Category: base24

Mark Whitfield, Senior Project Manager, Career Summary

Mark Whitfield is a UK-based, SC-cleared Senior IT Project Manager and Engagement Manager with over three decades of experience in software development lifecycle (SDLC) delivery.

Mark Whitfield, High-Level Career Summary from 1990 thru 2026

Mark Whitfield, High-Level Career
Summary from 1990 thru 2026

Over his career, he has transitioned from deep technical engineering on legacy systems (HPE NonStop formerly Tandem Computers) to enterprise-scale digital transformation, cloud migrations, and API-led integrations. He is also the author of a comprehensive online toolkit for project delivery frameworks.

Click the ‘Company Worked‘ links below for more detail as required.

Project Management Career Breakdown:

1. Early Engineering & Technical Analysis Era (1990–1995)

  • Company Worked: The Software Partnership / Deluxe Data International
  • Geographical Location: Runcorn (head office) / on-site at both Knutsford / Poole, UK (for Barclays delivery)
  • Clients include: Barclays Bank (BBM II), RaboBank, Bank of Scotland, Girofon, TSB
  • Main Focus Items: Core software design, coding, and back-end integration for electronic desktop banking.
  • Technology Areas: Electronic banking software systems. Periphonics interactive (touch-tone phone) voice software.
  • Software Languages/ Products: sp/ARCHITECT-BANK, SQL, COBOL, SCOBOL, PATHWAY, PATHMAKER, ENSCRIBE, INSPECT, EMS, Tandem Mainframes (now HPE NonStop)
  • Methodology: Early iterative development & structured Waterfall lifecycles.

2. Technical Consultancy & Product Management (1995–2013)

  • Company Worked: Insider Technologies Limited (ITL)
  • Geographical Location: Salford Quays, UK (office); London, UK; Client sites across Europe/ Middle East
  • Clients include: Global Payments, Standard Chartered, Girofon, Rabobank, CRESTCo (Euroclear), Alrajhi Bank, LloydsTSB, HSBC, Santander, Bank of Ireland, Bank of Valletta (Malta) and both Commercial and Piraeus Bank (Greece)
  • Main Focus Items: Infrastructure consulting, volume testing, system management & monitoring, and Service Level Agreement (SLA) monitoring for critical path payment applications. Attending related conferences, EBUG, ITUG, BITUG, SATUG
  • Technology Areas: HPE NonStop monitoring, ATM/POS system & transaction monitoring and stock settlement.
  • Software Languages/ Products: Reflex, RTLX, Sentra, TIVOLI, COMMAND/POST, XPERT24, XPNET, HPE NonStop, HP OpenView Operations, BASE24 Classic, BASE24-eps, C, C++, SQL, SCOBOL, COBOL, TAL, PATHWAY, ENSCRIBE, EMS, MS Project
  • Methodology: Structured Waterfall, Agile Scrum & Custom Product Engineering Lifecycles.
  • Also: Designer and author of a new company website using an Open Content Management framework identified as part of a Research phase.

3. Professional Services Banking Delivery (2013–2014)

  • Company Worked: Wincor Nixdorf
  • Geographical Location: Woking / Bracknell / UK wide
  • Client: Lloyds Banking Group
  • Main Focus Items: Modernising legacy ATM software and directing hardware/software transitions. Implementing ProClassic/Enterprise and PC/E SmartClient (Win 7) to replace the existing ProCash/NDC (Win XP) Stacks on a variety of multivendor devices.
  • Technology Areas: Multi-vendor hardware & software integration for ATMs.
  • Software Languages/ Products: BASE24 Classic, ProClassic Enterprise (PC/E), Oracle, AIX Platform, Windows 7
  • Methodology: Strict PRINCE2 Waterfall and Agile transition methodologies.
  • Also: Wincor ‘Above and Beyond’ award for Customer Satisfaction, Commitment to Excellence and Commitment to One Wincor

4. Digital Sportsbook Transformation (2014–2016)

  • Company Worked: Betfred
  • Geographical Location: Wigan / Greater Manchester, UK
  • Client: Betfred Online and Mobile
  • Supplier Management: for external software suppliers like Degree53, Playtech, Onionsack, Intelligent Payments (Myriad), Inspired, iovation, StreamUK, Finsoft, Ineda, OtherLevels, Appsflyer, Income Access, Activewin, Virgo, Virtue Fusion, In Game Media, Satellite Information Services (SIS) and IGT
  • Main Focus Items: Taking new sports and virtual gaming components live, integrating payment gateways, managing app release cycles, and handling regulatory compliance.
  • Technology Areas: Fraud detection, consumer mobile/desktop betting platforms.
  • Software Languages/ Products: Java, iOS, Android, MS SQL, ASP.NET
  • Methodology: Agile SCRUM.

