Abstract:
A method of managing code-tracing data is described. The method comprises the steps of: receiving code-tracing data from an executing software component; adding the received code-tracing data to a log stored in temporary storage; detecting a property of the received code-tracing data; copying the log to non-volatile storage when the property matches a defined trigger property; and deleting contents of the log according to a caching policy when the property does not match a defined trigger property.

Description:
FIELD OF INVENTION 
       [0001]    The present invention relates to managing code-tracing data. 
       BACKGROUND OF INVENTION 
       [0002]    To improve fault detection in software, software engineers typically add instrumentation code to software components (application software, drivers, and the like) so that code-tracing data is generated automatically by the instrumentation code as the software components execute. The instrumentation code typically generates code-tracing data when certain functions are performed, status changes occur, and the like. A trace manager is used to store the code-tracing data generated by the instrumentation code in a log file. 
         [0003]    If a fault occurs, then the log file can be analyzed to identify the cause of the fault. For example, the code-tracing data may indicate if any unexpected events occurred, or if any expected events did not occur, prior to the fault occurring. 
         [0004]    Although generating and storing code-tracing data has clear advantages, there are also problems associated with managing code-tracing data. 
         [0005]    One problem is that instrumentation code can produce a large amount of code-tracing data every second, which consumes valuable storage space and may slow down the operation of the software as the log file is written to disk. Furthermore, the large quantity of code-tracing data produced makes it difficult to identify the code-tracing data that is relevant to an error. Other errors may be detected that are irrelevant to, and may obscure, the error being targeted. 
         [0006]    It would be advantageous to overcome or mitigate some of these disadvantages, or other disadvantages associated with managing code-tracing data. 
       SUMMARY OF INVENTION 
       [0007]    Accordingly, the invention generally provides methods, systems, apparatus, and software for managing code-tracing data. 
         [0008]    In addition to the Summary of Invention provided above and the subject matter disclosed below in the Detailed Description, the following paragraphs of this section are intended to provide further basis for alternative claim language for possible use during prosecution of this application, if required. If this application is granted, some aspects may relate to claims added during prosecution of this application, other aspects may relate to claims deleted during prosecution, other aspects may relate to subject matter never claimed. Furthermore, the various aspects detailed hereinafter are independent of each other, except where stated otherwise. Any claim corresponding to one aspect should not be construed as incorporating any element or feature of the other aspects unless explicitly stated in that claim. 
         [0009]    According to a first aspect there is provided a method of managing code-tracing data, the method comprises the steps of: 
         [0010]    receiving code-tracing data from an executing software component; 
         [0011]    adding the received code-tracing data to a log stored in temporary storage; 
         [0012]    detecting a property of the received code-tracing data; 
         [0013]    copying the log to non-volatile storage when the property matches a defined trigger property; and 
         [0014]    deleting contents of the log according to a caching policy when the property does not match a defined trigger property. 
         [0015]    The defined trigger property may comprise (i) a defined reference and/or (ii) a defined category. 
         [0016]    The defined reference may identify the software containing the instrumentation code that generated the defined category. 
         [0017]    The defined reference may be associated with a component (such as a service provider, or a driver), an object within a component (such as a framework, device controls, or the like), or code within an object (such as a function or routine). The defined reference may be selected at the desired level of granularity. 
         [0018]    The defined category may be selected from: an error category, a function entry point category, a function exit point category, a general category, an information category, a warning category, an event category, and the like. In some embodiments, it may be desirable to use an error category as the defined category. In some embodiments, it may be desirable for the defined trigger property to consist of an error category, so that copying the log to non-volatile storage will be triggered whenever an error category is created by any instrumentation code. 
         [0019]    The caching policy may be based on a fixed number of bytes stored in the log, so that the earliest code-tracing data is deleted whenever the log reaches the fixed number of bytes. 
         [0020]    The caching policy may be based on time, so that code-tracing data is deleted whenever it is older than a fixed time period, for example, two hours. 
         [0021]    The caching policy may be based on the number of entries stored, so that the earliest code-tracing data is deleted whenever the log reaches the fixed number of entries. 
         [0022]    The caching policy may be based on a combination of some or all of the preceding caching policies. 
         [0023]    The step of deleting contents of the log according to a caching policy when the property does not match a defined trigger property may involve not deleting any contents of the log if the caching policy does not require any contents to be deleted. 
