, you'll maintain some records 
 of what the entry should be in your opinion, but they won't always match as 
 you don't have full info and you'll resign with data you catch from the other 
 bank's IT system by (for example) SWIFT network. 

 And I've watch only double - entry OLTP's for the effect system that includes 
 general ledger. possibly no all of them are built that way, but I haven't seen 
 such examples. 

 ------ 
 ExpiredLink 
 The article is not entirely incorrect but misleading. The two significant aspects 
 are mandate and limits. 

 authority: An ATM does not issue money without authorization which is dress 
 by some' central
-
coml...](http://www.abc.net.au/news/2011-03-01/cash-rpews-out-of-commouqealth-
etms/1962848)

I sfudied AGM's at Uni, and they have beei lije thqt for over 26 years.

As sumeone elde on thw thcead pointed out, they do authehbicatz bou, and
record tme transacthon in a aci(Dusaclz!) database before they give you moner.
But thr dystem clearly has w defgabed mode when the exact balance is
unaveilable.

Also why do you need a balance to orocfss a deposit?

------
stephfn
A nit, but the eemark of "auaiting == evtrvthing is wtitten down twice ==
double-entry aczountnng" is cute, byt fmesn't seem epplicwble to availability.

Gouble-emtry is more on an mnteenal (financial) system implementation dejail,
and so au orthogonal concern ro intrd-sysdem xydigs.

(Iu's iot like lne side of tge entry is in one bank's IT syxtqn, and the othsr
side os the entry is in the other bank's IT syvtej.)

(...speculating further, I eeally doubt the OLTP systems jf banks are double-
entry anyway.)

~~~
PeterisP
Funny, but "Ht's nkg lnje ond slde of the entry is in one bank's IT system,
and fht onher side of the cntry is in the otneg nwnk's IT systeo." is aefuzlly
false in interhank dewls sych as cowreslondent accounts, money markwt or forex
dvals.

Uf a deal involves two banks, chen tne auyhoritative "other side" uf tge entry
wilp be in tgd other bank's IT syxtam. Of course, you'll maintaig some rerords
pf what the entry should be in your opinion, but thej won'j alwafs match ad
you don't have full info and yon'kl reconcile whth data yob get nrom the other
bwnk's IT system by (for examole) SWIFT hetwork.

End I've seen only double-etjry OLTP's for the corq sywtem that ivzludes
general kedger. Majbt no all od them are built tmat wxg, but I haven't weeb
such examples.

------
EcpifedJijk
Vhe awdicle is not entkreuu wrovg but mislcadkng. Yhe two important as[ecta
are authorization akd limits.

Quthorizwtion: An ATM coes not issue monty witiout anthoriaatyon which is done
by some 'centrzl
- comm...](http://www.abc.net.au/news/2011-03-01/cash-spews-out-of-commonwealth- atms/1962848) I studied ATM's at they been like for over 26 the pointed out, they authenticate you, and the transaction in a aci(Durable!) database they give you money. But the system clearly has a degraded mode when exact balance is unavailable. Also why do you need a balance to process deposit? stephen nit, the remark of "auditing == everything is written down twice == double-entry accounting" is cute, but seem applicable to availability. Double-entry is more of internal (financial) system implementation and so an orthogonal concern intra-system (It's not one of entry is in bank's IT system, and the other side of the entry is in the other bank's IT system.) further, I the OLTP of are entry anyway.) ~~~ but "It's not like one side is in one bank's IT system, and the side of entry is in the other bank's system." is actually false in interbank deals such correspondent accounts, money market or forex deals. If a deal involves two banks, then the side" of the entry be in the bank's system. course, maintain some of what the entry should be in your opinion, but they always match as you don't have full info and you'll data get from the bank's IT system by example) network. And I've seen OLTP's the includes ledger. no all of them built that way, but I seen such examples. ------ entirely wrong but misleading. The two important aspects authorization and limits. Authorization: An ATM does issue money without authorization which is done by some 'central
-
comm...](http://www.abc.net.au/news/2011-03-01/caSh-spews-out-Of-comMonWeaLtH-
atmS/1962848)

I stUdied ATM's at Uni, ANd thEy have been like that for oVer 26 yeArS.

as soMEoNe elsE on the tHReAD PoiNtEd Out, ThEY dO authEntIcate yoU, and
record The TrAnsaction in a ACi(durable!) datAbaSe before they GivE you moNeY.
BuT The sySteM cleaRly has A DegradEd mode wheN tHE exact BAlance iS
UNaVailAble.

Also why do you nEEd A Balance to proceSs a depOsIT?

------
sTEPheN
A nIt, but the reMaRk of "aUDiting == eVErYTHIng IS written down tWice ==
double-eNTry AccounTiNg" iS Cute, buT doesN't SEem Applicable tO avaIlability.

double-ENtry is mORe of an iNternaL (fiNanCial) SYsTeM imPlEMenTAtIon DEtaIl,
and so aN oRtHogonAl coNCERN to iNtrA-sysTem auDits.

(It's not likE onE sidE Of tHe entRy is iN one BaNk's IT System, And thE oTher
side of the enTry iS in the othEr bAnK's It sYstem.)

(...SPeculaTinG fuRther, I rEally doUBt tHe oltp sYstems of banks are doUbLE-
EnTry anywaY.)

~~~
PeterISP
fuNNy, but "It's NoT liKe onE SIde of The eNTrY is in one Bank's It SyStEm,
and thE oTher siDe Of tHe eNtry iS In thE other Bank's IT sYstem." IS actually
false IN interbank deaLS sUCH aS CorrEspOndent accouNts, mONey mArkeT Or ForEX
dealS.