5. Enterprise Cloud & Integration Delivery (2016–Present)

  • Company Worked: Capgemini UK Consultancy
  • Geographical Location: Manchester / London and UK wide
  • Clients include: Jaguar Land Rover (JLR), Royal Mail Group (RMG), NATS, UK Gov, Heathrow, MuleSoft (augmented)
  • Main Focus Items: Managing hybrid cloud migrations, re-hosting/ refactoring applications, API-led connectivity, and complex manufacturing supply chain data pipelines.
  • Technology Areas: Hybrid cloud infrastructure and system integration.
  • Software Languages/Products: MuleSoft Anypoint Platform, Azure, AWS, Power Platform, Enablon
  • Methodology: Hybrid Agile and PRINCE2.
  • Also: C&CA UK’s Communications & Engagement Award Winner 2022 – Cloud & Custom Applications – Capgemini UK.

In addition to his consultancy work, Mark Whitfield actively publishes his extensive collection of Project Management Templates, which are actively utilized across the industry for RAID Logs, Agile Burndown Charts, and Plan on a Page (POaP) blueprints.

Mark Whitfield HPE NonStop Tandem Experience over three decades

Mark Whitfield is a Senior IT Project Manager with over three decades of experience, heavily rooted in HPE NonStop (formerly Tandem).

His career has transitioned from hands-on NonStop development and product management into large enterprise cloud and digital transformation projects.

Mark Whitfield’s IT project management and software engineering career spans over three decades
Mark Whitfield – Senior IT
Project Manager – SC cleared

His NonStop specific projects and career trajectory can be broken down (at a high-level) by era, location, and focus as follows:

1990–1995: Early Programming

  • Location: Barclays, Poole, Dorset, UK
  • Focus: Electronic banking programming and development on Tandem Mainframe Computers.
  • Projects: Wrote, developed, and maintained software like sp/ARCHITECT-BANK and associated billing software (in Poole, 1993). This involved building early electronic banking systems for desktops long before internet banking was prevalent.
1993, Barclays, Poole, Dorset, UK
1993, Barclays, Poole, Dorset, UK

1995–2013: Senior Development & Product Management

  • Location: Insider Technologies, Salford Quays, Manchester, UK
  • Focus: NonStop product management, software design, and real-time event monitoring.
  • Projects: Product managed software lifecycles for four monitoring products (two NonStop based). This included creating health and diagnostic tools (RTLX, Reflex 80:20, Reflex ONE24, XPERT24) for mission-critical NonStop environments. He also deployed volume testing on early HP NonStop S7000 nodes for CRESTCo in London in 1997.
Spinnaker Court, Chandlers Point, Insider Technologies, Salford Quays, Manchester, UK
Insider Technologies, Salford Quays, Manchester, UK

2013–2014: Legacy Migration & Consulting

  • Location: Wincor Nixdorf & ATM/POS Financial Services, UK
  • Focus: Modernization and migration of legacy systems.
  • Projects: Managed a £5M+ replacement of legacy HP NonStop software systems at a large UK retail bank, migrating functionalities to AIX-based J2EE and Oracle architectures.
Diebold Nixdorf Ltd, Cain Rd, Binfield, Bracknell, RG12 1WP
Diebold Nixdorf Ltd, Cain Rd,
Binfield, Bracknell, RG12 1WP

2016–Present: Cloud Transformation & Digital Delivery

  • Location: Capgemini UK, Trafford Quays / UK-Wide
  • Focus: Delivery of enterprise-scale middleware, digital transformation, and cloud.
  • Projects: Acts as an Engagement Manager and SC-Cleared Project Manager. Focus includes Agile software delivery for Air Traffic organisations (e.g., iOS applications for military and public-facing airspace tracking) and rolling out middleware solutions.
Capgemini UK, Floor 7, Venus Building, Trafford Quays, Manchester. M41 7HA
Capgemini UK, Floor 7,
Venus Building, Trafford Quays
C&CA UK's Communications & Engagement Award Winner 2022 - Cloud & Custom Applications - Capgemini UK
C&CA UK’s Communications & Engagement Award Winner 2022 – Cloud & Custom Applications – Capgemini UK

For more career detail, click here.

ACI BASE24 core components on HPE NonStop mainframe platform

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.

BASE24 Electronic Funds Transfer (EFT) software application developed by ACI Worldwide, Overview
BASE24 Electronic Funds Transfer (EFT) software application developed by ACI Worldwide, Overview

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.

🏦 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

2. BASE24 Electronic Funds Transfer (EFT) software application developed by ACI Worldwide, Overview
BASE24 Electronic Funds Transfer (EFT) software application developed by ACI Worldwide, Overview

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.

