in the following description , reference is made to the accompanying drawings which illustrate several embodiments of the present invention . it is understood that other embodiments may be utilized and mechanical , compositional , structural , electrical , and operational changes may be made without departing from the spirit and scope of the present disclosure . the following detailed description is not to be taken in a limiting sense , and the scope of the embodiments of the present invention is defined only by the claims of the issued patent . some portions of the detailed description which follows are presented in terms of procedures , steps , logic blocks , processing , and other symbolic representations of operations on data bits that can be performed on computer memory . each step may be performed by hardware , software , firmware , or combinations thereof . it will be understood that other suitable database structures to those described may be utilised and that other suitable memory structures besides databases may be utilised . any examples of a database given are thus illustrative of arrangements for the storage of information . similarly , examples of network topology are illustrative and other topologies may be used . referring to fig1 , there is shown a gaming system 2 suitable for implementing the present invention . a server 4 is provided , typically in an operations centre of a casino or other gaming establishment , but the server 4 could be located in other locations such as a regional data centre supporting a plurality of gaming establishments or venues in which entertainment devices such as gaming machines are located . the server 4 is connected by a communications network 6 to a plurality of entertainment devices such as gaming machines 8 . hereafter the term gaming machine is used as an example of an entertainment device . in fig1 , four such gaming machines are shown , though it will be understood that other numbers , for example many more , for example hundreds or thousands of machines ( as the network permits ) may be connected to the server through the network 6 . the network 6 may comprise the internet or any other suitable network , either wired or wireless . for the purposes of the present invention , the server 4 comprises a database server . in practice the server may also perform other functionality or form part of a server array or server farm providing a variety of functionality . the server 4 typically includes or is in communication with a code generator such as a random number generator . the server 4 is additionally in communication with a management computer 10 by which information may be added to the database subject to suitable authorisation and permission controls as will be understood by those familiar with such technology . the management computer 10 is shown in fig1 as being directly connected to the server 4 , but more typically the management computer 10 will access the server 4 by way of a connection over a network . the management computer may itself include additional peripherals such as a keyboard , a scanner and a printer . elements of a gaming machine 8 suitable for use with the present invention are shown in fig2 . the gaming machine 8 includes a main processor running a suitable operating system for managing a plurality of peripherals . one such peripheral is a display unit 22 for presenting a game to a player . such a display unit 22 may take the form of a cathode ray tube , an lcd display a plasma screen or other suitable display . a credit unit 24 which controls and validates payments from one or more payment peripherals is also included . such payment peripheral ( s ) include at least one reader for reading an information carrier and may also include a coin acceptor , note acceptor , credit card or debit card reader or other electronic payment interface . the gaming machine 8 is also provided with a payment unit 26 which controls and validates payments from payment peripherals to enable payment of any remaining credit . such payment peripheral ( s ) include at least one information carrier generator and may also include a coin dispenser , a note dispenser , a card writer or an electronic payment interface . the gaming machine 8 further includes output means 28 such as speakers and light arrays for the generation of audio and visual stimuli for players and prospective players . the gaming machine also includes input means 30 such as buttons , a keypad or a touchscreen . the input means 30 may comprise a selection from these and other examples of suitable input means . each gaming machine 8 is also provided with a network connection 32 to enable the processor 20 to communicate with the server 4 over the network 6 . the gaming machine 8 typically comprises a local memory unit 34 . conveniently gaming software may be stored in the local memory unit 34 . conveniently such gaming software may be updated and / or replaced over the network 6 . should a patron of a gaming establishment , hereafter a player , wish to take advantage of the present invention , it will be necessary first for the player to enrol . for example , the player first makes themself known to a cashier and is provided with a form for completion ( step 100 , fig3 ). the form is preferably in machine readable form . in completing the form , the player provides a variety of items of personal information . this information may include information suitable for marketing purposes , such as a mailing address of the player , as well as other information suitable for enabling the correct identification of the player , such as appearance details or other personal data . the information is provided to the server 4 to create an account for the player and to identify the player on future occasions . on this occasion the player also provides credit to the gaming establishment either by payment of currency , by electronic transfer or any other suitable means ( step 102 ). the value of this credit available with which to play is also stored in the database . the player will also be required to provide a first code ( step 104 ). the first code is chosen by the player . the first code may comprise an alphanumeric password . preferably , the first code is restricted in length to four or five characters . in an alternative embodiment , the form may be in electronic form requiring completion ( either by the player or the