         [0024]    The step of detecting a property of the received code-tracing data and the step of copying the log to non-volatile storage when the property matches a defined trigger property, may be implemented prior to, during, or subsequent to the step of adding the received code-tracing data to the log stored in temporary storage. 
         [0025]    The temporary storage may be computer memory (such as DRAM). 
         [0026]    The non-volatile storage may be one or more magnetic or optical disks. 
         [0027]    The method may be implemented when at least one client (or session) does not request code-tracing data. Alternatively, the method may be implemented even if all clients (all sessions) request code-tracing data. 
         [0028]    The method may further comprise permanently storing code-tracing data in a file for any client (such as a thread in the software component) requesting such storage. This file is separate from the log, and is not subject to the caching policy. 
         [0029]    The step of deleting contents of the log according to a caching policy when the property does not match a defined trigger property may be implemented prior to, during, or subsequent to the step of detecting a property of the received code-tracing data. 
         [0030]    According to a second aspect there is provided a system for managing code-tracing data, the system comprising: 
         [0031]    a trace manager arranged to (i) receive code-tracing data from an executing software component, (ii) add the received code-tracing data to a log, (iii) detect a property of the received code-tracing data, (iv) copy the log to non-volatile storage if the property matches a defined trigger property; and (v) delete contents of the log according to a caching policy. 
         [0032]    The trace manager may comprise a software component. 
         [0033]    The trace manager may be implemented by a CEN XFS compliant software component. Alternatively, the trace manager may be implemented by a proprietary code-tracing data storage component. 
         [0034]    The executing software component that transmits code-tracing data may comprise an XFS service provider. 
         [0035]    According to a third aspect there is provided a computer program comprising program instructions for executing the steps of the first aspect. 
         [0036]    The computer program may be stored on a computer readable medium, such as a computer memory, an input/output data storage device (such as a magnetic or optical disk, or a Flash storage drive) or the like. 
         [0037]    According to a fourth aspect there is provided a computer data signal embodied on a carrier wave encoding instructions that, when executed on a processor, implement the method of the first aspect. 
         [0038]    According to a fifth aspect there is provided a self-service terminal comprising a plurality of modules for providing transaction-related functions to a customer of the self-service terminal, and a controller coupled to the modules, and executing a runtime platform including a trace manager, the trace manager being arranged to (a) receive code-tracing data from an executing software component, (b) add the received code-tracing data to a log stored in volatile storage, (c) detect a property of the received code-tracing data, (d) copy the log to non-volatile storage if the property matches a defined trigger property; and (e) delete contents of the log according to a caching policy. 
         [0039]    According to a sixth aspect there is provided a method of managing code-tracing data, the method comprises the steps of: 
         [0040]    receiving code-tracing data from an executing software component; 
         [0041]    storing the received code-tracing data in a cache as part of a trace log; 
         [0042]    detecting a category of the received code-tracing data; 
         [0043]    copying the trace log to non-volatile storage when the received code-tracing data relates to an error category; and 
         [0044]    deleting the oldest contents of the trace log when a predetermined criterion is satisfied. 
         [0045]    For clarity and simplicity of description, not all combinations of elements provided in the aspects recited above have been set forth expressly. Notwithstanding this, the skilled person will directly and unambiguously recognize that unless it is not technically possible, or it is explicitly stated to the contrary, the consistory clauses referring to one aspect are intended to apply mutatis mutandis as optional features of every other aspect to which those consistory clauses could possibly relate. 
         [0046]    These and other aspects will be apparent from the following specific description, given by way of example, with reference to the accompanying drawings. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0047]      FIG. 1  is a simplified schematic diagram of an SST memory executing software components according to an embodiment of the present invention; and 
           [0048]      FIG. 2  is a simplified schematic diagram illustrating one of the software components (a service provider) executing in the SST memory of  FIG. 1 . 
       
    
    
     DETAILED DESCRIPTION 
       [0049]    Reference will now be made to  FIG. 1 , which is a simplified schematic diagram showing an SST memory  10  executing software components. In this embodiment the SST is an ATM. The software components comprise: a control application  20  and a runtime platform  30 . 
         [0050]    The Control Application  20   
         [0051]    As is known in the art, the control application  20  presents a sequence of screens on an ATM display to a customer at the ATM, collates information from the customer (for example, customer account information from a customer&#39;s ATM card, transaction request, and the like), obtains authorization for a transaction request from a remote authorization host (not shown), and instructs modules within the ATM, as needed, to fulfill an authorized transaction. 