BASE24-eps extraction and ITLs RTLX in 2007
BASE24-eps extraction
and ITLs RTLX (in 2007)
RTLX Reactor (in 2012) for tracking BASE24-eps and BASE24 XPNET transactions
RTLX Reactor (in 2012) for tracking
BASE24-eps & BASE24 XPNET transactions

ACI BASE24 core components on HPE NonStop mainframe platform

Overview of BASE24 and XPNET plus application timeline by era

Overview of BASE24 and XPNET

BASE24 is an enterprise-grade electronic funds transfer (EFT) software suite developed by Applied Communications Inc. (now ACI Worldwide). It handles real-time transaction acquiring, authenticating, routing, switching, and authorization across ATMs, Point-of-Sale (POS) networks, and digital payment channels.

XPNET (Exchange Protocol Network) is the fundamental communications middleware layer designed explicitly for BASE24 on fault-tolerant systems. It acts as an abstraction layer managing interprocess communications (IPC), network protocols (e.g., Bisync, X.25, TCP/IP), line management, device messaging, and high-volume transaction routing. Together, they form the transactional backbone for a majority of the world’s top financial institutions.

I 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.

BASE24-eps extraction and ITLs RTLX in 2007
BASE24-eps extraction
and ITLs RTLX (in 2007)
RTLX Reactor (in 2012) for tracking BASE24-eps and BASE24 XPNET transactions
RTLX Reactor (in 2012) for tracking
BASE24-eps & BASE24 XPNET transactions

Deep-Dive Architecture and Technology Stack

1. BASE24 Core Design

  • Process Pair Architecture: Designed natively around Tandem’s process pairs. A Primary Process performs the active transaction switching while a Backup Process remains synchronized in a standby state. If the hardware or primary process fails, the backup takes over instantly with zero data loss or session drops.
  • Functional Modules: Divided into specific transactional entities:
    • ATM (Automated Teller Machine Device Handler): Direct control and state management of physical terminals using custom message streams (e.g., Diebold, NCR).
    • POS (Point of Sale): Merchant terminal management and merchant accounting integration.
    • Auth (Authorization Processor): Internal validation scripts against account records or stand-in limits.

2. XPNET Middleware Engine

  • Line and Station Infrastructure: XPNET maps communication through abstract configurations. A Line represents a physical or logical network pipe, and a Station represents an endpoint (e.g., an interchange gateway or terminal node).
  • Dynamic Load Buffering: Employs internal memory queue structures to absorb traffic spikes from international card networks (such as Visa and Mastercard) without spilling into disk storage.
  • Protocol Multi-threading: It decouples low-level link dynamics (e.g., CRC checking, dropouts) from core business logic, converting legacy and modern network formats into standardized internal transaction tokens.

Application Development Timeline & Political Breakdown

The timeline below details how geopolitical, regulatory, and corporate ownership developments directly shaped versioning and core code changes in BASE24 and XPNET.

Era 1: The Tandem & Expansionist Era (1975–1992)

  • Geopolitical & Industry Context: The rise of consumer credit card networks, personal checking accounts, and the physical expansion of banking via ATMs. Regional networks were fragmented, necessitating specialized software to cross-connect them.
  • Corporate Dynamics: Applied Communications Inc. (ACI) operated as an independent software house in Omaha, Nebraska, forming a deep partnership with Tandem Computers before being acquired by US West (1988) and later Tandem directly (1991).
  • Year-by-Year Code & Technical Milestones:
    • 1975–1981: Initial exploration of high-availability banking systems on Tandem NonStop computers. Developers laid the groundwork using Tandem Screen COBOL and low-level communication drivers.
    • 1982: BASE24 v1.0 officially launches. The original codebase was written in TAL (Tandem Application Language), a high-performance, structured system programming language designed specifically for NonStop systems.
    • 1985: A primitive version of XPNET is spun out from early shared-memory messaging code to support multi-protocol lines (Bisync, Async) without forcing restarts of the core application.
    • 1987: Introduction of early ISO 8583 message formatting engines within the core routing code. This allowed the software to natively interpret standard financial messaging frames across distinct interbank networks.
    • 1991: Tandem acquires ACI. Code refactoring focused heavily on optimizing interactions with Tandem’s native file system (Enscribe) and expanding the XPNET process memory layout to take advantage of new Tandem CLX architecture performance.