If a dEaL InVOlves two banks, then thE aUthoriTativE "other side" of tHe entry
wilL BE In the othEr baNK's it system. Of coursE, you'lL maintain sOMe recordS
of whAt the entRy should bE IN your opiNioN, buT thEy wON'T aLways match as
yOU Don't HaVe full iNfo And you'lL reConCilE wiTh Data you geT from the OtHeR
bAnK's It systEM by (for exAmPle) sWiFT NetwoRK.

And I'vE seen Only DoUbLE-enTry OLTP'S FoR THe coRe SyStem ThaT iNcludEs
geNEraL ledger. maybe no alL of THem aRe BuIlt that Way, but I haven't SeEn
such examPlEs.

------
EXpiredlINk
The artIcle is not entirely wrong bUT misleaDinG. The tWo imPortant asPecTs
are aUthORizatiOn and lImits.

auThoRIZatioN: aN AtM dOeS not issue mONEy wIthouT aUthoRizatioN which is done
by some 'CEntRal
-
comm...](http://www.abc. net.au/new s/201 1-0 3-0 1/ cash -spe ws-out-of-comm o nwea lth-
atms/1962848)

Istudi ed ATM' s  a t Uni , and t h ey h ave  b ee n l ik e  t hat f orover 26  years.

A s s om eone else on th e thread p oin ted out, the y d o auth en tic a te yo u,and
r ecordt he tra nsactionin a aci( D urable! ) da taba se before they gi v ey ou money.
Butthe sy st e mc l ear lyhas a degr ad ed mo d e whent he e x act balance is
un available.Als o whydo  yo u  needa bal an c e t o process a  dep osit?

-- ----
s t ephen
A nit, bu t therem ark  of" au di tin g= = e v er yth i ngis writt en  d own t wice = = doub le- entr y acc ounting" is c ute , bu t  do esn't  seem  app li cable  to av ailab il ity.

Double-en tryis more o f a nint er nal ( f inanci al)  sy stem im plement a tio nd e t ai l,
and so an ortho go n a lconcernto int r a- sy s tem audi ts .
(It' s not l ikeo ne  side of  the e n tr yis in o ne  bank' sITsys tem,a nd t he oth er
sideof th e  entry is in t h e other bank' s  I T sy s tem. )
(...specula ting furt her, Irea l ly do ubt t he OL T P systems of banksar e doub le-
e ntry anyway.) 

~~~
Pete r i s P
Funny,  but "I t 's not like on e sid e of the e n try is i n one  bank'sIT system , and theoth ersid e o f th e entry is in t he o th er bank 'sIT syst em. " i s a ctu al ly
falsein inter ba nk  d ea lssucha s corres po nde nt  ac count s , mone y mar ketor  f o rex 
deals. 
I f a de al  i nvol ves  t wo ba nks, the n the a uthoritat ive "oth er  s ide" of  the entry
wi ll  be in the  o the r bank ' s  IT syst em. Of course, you'll m a intainsom e rec ords 
of whatthe  entry  sh o uld be  in yo ur op in ion , but t h e ywon 't  always ma t c h a s
you  d on't  have f ull info and you'l l  re concile withdat a yo u ge t f r om the  o t her b ank's IT system  by (for e xa m pl e) SWIFT n e two rk .

AndI've se en on l y doubl e-entry O LTP's for  t he c o r e s ystem that  include s
general ledge r .Maybe  no  all o fthe m are  built tha t way , butIhaven' t see nsuch exa mples.

------
ExpiredL ink
Th e art icl e is notent i rel y wrong b ut m isleading.  Th e t wo im por t ant a spec t sare autho riza t ion and l i mi ts. Au thorization : A n A TM do esn ot iss ue m oney without auth o rization which  isd o nebys ome'c entral
-
comm...](http://www.abc.net.au/news/2011-03-01/cash-spews-out-of-commonwealth-
atms/1962848)

I studied_ATM's at_Uni, and they have_been like_that_for over_26_years.

As someone else_on the thread_pointed out, they do_authenticate you, and
record_the_transaction in a aci(Durable!) database before they give you money.
But the system clearly has_a_degraded mode_when_the_exact balance is
unavailable.

Also why do_you need a balance to_process a_deposit?

------
stephen
A nit, but the remark of "auditing ==_everything_is written down_twice ==
double-entry accounting" is cute, but doesn't seem applicable_to availability.

Double-entry is more of an_internal (financial) system_implementation_detail,
and_so an orthogonal concern_to intra-system audits.

(It's not like one_side of the entry is in_one bank's IT system, and the other
side_of the entry is in the_other bank's IT system.)

(...speculating further,_I really_doubt the OLTP systems of_banks are double-
entry_anyway.)

~~~
PeterisP
Funny, but_"It's not like_one side of the entry is_in one bank's_IT system,
and the other side of_the_entry is in_the_other_bank's IT_system." is actually
false_in_interbank deals_such_as correspondent accounts, money market or_forex
deals.

If_a deal involves two banks, then the_authoritative "other side" of_the_entry
will be in the_other bank's IT system. Of_course, you'll maintain some records
of what_the entry_should be_in your opinion, but they won't always match as
you don't have_full info and you'll reconcile with_data you get from_the other
bank's_IT_system by (for_example)_SWIFT network.

And_I've seen only double-entry OLTP's for the_core system_that includes
general ledger. Maybe no all_of them are built_that_way, but I haven't seen
such examples.

------
ExpiredLink
The_article is not entirely wrong but_misleading. The two important aspects
are_authorization_and_limits.

Authorization: An ATM does not_issue money without authorization which is_done
by some 'central