cashier in response to answers provided by the player ), on a terminal , for example the management computer , in communication with the server . however , to maintain the security of the first code it is preferred that the player enters this information themselves . next , the code generator generates a second code to be associated with the account of the player ( step 106 ). a suitable database table 120 for use with the present invention is shown in fig3 a . a primary id representative of a player account is shown in a first column 122 . the first code chosen by the player is stored in a second column 124 . the second code generated for the player is stored in a third column 126 . the value of credit available to the player with which to play is stored in a fourth column 128 . in an alternate embodiment , the second code may be used as the primary id representative of the player account . an information carrier , such as a ticket or voucher , is generated by a suitable output peripheral , for example in a preferred embodiment the information carrier is a paper ticket or voucher generated by a printer ( step 108 ). the information carrier bears coding identifying the information carrier , for example by reference to the second code . the coding may be an alphanumeric representation of the second code , a barcode representing the second code or another representation of the second code . as will become apparent , the coding does not need to represent the credit available to the player . however , for the benefit of the player , the value of credit available to the player may be displayed on the information carrier for reading by the player . the information carrier is then provided to the player for use with suitable gaming machines in the gaming establishment ( step 110 ). in order to play a gaming machine , the player selects a desired gaming machine 8 and inserts the information carrier . the gaming machine 8 detects the presence of the inserted information carrier ( step 250 , fig4 a ) and then reads or otherwise detects the second code ( step 252 ). for example an optical character reader may read an alphanumeric code or a scanner of known type may read a barcode . if the second code cannot be detected , the information carrier is returned to the player ( step 254 ). conveniently , the display unit 22 and / or the output means 28 may be used to communicate to the player why the information carrier is being returned and to advise the player to seek assistance for example from a staff member of the gaming establishment . once the information carrier has successfully been read and the second code detected , the player is prompted , for example by way of the display unit 22 and / or the output means 28 to enter the first code ( step 256 ). for ease of recall by the player , the first code is typically a short alphanumeric password or a four to six digit numerical code . the first code may be entered by the player by use of any suitable input means . such as by pressing suitable marked areas of a touch sensitive screen , by pressing buttons indicated by the display to represent numbers or letters ( or by pressing buttons to scroll though a display to the correct number or letter ) and pressing another button ( such as a “ play ” button ) to confirm entry of the first code ( or individual first code elements ) ( step 258 ). if the first code is not entered , the gaming machine continues to prompt the player . preferably , the prompt must be responded to within a predetermined time or the information carrier is returned to the player . conveniently , the display unit 22 and / or the output means 28 may be used to communicate to the player why the information carrier is being returned and to advise the player to seek assistance , for example from a staff member of the gaming establishment . once the first code has been entered , the processor 20 contacts the server 4 and provides the server 4 with the first code ( step 260 ). the server 4 then interrogates the database for the second code associated with the first code provided by the gaming machine and returns this second code to the gaming machine ( step 262 ). a comparison of the second code read by the gaming machine and the second code provided by the database is made ( step 264 ). if the second codes do not correspond , the player may again be prompted to enter the first code ( step 266 ). for example a player may have incorrectly recalled the first code or incorrectly entered the first code . however , to prevent fraud , the player is provided only with a set number of attempts to enter the first code correctly . if the set number of attempts is made and the first code is not correctly entered , the information carrier will be retained and a suitable information message displayed or otherwise conveyed to the player . additionally , the gaming machine may signal ( by any suitable means ) for security to attend the machine . if the second codes are identical , the processor will permit the player to play on the gaming machine 8 ( step 268 ). it will be understood that the gaming machine may instead send the second code to the server , requesting the first code for comparison . alternatively , the gaming machine may communicate one or both of the first and second codes to the server , the server making the comparison between the code or codes provided from the gaming machine and the code or codes retained in the database , the server returning a signal indicative of appropriate action , for example to allow play or retain the information carrier and communicate a suitable information message to the player and / or alert security . once the information carrier has been validated , the database may also record the time of use of the information carrier and details of the machine into which the information carrier was inserted . due to the communication of the gaming machine with the server ( as will be described ) data regarding the amount wagered and the time spent wagering by the player may be recorded and accumulated in the database . this data may be used to identify a profile of the player including , but not limited to , indications of the player &# 39 ; s favoured kind of wager , allowing the player to participate in a loyalty scheme ( such as a player point scheme ) or other bonus scheme . the data may also be checked against known data profiles for example to