Era 2: The TSA Corporate & Public Market Era (1993–2000)

  • Geopolitical & Industry Context: Globalization of financial services, the consolidation of national card switches, and the commercial explosion of internet banking and POS devices.
  • Corporate Dynamics: Tandem divested ACI to a private holding company, leading to the creation of Transaction Systems Architects (TSA) in late 1993. TSA went public on NASDAQ in 1995, pushing development velocity to meet Wall Street expectations.
  • Year-by-Year Code & Technical Milestones:
    • 1993–1994: Standardized compilation routines moved to Tandem’s pTAL (portable TAL) to bridge code execution compatibility between older CISC-based architectures and the newly emerging MIPS RISC processors.
    • 1995–1996: BASE24 version 4.x introduces advanced multi-institution handling inside a single logical codebase, allowing multi-tenant processing for third-party credit card consolidators.
    • 1997: Release of BASE24 v5.x, featuring significant expansions in XPNET (v2.x) to accommodate native TCP/IP sockets alongside aging X.25 line infrastructures.
    • 1998–1999: Heavy investment into Y2K compliance remediation. Code changes involved updating binary-coded decimal (BCD) date configurations, expanding date-storage windows across Enscribe files, and deploying the BASE24 Year 2000 System Assessment frameworks globally.

Era 3: Enterprise Platform Shift & Consolidation (2001–2014)

  • Geopolitical & Industry Context: Post-9/11 regulatory changes (e.g., USA PATRIOT Act), the implementation of modern security standards like Triple DES (TDES), and the birth of the PCI-DSS (Payment Card Industry Data Security Standard). Mainframes and alternative hardware processors (IBM, HP-UX) became fierce competitors to Tandem.
  • Corporate Dynamics: TSA officially rebranded to ACI Worldwide, Inc. (ACIW) in 2007. A strategic decision was made to rewrite the platform to break vendor lock-in and provide cross-platform flexibility.
  • Year-by-Year Code & Technical Milestones:
    • 2001–2002: Standard cryptographic layers within BASE24 are systematically modified to enforce Triple DES compliance across automated teller machines.
    • 2003: ACI introduces BASE24-eps (Enterprise Payments System). This marked a foundational architecture shift, moving away from TAL/pTAL entirely to an object-oriented paradigm written in C++ and designed to execute cross-platform (HPE NonStop, IBM z/OS, AIX, Linux).
    • 2005–2006: BASE24-es/eps code integrates with enterprise middleware layers such as IBM WebSphere MQ, using CICS containers on z/OS to deliver modern service-oriented architecture (SOA) web services wrappers.
    • 2008–2010: ACI shocks the banking industry by announcing the sunsetting of standard maintenance for classic Tandem NonStop BASE24 by late 2011. Millions of lines of legacy TAL code are effectively frozen, forcing major migrations toward BASE24-eps.
    • 2011–2013: Code enhancements center around PA-DSS validation and securing encryption pathways to ensure tokenized processing. XPNET 3.x is deployed onto newer HP Integrity Itanium-based J-Series and H-Series blades.

Era 4: Modernization, Cloud-Native, and Open Systems (2015–Present)

  • Geopolitical & Industry Context: The dominance of Real-Time Payments (RTP, FedNow, ISO 20022 formats), cloud computing mandates, and aggressive cost-reduction pushes away from high-maintenance legacy hardware configurations.
  • Corporate Dynamics: ACI pivots sharply to open-ecosystem SaaS delivery, cloud partnerships (AWS, Microsoft Azure, Google Cloud), and co-development with IBM to optimize cross-platform throughput.
  • Year-by-Year Code & Technical Milestones:
    • 2015–2016: BASE24-eps code is successfully ported to Red Hat Enterprise Linux (RHEL) on standard x86 processors. This architectural pivot offered a reduction in total cost of ownership (TCO) compared to legacy hardware by providing massive processing scaling.
    • 2018–2020: The introduction of standard ISO 20022 messaging libraries into the switching matrix to support instant transaction settlement schemes globally.
    • 2021–2024: Legacy middleware systems are phased down. Modern releases feature direct REST API hooks, cloud-adaptor hooks, containerised microservices integration, and extended configuration capabilities via the ACI Desktop GUI.
    • 2025–2026: ACI partners with IBM to launch native 64-bit deployment optimizations for BASE24-eps running on IBM Z mainframes (including z16/z17 configurations), incorporating hardware-driven AI fraud analysis models and full PCI-SSF (PCI 4.0) certification.

Overview of BASE24 and XPNET plus application timeline by era

BASE24 Electronic Funds Transfer (EFT) software application developed by ACI Worldwide, Overview

BASE24 is a market-leading, fault-tolerant Electronic Funds Transfer (EFT) software application developed by ACI Worldwide. For decades, it has served as the backbone for global banking, processing billions of ATM, Point of Sale (POS), and smart card transactions.