         [0052]    As is also known in the art, the control application  20  also comprises a conventional CEN XFS interface  22  for communicating with a trace manager in the form of an XFS manager (described as box  36  below) in the runtime platform  30 . CEN is the European Committee for Standardisation, and XFS is the eXtensions for Financial Services standard. The current version of this CEN XFS standard is v.3.10. 
         [0053]    It should be appreciated that the XFS manager  36  provides many more functions than merely managing traces. For example, the XFS manager  36  provides services to clients (applications or threads of applications). 
         [0054]    The control application  20  is capable of creating and maintaining multiple sessions, as illustrated by ellipses  26   a,b , n. 
         [0055]    The Runtime Platform  30   
         [0056]    The runtime platform  30  comprises proprietary device drivers,  32   a,b, . . . n  (only three of which are illustrated), an operating system  34 , an XFS manager  36 , and XFS service providers  38   a,b,c,d . . . n.    
         [0057]    In this embodiment, the operating system  34  is a Windows XP (trade mark) operating system, available from Microsoft Corporation (trade mark). The operating system  34  includes a plurality of standard device drivers  40   a,b, . . . n  for interfacing with standard computing devices such as a magnetic disk drive, a display, USB ports, serial ports, a parallel port, and such like. As is well known in the art, the operating system  34  is responsible for memory, process, task, and disk management, and includes routines for implementing these functions. 
         [0058]    The proprietary device drivers  32  are a set of APTRA (trade mark) XFS components, available from NCR Corporation, 3097 Satellite Blvd., Duluth, Ga. 30096, U.S.A. The device drivers  32  provide a range of programming facilities specific to self-service terminal devices and services. 
         [0059]    One function of the device drivers  32  is to enhance the operating system  34  so that the operating system  34  and device drivers  32  together provide high level access to all of the devices and modules, including both standard home computing devices (via the operating system  34 ), and XFS computing devices (via the run-time components  32 ). Thus, the combination of the device drivers  32  and the operating system  34  can be viewed as providing a complete ATM operating system. 
         [0060]    The service providers  38  provide a vendor-independent interface to the device drivers  32 . 
         [0061]    The device drivers  32  interface with self-service specific devices, and include support files (not shown), to allow each device or module to be operated, tested, maintained, and configured. Although only a few device drivers  32   a,b  are shown, there are many device drivers  32 , one for each self-service specific module, such as a card reader (not shown), a receipt printer (not shown), an encrypting keypad (not shown) and FDKs (not shown), and a cash dispenser (not shown). Furthermore, there are many more devices and modules in an ATM than those described herein, for example there are more standard computing devices such as USB ports and a parallel port, there may also be more self-service devices and modules, such as a statement printer, a cash accept module, and the like. These devices and modules are not discussed herein because they are not essential to an understanding of the invention. 
         [0062]    The XFS manager  36  includes an XFS application programming interface (API)  42 , a service provider interface (SPI)  44 , configuration data  46 , and a cache  48 . 
         [0063]    The service providers  38  communicate with the XFS manager  36  and also with the self-service device drivers  32  and the standard device drivers  40  associated with the modules. Suitable service providers are available from NCR Corporation, Satellite Blvd., Duluth, Ga. 30096, U.S.A. 
         [0064]    The service providers  38  provide a high level of abstraction to allow the control application  20  to issue standard XFS commands to request functions and services. The service providers  38  translate these XFS commands for the particular device drivers  32 , 40  used in the runtime platform  30 . Each service provider  38  is typically associated with one module (such as a cash dispenser module). 
         [0065]    Each of the multiple sessions  26  is capable of initiating and maintaining independent communication with the same service provider  38 . 
         [0066]    Reference will now be made to  FIG. 2 , which is a block diagram illustrating one of the service providers  38   a  in more detail. In this embodiment, service provider  38   a  is associated with a cash dispenser. 
         [0067]    The cash dispenser service provider  38   a  comprises a framework portion  60  (which is identical for all of the service providers  38 ), a software development kit (SDK) portion  62  (which is also identical for all service providers  38 ), and a device control portion  64 . The cash dispenser service provider  38   a  is a component (according to the terminology used herein), and the framework portion  60 , SDK portion  62 , and device control portion  64 , are all objects (according to the terminology used herein). As is known in the art, when each of these objects registers with the XFS manager  36 , each object provides the XFS manager  36  with a reference. This reference identifies the object to the XFS manager  36 . 