detect wagering patterns indicative of problem gambling , thereby enabling the gaming machine to communicate a suitable notification to the player to seek to cause the player to modify such wagering patterns . in the event that play is allowed several alternate embodiments are now described . in a first embodiment ( fig5 a ) the value of credit is stored in the database held on the server 4 only ( step 300 ). the gaming machine presents the player with the opportunity to play a game , for example by placing a wager on the outcome of an event ( step 302 ). the gaming machine may invite the player to wager varying amounts . for example in the case of a reel based game , the player may be presented with one or more win lines and provided with a choice of stakes , thereby providing the player with the choice of different wagering different amounts on each spin of the reels . similarly in the case of a roulette style game , the player may be provided with a choice of staking level and the ability to choose a betting pattern of their own making . should the player choose to play the game , once a wager has been placed the gaming machine verifies with the server that the value of the wager placed does not exceed the value of credit available ( step 304 ). if the value of the wager placed exceeds the value of credit available the gaming machine clears the wager placed and again invites the player to place a wager . otherwise , the wager placed is allowed ( step 306 ) and the game is played . a determination of the success of the wager is then made by the processor ( step 308 ) and a suitable signal then sent to the server 4 ( step 310 ). if the wager was successful , a signal is sent to increase the value of credit available in the database , this value of credit replacing the previous value of credit available in the database . if the wager was unsuccessful , a signal is sent to decrease the value of credit available in the database by the amount of the wager placed , this value of credit replacing the previous value of credit available in the database . in some cases , the result of the wager will be to return the wager . in these cases , a signal is sent either to increase or decrease the value of credit available by zero . it is advisable to return a signal since the absence of a signal may be interpreted as a failure , for example of the gaming machine or the network . if the gaming machine does not detect selection of a game ( for example by the placing of a wager ) by the player , the gaming machine checks to determine if the player has requested a cashout ( step 312 ). if not , the gaming machine again checks to determine if a game has been selected . if a cashout has been requested , a method to be described subsequently with reference to fig6 is followed . in a second embodiment ( fig5 b ) having validated the authenticity of the information carrier the processor communicates with the server to obtain the current value of credit from the database ( step 320 ). the processor 20 then stores the value of credit in a suitable location in the local memory unit 34 ( step 322 ). any suitable form of memory may be used for this task . the gaming machine 8 then presents the player with the opportunity to play a game , for example by placing a wager on the outcome of an event 324 . the gaming machine may invite the player to wager varying amounts . should the player choose to play the game once a wager has been placed , the processor checks that the value of the wager placed does not exceed the value of credit in the memory ( step 326 ). if the value of the wager placed exceeds the credit available the processor clears the wager placed and again invites the player to place a wager . otherwise , the wager placed is determined to be allowable and the game is played ( step 328 ). a determination of the success of the wager is then made ( step 330 ) and a suitable signal sent by the processor 20 to the local memory unit 34 . if the wager was successful , the processor 20 signals the local memory unit 34 to increase the value of credit stored in the local memory unit 34 , this value of credit replacing the previous value of credit stored in the local memory unit 34 . if the wager was unsuccessful , a signal is sent to decrease the value of credit available stored in the local memory unit 34 by the amount of the wager placed , this value of credit replacing the previous value of credit stored in the local memory unit 34 . in some cases , the result of the wager will be to return the wager . in these cases , a signal is sent either to increase or decrease the value of credit stored in the local memory unit 34 by zero . it is advisable to return a signal since the absence of a signal may be interpreted as a failure , for example of the connection between the processor and the local memory unit 34 . the gaming machine 8 then again invites the player to play . if the gaming machine does not detect selection of a game ( for example by the placing of a wager ) by the player , the processor 20 checks to determine if the player has requested a cashout ( step 334 ). if not , the processor again checks to determine if a game has been selected . if a cashout has been requested , the processor signals the server with the value of credit stored in the memory unit 34 ( step 336 ) and the server causes the database to be updated with this value of credit ( step 338 ). a method to be described subsequently with reference to fig6 is then followed . it will be understood that in this embodiment the database is updated only at the end of each session of play . in a third embodiment ( fig5 c ) having validated the authenticity of the information carrier , the gaming machine then presents the player with the opportunity to play a game , for example by placing a wager on the outcome of an event ( step 340 ). the gaming machine may invite the player to wager varying amounts . should the player choose to play the game once a wager has been placed , the processor 20 communicates with the server 4 to obtain the value of credit from the database ( step 342 ). when the value of credit is returned , the processor stores the value of credit in the local memory unit 34 ( step 344 ). the processor 20 then checks that the value of the wager placed does not exceed the value of credit in the local memory unit ( step 346 ). if the value of the wager placed exceeds the