BASE24 Electronic Funds Transfer (EFT) software application developed by ACI Worldwide, Overview
BASE24 Electronic Funds Transfer (EFT) software application developed by ACI Worldwide, Overview

The product achieves its landmark 24/7/365 uptime by running natively on the HPE NonStop architecture—originally engineered by Tandem Computers.

1. Underlying Technology Stack

BASE24 Classic was built from the ground up to utilize the unique properties of the Tandem/HPE NonStop platform:

  • Operating System: HPE NonStop Kernel (NSK) / Guardian.
  • Database: Enscribe, a native hierarchical/flat file database optimized for ultra-fast, unstructured file access. Newer iterations use NonStop SQL/MX.
  • Programming Languages: Primarily TAL (Tandem Application Language), pTAL, and COBOL/SCOBOL.
  • Middleware: PATHWAY (PATHCOM), which acts as the transaction processing monitor to dynamically manage and load-balance server processes.

2. High-Level Component Architecture

BASE24 relies on an interconnected network of specialized processes that route and manage messages.

A. XPNET (The Networking Engine)

XPNET is a critical, proprietary communication subsystem. It provides the messaging infrastructure where applications interface with network communication lines. XPNET acts as the buffer layer, monitoring physical lines, enforcing transaction timing checks, and distributing data loads uniformly across CPUs.

B. Device Handlers (DH)

Device Handlers act as the translators for peripheral devices.

  • Function: They intercept hardware-specific protocol messages (e.g., Diebold or NCR formats from ATMs) and normalize them into BASE24’s internal standard message format.
  • Security: DH processes handle terminal-level PIN encryption, coordinate MAC (Message Authentication Code) keys, and initiate terminal downline loads.

C. Authorization Process (AUTH)

AUTH is the core decision engine of the application.

  • Function: It validates card restrictions, tracks card usage accumulations, and performs transaction risk checks.
  • Fallback Management: If a bank’s core system goes offline, AUTH drops into “Stand-Alone” or “Negative/Parametric Authorization” mode, approving transactions locally up to safe, pre-defined limits.

D. Host Interfaces (HI)

The Host Interface connects BASE24 to the financial institution’s primary backend core banking systems. It handles “On-Us” transactions—meaning the card used belongs to the bank owning the terminal.

E. Interchange Interfaces (II)

The Interchange Interface formats, translates, and routes transactions to global credit/debit networks (such as Visa, Mastercard, AMEX) or regional switches. It transforms internal BASE24 data formats into compliance standard formatting, such as ISO 8583. It handles “Not-On-Us” transactions.

3. Core Database & File Structure

BASE24 captures system activities across specialized transactional and tracking files, mostly utilizing Enscribe:

  • TLF (Transaction Log File): The primary log capturing every ATM event, amount, response code, and terminal ID in real-time.
  • PTLF (POS Transaction Log File): Mirrors the utility of the TLF, but optimizes records strictly for merchant POS transactions.
  • LCONF (Logical Network Configuration File): Dictates how network configurations, devices, institutions, and communication paths map into XPNET.
  • CAF (Cardholder Authorization File): Stores specific card numbers, limits, and statuses used for stand-alone authorization if host links break down.

4. Daily Operational Processes

Beyond live message switching, BASE24 executes several critical back-office operations:

  • Extract: Periodically filters transaction data from live TLF/PTLF logs to move to external billing arrays.
  • Refresh: Downloads updated data dumps (such as blacklisted cards or updated balances) from core hosts into local BASE24 database files.
  • Settlement Initiator: Aggregates transaction volumes at specified cutoff times to reconcile balanced records between ATMs, POS terminals, and clearing networks.

5. Why Tandem/HPE NonStop is Essential to BASE24

BASE24 relies on the hardware/software synergy provided by HPE NonStop to achieve near-zero downtime:

  • Shared-Nothing Architecture: Processors operate independently with their own memory stacks. If a physical CPU suffers hardware failure, it cannot corrupt the rest of the application.
  • Process Pairs: BASE24 components operate via a primary process in one CPU and a backup process in an alternate CPU. The primary constantly syncs checkpoint data with its backup. If the primary drops, the backup assumes processing instantly without interrupting transaction flights.
  • Active/Active Configuration: Utilizing replication software like HPE Shadowbase or DRNet, financial firms link distinct geographic NonStop locations. Both processing sites operate concurrently, managing localized transactions and replicating states reciprocally.