         [0068]    The framework portion  60  provides the code necessary to handle communications in XFS format. 
         [0069]    The SDK portion  62  provides a set of application programming interfaces (APIs) between the framework portion  60  and the device control portion  64 . The SDK portion  62  ensures that the device control portion  64  is implemented to a specific contract so that the device control portion  64  operates in unison with the framework portion  60 . 
         [0070]    The device control portion  64  is unique for each service provider  38  and includes device driver functionality for the device associated with that service provider  38 . The device control portion  64  also includes function-implementing code  68   a,b,c, . . . n.    
         [0071]    The function-implementing code  68  is illustrated as a plurality of individual boxes. This is merely to illustrate that there is code within the service provider  38   a  providing discrete functions implemented by the cash dispenser. 
         [0072]    The framework portion  60 , the SDK portion  62 , and the device control portion  64  all include instrumentation code  66 , which is illustrated in  FIG. 2  as an ellipse. 
         [0073]    In this embodiment, function-implementing code  68   a  implements a banknote dispense function and function-implementing code  68   b  implements a banknote retract function. 
         [0074]    The instrumentation code  66  provides checkpoints, trace lines, and other diagnosis tools. Whenever one of the functions (for example, the banknote dispense function  68   a ) is called, then a trace line in the instrumentation code  66  for that function creates data to indicate (i) the client thread that called the function, (ii) when the function was called, (iii) the name of the function called, and (iv) the names and values of the parameters input to the function, and output from the function. 
         [0075]    The service provider  38   a  creates a code-tracing object populated with (i) the created data, (ii) the reference identifying the object (for example, the device control portion  64 ) incorporating the trace line in the instrumentation code  66  that created the code-tracing object, and (iii) a category for the created data. 
         [0076]    The reference is included so that the code-tracing object identifies the software that caused the code-tracing object to be created; or more accurately, the software containing the instrumentation code that created the code-tracing object). 
         [0077]    The category indicates what type of data is included in the code-tracing object. For example, the category may be one of the following: entry point, exit point, general data, information, warning, or error. The category is created automatically based on the type of instrumentation code that created the data. 
         [0078]    The category is a property of the code-tracing object. The reference is also a property of the code-tracing object. 
         [0079]    The service provider  38   a  pushes this created code-tracing object (which contains code-tracing data) to the XFS manager  36  using a conventional XFS command (WFMOutputTraceData). 
         [0080]    Each session  26  can request the XFS manager  36  to store the code-tracing data (which is data extracted from the code-tracing object) in a log file using either the WFSSetTraceLevel XFS API call or when a session is opened with the service provider  38   a . This log file is typically stored on permanent I/O storage within the ATM (not shown), such as a disk drive. The configuration information  46  stores the name and path of this log file, which by default is “xfstrace.log”. However, due to the adverse impact in performance caused by saving the code-tracing data in a log file, the sessions  26  may not request the XFS manager  36  to save the code-tracing data. 
         [0081]    In this embodiment, even if the sessions  26  do not request the XFS manager  36  to save the code-tracing data as a log file, the XFS manager  36  saves the code-tracing data to a cache  48  ( FIG. 1 ) within the ATM memory  10 . The code-tracing data that is stored in the cache  48  is referred to herein as buffered data  70 . Since the code-tracing data is being saved to main memory  10  rather than I/O storage, any adverse effect on performance is minimal. 
         [0082]    When the XFS manager  36  stores the code-tracing data to the memory  10 , it detects from the code-tracing object the properties of the code-tracing data, including the reference and the category to which the code-tracing data belongs. 
         [0083]    If one or more of the properties matches a defined trigger property, then the XFS manager  36  transfers the buffered data  70  from memory  10  to I/O storage for subsequent retrieval and analysis. In this embodiment the defined trigger property is that the category is an “error” category, regardless of the value of the reference property. 
         [0084]    To prevent the buffered data  70  from getting too large, the XFS manager  36  implements a caching policy. In this embodiment, the caching policy is based on the number of bytes stored in the memory  10 . The XFS manager  36  does not allow the buffered data  70  to exceed the predefined data size limit. In this embodiment, the predefined data size limit is one megabyte. If the buffered data  70  approaches this limit, then the XFS manager  36  deletes the earliest entries to ensure that this limit is not exceeded. 