value of credit available the processor clears the wager placed and again invites the player to place a wager . otherwise , the wager placed is determined to be allowable , and the game is played ( step 348 ). a determination of the success of the wager is subsequently made ( step 350 ) and a signal sent to the local memory unit 34 ( step 352 ). if the wager was successful , the processor 20 signals the local memory unit 34 to increase the value of credit stored in the local memory unit 34 , this value of credit replacing the previous value of credit stored in the local memory unit 34 . if the wager was unsuccessful , a signal is sent to decrease the value of credit available stored in the local memory unit 34 by the amount of the wager placed , this value of credit replacing the previous value of credit stored in the local memory unit 34 . in some cases , the result of the wager will be to return the wager . in these cases , a signal is sent either to increase or decrease the value of credit stored in the local memory unit 34 by zero . it is advisable to return a signal since the absence of a signal may be interpreted as a failure , for example of the connection between the processor and the local memory unit 34 . once the local memory unit 34 has been updated , the processor 22 then signals the server 4 with the value of credit in the local memory unit 34 ( step 354 ). the server 4 then causes the database to be updated with this value of credit ( step 356 ). it will be understood that in this embodiment the database is updated following each play of the game . if the gaming machine does not detect selection of a further game ( for example by the placing of a wager ) by the player , the processor 20 checks to determine if the player has requested a cashout ( step 358 ). if not , the processor 20 again checks to determine if a further game has been selected . if a cashout has been requested , a method to be described subsequently with reference to fig6 is then followed . preferably , when the value of credit remaining is zero , the gaming machine will be caused to generate a replacement information carrier , either at the request of the player or in response to detection of this condition by the gaming machine or server as the case may be . the player may then take this replacement information carrier to a cashier &# 39 ; s desk or automated cashier terminal to provide additional value of credit to the player account , validating the provision of credit by confirming the first code . alternatively , the gaming machine when provided with suitable credit units may invite the player to provide additional credit . the cashout process will now be described by reference to fig6 . first it is necessary for the processor 20 to detect a cashout signal ( step 400 ). typically such a signal is generated in response to actuation of a suitable input means , such as a pressing a “ collect ” button . the “ collect ” button may conveniently take the form of an electro - mechanical peripheral or a suitably marked area of a touchscreen . the processor 20 then signals the server 4 to request an updated second code ( step 402 ). the updated second code is preferably provided by the code generator ( step 404 ). the server 4 replaces the second code in the database with the updated second code ( step 406 ) and supplies the updated second code to the processor 20 ( step 408 ). the processor 20 then causes the output peripheral 28 to generate a new information carrier ( step 410 ). the new information carrier bears coding identifying the replacement information carrier by reference to the updated second code . the coding may be an alphanumeric representation of the updated second code , a barcode representing the updated second code or another representation of the updated second code . in an alternative embodiment , for example where the second code is used as the primary id within the database , the updated second code is not generated , and the existing second code is used such that the replacement information carrier bears coding identifying the replacement information carrier by reference to the second code . if the current value of credit is sufficient , the replacement information carrier may then be used to wager again , by inserting the replacement information carrier into a suitable credit peripheral of a gaming machine in the same way as has already been described . in this way the information carriers may be used as currency with which to wager . the player may also increase the value of credit in their account by inserting currency into the machine by way of a suitable credit peripheral . alternatively , if the current value of credit is sufficient , the ( replacement ) information carrier may be redeemed . the replacement information carrier is provided to a cashier &# 39 ; s desk or automated cashier machine ( step 500 , fig7 ). the second ( or updated second ) code on the replacement information carrier is detected ( step 502 ) the player is then prompted for the first code . the first code may be provided by the player by use of any suitable input means ( step 504 ). the second ( or updated second ) code on the replacement information carrier is then compared against the second ( or updated second ) code recorded in the database against the first code ( step 506 ). a determination is then made as to whether the codes match ( step 508 ). if the codes match the cashier redeems the replacement information carrier ( step 510 ). redemption may be by payment of currency , generating a cheque , or electronic transfer to a suitable bank account . if the codes do not match , the player may again be prompted to enter the first code ( step 512 ). however , to prevent fraud , the player is provided only with a set number of attempts to enter the first code correctly . if the set number of attempts is made and the first code not correctly entered , the replacement information carrier will be retained and a suitable information message communicated to the player . additionally , the cashier or automated cashier may signal ( by any suitable means ) for security to attend ( step 514 ). while the invention has been described in detail and with reference to specific embodiments thereof , it will be apparent to one skilled in the art that various changes and modifications can be made therein without departing from the spirit and scope thereof .