6. Product Evolution: BASE24 Classic vs. BASE24-eps

ACI Worldwide evolved the platform from BASE24 Classic into BASE24-eps (Enterprise Payment System):

Product Evolution: BASE24 Classic vs. BASE24-eps
Product Evolution: BASE24 Classic vs. BASE24-eps

BASE24 Electronic Funds Transfer (EFT) software application developed by ACI Worldwide, Overview

2. BASE24 Electronic Funds Transfer (EFT) software application developed by ACI Worldwide, Overview
BASE24 Electronic Funds Transfer (EFT) software application developed by ACI Worldwide, Overview

eBUG (European BASE24 User Group) Conference Overview and Chronological  Timeline

The eBUG (European BASE24 User Group) Conference is the premier annual gathering for financial institutions, retail banking professionals, and technical architects utilizing ⁠ACI Worldwide’s foundational retail payment engine, BASE24 and BASE24-eps.

Operating alongside global HPE NonStop hardware environments, the conference traditionally functions as a collaborative technical focus group (TFG) and customer roundtable. It brings together industry experts to address mission-critical transaction switching, regulatory compliance mandates, payment security architectures, and core software migrations.

Detailed Era Breakdown & Timeline

Era 1: The Classic BASE24 & ITUG Tandem Era (1980s – Late 1990s)

Focus: Evolution of core ATM/POS switching on Tandem (HPE NonStop) platforms, localized compliance, and basic card processing networks.

  • 1982–1985: The birth of the early European user networks following the launch of BASE24 software by Applied Communications Inc. (now ACI Worldwide). Early meetings are heavily dependent on regional vendor user group support.
  • 1992: Initial formations of explicit regional sub-committees under the International Tandem User Group (ITUG). The European base of users establishes formal communication pipelines.
  • 1996: Increased focus on the early adoption of regional card mandates, standardising early transaction switching over X.25 networks, and prepping mainframe systems for high-availability roundups.
  • 1999: A definitive milestone focused on Y2K compliance readiness. Conferences during this era are heavily centered on stress-testing legacy BASE24 code blocks, ensuring clock dates rollover flawlessly across financial networks without disrupting global merchant processing.

Era 2: The EMV Mandate & “Classic-to-EPS” Transition Era (2000 – 2010)

Focus: Overhauling core code for Chip & PIN (EMV) regulations, migrating toward open system frameworks, and introducing the next-generation BASE24-eps payment platform.

  • 2003: The EMV Blueprint Era. The conference takes a primary steering role for European banks facing strict Eurocard, Mastercard, and Visa (EMV) liabilities. User sessions heavily focus on updating terminal messaging scripts.
  • 2005: Introduction of BASE24-eps to the wider user group community. Discussions shift away from the classic architecture toward modern open-systems deployments, leveraging UNIX, Linux, and IBM z/OS alongside traditional NonStop environments.
  • 2007 (Istanbul, Turkey): The group expands geographic footprints into the borders of Europe and Asia. Themes heavily stress global interoperability, cross-border transactional routing, and real-time fraud monitoring.
  • 2008 (Vienna, Austria): High-water mark for attendance during the mid-2000s. Presentations focus on deep-dive technical configurations of BASE24-eps Release 08.2, service-oriented architecture (SOA) wrappers, and high-availability testing matrices.
  • 2009 (Prague, Czech Republic): Real-time monitoring tools become a central talking point. Despite global financial pressures, the user community explicitly defends the strength of ⁠HPE NonStop infrastructure for running foundational retail networks.

Era 3: Security Hardening & The Independent Pivot Era (2011 – 2018)

Focus: Adapting payment loops to rigid PCI-DSS requirements, cloud capability tracking, and shifting the conference structure to independent consulting sponsorships.

  • 2011: Focus turns squarely onto PCI-DSS Compliance and tokenisation. Roundtables detail architectural techniques to secure transaction journals, encrypt key lines, and prevent man-in-the-middle exploits at the ATM level.
  • 2012 (London, UK): Held at the historic ⁠Trinity House near Tower Bridge, this event marks a structural pivot. Moving away from a pure ACI-hosted workspace, independent payment consultancies (such as PayX) drive user discussions. This Technical Focus Group explicitly evaluates the limits of legacy systems against “intelligent” multi-vendor ATM software.
  • 2015: Immediate focus addresses the challenges of Real-Time / Instant Payments mandates across the Eurozone. Systems engineers share optimization scripting paradigms to support sub-second processing SLA ceilings.
  • 2018: The rise of Open Banking / PSD2 Regulations. Technical breakout sessions outline how to safely open classic BASE24 architectures to third-party APIs through microservices wrappers and middleware adapters without breaking strict system uptime criteria.

Era 4: Modernisation & Cloud-Native Coexistence Era (2019 – Present)

Focus: ISO 20022 message standard migrations, cloud-native deployments, and containerization strategies.