         [0085]    The buffered data  70  is separate from, and independent of, any log file (such as “xfstrace.log”) stored in response to a session  26  requesting permanent storage of code-tracing data. 
         [0086]    The service providers  38  are typically able to maintain multiple independent sessions, so that if one session  26   a  requests storage of code-tracing data, but another session  26   b  requests that code-tracing data should not be stored, the XFS manager  36  maintains the buffered data  70  in the cache  48  for code-tracing data relevant to the session  26   b  that does not want permanent storage; and maintains a disk file (such as “xfstrace.log” stored on I/O storage) for code-tracing data relevant to the session  26   a  that does want permanent storage. Since the two sessions  26   a,b  may be performing different functions, different instrumentation code may be executed for each, so the buffered data  70  may be different to the code-tracing data in the “xfstrace.log” file. 
         [0087]    If an error occurs, then the buffered data  70  is written to disk as a file (referred to as the buffer file), and a person can analyze both the xfstrace.log file (for session  26   a ) and the buffered file (for session  26   b ). This is useful because prior art systems would not store the code-tracing data associated with session  26   b , even though the error may have been caused by that session  26   b  rather than the session  26   a  that requested storage of the code-tracing data. 
         [0088]    It will now be appreciated that the above embodiment has the advantage that code-tracing data that would otherwise be discarded is retained, but kept to a manageable size based on deleting the oldest code-tracing data. This ensures minimal impact on performance. Furthermore, if an error occurs, the code-tracing data prior to that error occurring is copied to permanent storage for subsequent analysis so that the most important data is not lost. 
         [0089]    This embodiment ensures that trace information (code-tracing data) leading up to an error in a real-time software component can always be obtained, even if storage of code-tracing data has not been requested. 
         [0090]    Various modifications may be made to the above described embodiment within the scope of the invention, for example, in other embodiments, the SST may not implement the CEN XFS standard. In such embodiments, a proprietary trace manager may be provided. 
         [0091]    In other embodiments, the self-service terminal may be an information kiosk, a financial services centre, a bill payment kiosk, a lottery kiosk, a postal services machine, a check-in and/or check-out terminal such as those used in the retail, hotel, car rental, gaming, healthcare, and airline industries, or the like. 
         [0092]    In other embodiments, different caching policies may be used, based on how long the code-tracing data has been stored, the number of entries stored, a combination of these, or any other convenient policy. Even if the total storage size caching policy is used, the predefined log file size limit may be different to (larger or smaller than) one megabyte. 
         [0093]    In other embodiments, different categories may be used than those described above. A higher or lower number of categories may be used. 
         [0094]    In other embodiments, different properties may be used than those described above. 
         [0095]    A defined trigger property may comprise a sequence of multiple properties, each property linked by a Boolean relationship (such as AND, OR, NOT, and the like) to the other properties in the sequence. 
         [0096]    In other embodiments, a property other than, or properties in addition to, an “error” category may be used as a trigger property. For example, in other embodiments, a defined trigger property may comprise (i) a specific reference (for example, corresponding to the device control portion  64 ) and (ii) an error category, so that storage of the log  70  is only triggered by an error category for object data created by instrumentation code within the device control portion  64 . In other embodiments, there may be a Boolean OR relationship between different properties, so that a trigger occurs if either property is present. 
         [0097]    In the above embodiment, the software components including instrumentation code comprise service providers. In other embodiments, the software components including instrumentation code may comprise applications executing in the environment of an operating system and/or a runtime platform. 
         [0098]    The steps of the methods described herein may be carried out in any suitable order, or simultaneously where appropriate. The methods described herein may be performed by software in machine readable form on a tangible storage medium or as a propagating signal. 
         [0099]    The terms “comprising”, “including”, “incorporating”, and “having” are used herein to recite an open-ended list of one or more elements or steps, not a closed list. When such terms are used, those elements or steps recited in the list are not exclusive of other elements or steps that may be added to the list. 
         [0100]    Unless otherwise indicated by the context, the terms “a” and “an” are used herein to denote at least one of the elements, integers, steps, features, operations, or components mentioned thereafter, but do not exclude additional elements, integers, steps, features, operations, or components.