ACI BASE24 is a market-leading electronic funds transfer (EFT) software application developed by ACI Worldwide. It serves as the transaction processing backbone for global banking.
Running natively on the fault-tolerant HPE NonStop platform (formerly Tandem Computers), it utilizes a modular architecture to acquire, authenticate, route, and authorize financial transactions.
The application modules of ACI BASE24 (spanning Classic and modern BASE24-eps configurations) are categorized in complete detail below:
💳 Channel Acquisition Modules
These front-end modules connect directly to consumer-facing self-service devices and touchpoints to ingest financial messages.
- BASE24-atm: Manages ATM device configurations, handles cash dispenser commands, controls screen displays, and processes terminal commands.
- BASE24-pos: Facilitates electronic data interchange with Point of Sale (POS) merchant terminals, accepting debit, credit, and smart card transactions.
- Stored Value Module (SVM): A localized sub-component within channel management dedicated to the online issuance, balance check, and validation of stored-value gift cards.
🔄 Routing, Switching, & Interfacing Modules
These modules orchestrate the delivery of messages from endpoints to localized authorization hosts or global networks.
- XPNET: The foundational communication middleware module on HPE NonStop that handles network connectivity, balancing transaction routing across regional hosts.
- BIC ISO Interface: Implements standard ISO 8583 payment messaging protocols to communicate directly with major international networks (such as Mastercard or Visa).
- ACI Commerce Gateway: Operates as a secure payment gateway firewall, linking internal HPE NonStop processing routines with public internet channels.
🔐 Security & Authentication Modules
Data integrity modules protect transactions and enforce industry-standard security.
- Transaction Security Services (TSS): Manages PIN verification, encryption/decryption tasks, and hardware security module (HSM) messaging, including native Triple DES (3DES) support.
- Automated Key Distribution System (AKDS): Dynamically updates and automates the distribution of encryption keys directly to field ATMs without manual intervention.
🏦 Business Logic & Authorization Engines
These back-end engines decide whether a transaction flight should be accepted, declined, or deferred.
- Enhanced Authorization Module: Runs customized business logic scripting to evaluate cardholder limits, fraud signals, and stand-in authorization processing.
- Positive Balance File (PBF) Interface: Interfaces with real-time local file structures to check account limits when backend core banking host systems are offline.
📊 Back-Office & Data Management Modules
These modules ensure post-transaction data is accounted for, settled, and audited.
- Interchange Log File (ILF) / Transaction Log File (TLF for ATM, PTLF for POS): Core architectural data constructs that maintain comprehensive records of all ongoing financial messages for balancing and error recovery.
- BASE24-infobase: Provides centralized tools for operational reporting, financial data clearing, settlement processing, and accounting audits.
🛠️ HPE NonStop System Integration Architecture
BASE24 is highly reliable because it integrates with native HPE NonStop mainframe utilities:
- PATHWAY (PATHCOM): Acts as the transaction processing middleware to dynamically load-balance BASE24 server processes across multiple CPUs.
- Enscribe & NonStop SQL/MX: Serves as the native flat-file or relational database layer optimized for low-latency, high-concurrency write operations.
- HPE Shadowbase / AutoTMF: Interacts with the Transaction Monitoring Facility (TMF) to enable active/active dual-site replication, providing instant failover for near-zero transaction downtime.
ACI BASE24 core components on HPE NonStop mainframe platform
Mark Whitfield’s project involvement with ACI Worldwide’s BASE24 / BASE24-eps and XPNET communication middleware is rooted deeply in his tenure at Insider Technologies Limited (ITL) and subsequent senior project management roles. His work primarily spans real-time performance monitoring, transactional tracking, and infrastructure management across HPE NonStop (Tandem) platforms.
His involvement across specific initiatives and client deployments is categorised below:
Product Development & R&D Projects
- BASE24 XPNET Monitoring in Reflex ONE24
- Role: R&D Lead and Software Developer.
- Involvement: Researched and developed specialised software utilities to automatically detect and extract architectural information from XPNET components. He leveraged XPNET EMS (Event Management Service) events and user requests to facilitate real-time monitoring. These components were mapped into graphical drill-down object trees inside the Reflex Status Monitor application.
- XPERT24 (Performance Monitoring & Tracking)
- Role: R&D Lead, Technical Contributor, and Project Manager.
- Involvement: Managed the lifecycle of this NSK-based monitoring tool, which tracks XPNET performance counters including states, traffic rates, and queues across lines, stations, nodes, and processes. The project also involved building mechanisms to track transaction approval and denial metrics over ATM and POS networks.
Client Deployment & Customisation Projects
- HSBC Transaction Monitoring Project
- Role: Technical Lead / Solution Designer.
- Involvement: Designed and executed the implementation of ITL’s RTLX Reactor product on HP NonStop. The project required mapping monitoring solutions into HSBC’s heavily customised payment ecosystem to track ATM and POS transactions governed by BASE24.
- Off-shore Retail Banking Transaction Tracking (Riyadh, Saudi Arabia)
- Role: IT Project Manager (2013).
- Involvement: Managed the delivery of a massive log-parsing project utilizing the BASE24 Classic payment framework. The project safely extracted, relayed, and optimized the parsing of multiple Terabytes of historical ATM and POS transaction logs archived on tapes, moving them into a modern reporting system.
- Global Payments / Standard Chartered Integration Project
- Role: Project Manager / Technical Consultant (2011–2013).
- Involvement: Integrated real-time BASE24 transaction tracking and XPNET capabilities directly into external corporate enterprise frameworks, specifically IBM Tivoli and XPERT24.
- Lloyds Banking Group (LBG) Estate Transformation
- Role: Senior Project Manager.
- Involvement: Led a massive migration strategy that decoupled ATM driving responsibilities away from BASE24 Classic running on HP NonStop platforms, transferring them to Wincor’s ProClassic Enterprise (PC/E) environment.
Mark Whitfield worked on BASE24 / BASE24-eps transaction tracking and XPNET monitoring at Insider Technologies Limited (ITL) in the early part of the millennium. See also HP NonStop Connection Journal article in 2013.
and ITLs RTLX (in 2007)
BASE24-eps & BASE24 XPNET transactions
ACI BASE24 core components on HPE NonStop mainframe platform
PROject Templates 