  • 2020–2022: Transition to hybrid tracking methodologies due to travel constraints. The baseline focus targets data integration, remote system management, and virtualized system-hardening techniques.
  • 2023–2024: The ISO 20022 Mandate. Sessions are dominated by the industry-wide migration from legacy ISO 8583 message lines to the XML-based ISO 20022 financial standard. Systems architects present automated script parsers to translate real-time payment formats across legacy logic systems.
  • 2025–2026: Integration of ⁠Cloud-Native BASE24-eps architectures. Contemporary meetups explore containerized execution patterns, utilizing AI models within the authorization loop to spot edge-case fraud patterns in real-time, and evaluating long-term roadmaps for hardware-security modules (HSMs).

eBUG (European BASE24 User Group) Conference Overview and Chronological  Timeline

Connect – HPE NonStop Technology & Business Conference, Nonstop TBC, 2026

The HPE NonStop Technology & Business Conference (Nonstop TBC 2026)—hosted by Connect Worldwide—will take place from September 14 to September 17, 2026, at The Rosen Plaza in Orlando, Florida.

The HPE NonStop Technology & Business Conference (Nonstop TBC 2026)—hosted by Connect Worldwide—will take place from September 14 to September 17, 2026, at The Rosen Plaza in Orlando, Florida
Connect – HPE NonStop Technology &
Business Conference (Nonstop TBC 2026)

This signature annual event brings together enterprise IT leaders, software engineers, and solution architects to explore innovations shaping mission-critical environments.

Core Event Schedule

The four-day conference partitions its educational and collaborative tracks as follows:

  • September 14: Dedicated exclusively to HPE Education Day, featuring expanded deep-dive technical pre-conference courses.
  • September 15–17: The primary conference technical program and breakout sessions.

Key Focus Areas & Tracks

The 2026 event focuses heavily on bridging mission-critical legacy stability with modern software frameworks:

  • AI-Driven Transformation: Adapting continuous availability to the demands of modern artificial intelligence and machine learning workloads.
  • Digital Resilience & Security: Mitigating modern risks, modernising backup systems, and maintaining absolute runtime security.
  • FinTech & Payments: Real-world operational strategies from global peers managing transaction-heavy workloads.
  • Expanded Business Track: New for 2026, this track aligns executive business drivers with technical architectures for practical IT roadmap building.

Logistics and Pricing

  • Venue: The Rosen Plaza Hotel, situated at 9700 International Drive, Orlando, Florida.
  • Pricing: A newly reduced Early Bird Registration ticket is available for $895.
  • Accommodations: Registered attendees gain access to a dedicated Connect block rate of $181 per night (including tax).
  • Sponsorships: Major industry partners, such as comforte, sponsor the event, granting enterprise buyers direct visibility into third-party NonStop infrastructure add-ons.

Connect Worldwide – HPE NonStop Technology & Business Conference, Nonstop TBC, 2026

HPE NonStop architecture (Tandem Computers) by Era and Year

Mark Whitfield invested many years in the HPE NonStop field from 1990. The HPE NonStop architecture (originally Tandem Computers) is a legendary fault-tolerant system known for 100% continuous availability. The platform’s hardware and software execution evolved across six distinct eras and processor transitions:

1. The Tandem Founding Era (1976–1981)

  • Years: 1976–1981
  • Processors: Proprietary 16-bit stack processors (e.g., Tandem/16, NonStop II)
  • Architecture: The foundational “shared-nothing” parallel architecture. Featured redundant components (processors, disks, power supplies) connected by a proprietary dual-bus (Dynabus). The operating system provided instant automated failover.

2. The Cyclone & Early RISC Era (1981–1996)

  • Years: 1981–1996
  • Processors: Proprietary non-RISC (NonStop Cyclone) & MIPS R-series RISC
  • Architecture: Expanded into 32-bit computing. To keep pace with industry performance, Tandem transitioned from proprietary processors to off-the-shelf MIPS RISC processors while heavily emulating the original instruction set for compatibility.

3. The Himalaya/ServerNet Era (1997–2004)

  • Years: 1997–2004
  • Processors: MIPS R-series
  • Architecture: Replaced the legacy Dynabus with ServerNet, a high-speed system interconnect that served as an early precursor to modern networking fabrics. (Compaq acquired Tandem in 1997, which subsequently merged with HP in 2002).

4. The Integrity Itanium Era (2005–2013)

  • Years: 2005–2013
  • Processors: Intel Itanium (TNS/E)
  • Architecture: Branded as HP Integrity NonStop (NonStop i). The platform moved off proprietary silicon to standard Intel Itanium processors. This was driven by the “NonStop Advanced Architecture” (NSAA), lowering hardware costs while maintaining Availability Level 4 (AL4) standards.

5. The NonStop X (x86-64) Era (2014–Present)

  • Years: 2014–2026
  • Processors: Intel Xeon x86-64 (TNS/X)
  • Architecture: Fully decoupled the OS from proprietary hardware by shifting to standard Intel x86-64 processors and InfiniBand fabric. The latest compute nodes (such as the NS5 X5 and NS9 X5) utilize modern Intel Xeon Scalable processors to maintain maximum Availability Level 4 (AL4) workloads.

6. The Virtualized NonStop Era (Present)

  • Years: 2015–Present
  • Processors: Virtual Machines / Cloud / x86
  • Architecture: HPE extended the platform to support Virtualized NonStop Software, allowing fault-tolerant enterprise workloads to run entirely in private clouds via standard VMware or hybrid architectures, independent of specific physical servers.
Globally published HP NonStop journal – ‘The Connection’
HPE NonStop article by Mark Whitfield in 2013, working for Insider Technologies Limited in Salford Quays

BASE24 and BASE24-eps architecture overview

The BASE24 electronic payment system developed by ACI Worldwide exists in two primary architectural generations:

BASE24 Classic (historically deployed on HPE NonStop / Tandem fault-tolerant hardware) and

BASE24-eps (Enterprise Payments System, built using an object-oriented C++ framework deployable across open systems, z/OS, and cloud infrastructure).

Despite structural differences, both share a highly optimized, component-based transaction routing engine.

BASE24 and BASE24-eps architecture overview
BASE24 architecture overview

Core Structural Component Layers

The component architecture maps the complete end-to-end lifecycle of a financial message (such as ISO 8583) through five distinct functional sub-systems:

1. Network & Message Routing Component (XPNET)

  • Purpose: Coordinates all message traffic across internal processes and physical network nodes.
  • Function: Operates as a specialized middleware network manager that decouples low-level communication links from upper transaction routing layers.
  • Configuration: Relies on a Logical Network Configuration File (LCONF) to define active execution nodes, hardware lines, and physical stations.

2. Perimeter Access Layer (Device Handlers)

  • Purpose: Translates device-specific message protocol formats into the system’s unified internal format.
  • ATM Device Handlers (ATMDH): Manage direct connectivity to automated teller machines, unpack specific vendor dialects (such as Diebold or NCR states), and track terminal hardware statuses.
  • POS Device Handlers (POSDH): Interface with point-of-sale acquirer terminals and merchants.
  • Security Operations: Triggers immediate payload encryption/decryption and Hardware Security Module (HSM) PIN-block translation directly within this ingestion ring.

3. Core Transaction Logic (Authorization System)

  • Purpose: Determines whether a payment request should be accepted, rejected, or modified.
  • Full On-Us Authorization: Inspects internal databases for matching account records, positive balances, and velocity thresholds to issue real-time decisions.
  • Parametric/Negative Checks: Validates card status against offline negative files, usage restrictions, or custom risk parameters.
  • Scripting Engine: Modern BASE24-eps variants execute localized transaction routing scripts via customized operators without forcing a compile rewrite of the core engine core.

4. Boundary Channels (Interchange & Host Interfaces)

  • Interchange Interfaces (ICH): Package and transform the transaction payload into international network profiles (e.g., Visa, Mastercard, regional switches). It handles strict message mapping and regional network check requirements.
  • Host Interfaces (HIF): Create synchronous links back to an institution’s underlying Core Banking system to apply ledger adjustments, check balances, or execute real-time holds.

5. Offline & Administrative Subsystems

  • Extract Component: Gathers active transaction logs and streams filtered payloads out to analytical reporting databases.
  • Refresh Component: Updates terminal operational data, key packages, and card exclusion lists from parent systems down to active execution nodes.
  • Settlement Initiator: Groups, cleanses, and batches net-clearing totals to finalize payment entries into regional clearinghouses.

Architectural Divergence: Classic vs. EPS

The structural design varies significantly depending on the generation of the software deployment:

BASE24 and BASE24-eps architecture overview
BASE24 and BASE24-eps architecture overview

End-to-End Component Transaction Flow

  1. An ATM transaction arrives at the network interface layer managed by XPNET.
  2. The message is routed to the Device Handler, which strips hardware packaging and requests translation from the HSM.
  3. The clean internal message passes to the Authorization Engine.
  4. If it is a “Not-On-Us” card, the engine identifies the destination BIN and transfers routing control to the Interchange Interface.
  5. The Interchange Interface maps the payload to the external scheme standard (such as Visa) and transmits it to the external network.
  6. The outbound network response is unwrapped by the Interchange component and tracked through the core engine to log final response codes.
  7. The transaction safely records inside the active log file, allowing the Extract / Settlement components to pick it up later during batch processing.

BASE24 and BASE24-eps architecture overview

BASE24 and BASE24-eps architecture overview
BASE24 and BASE24-eps architecture overview