In 1984, three students from the Danish Technical University created a PC-based accounting system called PCPLUS. This is the beginning of the Business Central story. I have been given access, by Microsoft (Thanks!!) to the historic source code for these products and this is the first episode in the Business Central history series, enjoy:
Here is the cool into animation as a GIF 🙂
In this inaugural episode of “The History of Business Central” series, Erik takes us all the way back to the very beginning — before Navision, before NAV, before Business Central. This is the story of PC Plus, a single-user accounting system created in Denmark in the early 1980s that would ultimately become the ancestor of what we know today as Microsoft Dynamics 365 Business Central.
The Origins: Three Engineers and a Vision
PC Plus was created by three founders — Jesper, Peter, and Torben — straight out of engineering school. While Erik notes some conflicting sources on exact dates, development appears to have started around 1983, with products announced in 1984 and availability around 1985. The company behind the software was called PC&C (sometimes written as PCSC).
At this point in its history, PC Plus was a single-user accounting system running on the IBM PC platform. To understand why it was remarkable, you need to understand the hardware and software landscape of the time.
Setting the Scene: Computing in the Mid-1980s
The software of this era ran on machines like the IBM 5150 PC, powered by an Intel 8088 CPU running at 4.77 MHz. Everything Erik demonstrates in the video runs at the actual speed these programs would have operated at — which is to say, slowly by modern standards.
The IBM PC had launched in 1981 and quickly gained popularity. The XT came out a few years later, and by the mid-80s the 286 was just starting to emerge. This was the hardware foundation that all the accounting software of the era had to work within.
The Competition: DAC Easy Accounting
To appreciate what PC Plus achieved, Erik first demonstrates DAC Easy Accounting (the 1987 version), which had won the 1986 PC World “World Class Award” and the 1985 InfoWorld Product of the Year. This was supposedly the cream of the crop in accounting software.
The experience was, to put it mildly, painful:
- Screen updates were visibly slow
- Navigation relied entirely on numbered menu selections
- When entering journal transactions, you had to know account numbers by heart — there was no lookup functionality
- Pressing Escape was “not allowed” in certain fields, leaving users trapped
- After posting a transaction, the data simply disappeared with no confirmation or on-screen review
- The only way to see your posted data was to print it on paper
As Erik summarized: “This is an awful experience.”
PC Plus: A Quantum Leap in Usability
In stark contrast, PC Plus demonstrated a level of polish and user-friendliness that was far ahead of its time. Even the startup sequence was notable — the company name “PC&C” animated on screen, with the “PC” transforming into part of the product name “PC Plus.”
Main Menu and Company Management
The main menu offered clear options: use a company, create a company, make a backup, restore a backup, and delete a company. Users could select between multiple companies — a feature that would remain a hallmark of the product line through to Business Central.
Module Structure
The application was organized into modules that will look familiar to anyone who has worked with Navision or Business Central:
- Finance — General ledger
- AR — Customers (accounts receivable)
- AP — Vendors (accounts payable)
- Inventory
- General — Company information, accounting periods, VAT settings, and groups
Licensing Model
PC Plus used a license key system. You would buy access to the system and receive secret keys matched to your serial number. Entering these keys would unlock different pieces of the software — a concept that persisted in various forms throughout the product’s evolution.
Innovative Features
Several features set PC Plus apart from the competition:
- Built-in calculator (F9) — Available everywhere in the system. Erik notes that the story goes this was inspired by American software (possibly Borland’s SideKick or similar utilities). The founders decided that no matter where you were in the system, a calculator should be accessible.
- Report designer — A free-form report designer where you could specify X and Y coordinates for each field on the report. While it might seem primitive by today’s standards, in 1985 this was remarkable.
- Batch printing — Users could queue up multiple reports (balance sheets, KPI reports, etc.) and print them all at once. Given that matrix (dot-matrix) printers could take a very long time, being able to say “print everything” and then go to lunch was a significant convenience.
- Context-sensitive help (F1) — Pressing F1 showed which function keys were available in the current context. Pressing F1 again opened the built-in manual, complete with page navigation.
- Data exchange — The system supported data exchange with Lotus 1-2-3 and the Lotus framework, allowing users to import and export data in different formats.
The F-Key Layout
An interesting detail: the help screen displayed function keys in two columns. This matched the physical layout of the IBM Model F keyboard that shipped with the original PC — 10 function keys (not 12) arranged in two columns on the left side of the keyboard.
Chart of Accounts and Posting
The chart of accounts supported totaling through a sum marker (adding an “S” would produce an asterisk and allow you to define a range of accounts to sum). Departments existed as a concept, though not as true dimensions — they were segments within the chart of accounts. Journal posting was straightforward and fast, with clear confirmation.
Under the Hood: The Technical Story
Some of the most fascinating aspects of PC Plus are found in its source code. Erik was able to show snippets of the code thanks to a special arrangement with Microsoft Legal — after signing the appropriate agreements, he was given permission to show portions of the source code for these historical products on YouTube.
Written in Pascal (and Assembler)
PC Plus was written in Poly Pascal, a Danish compiler created by Anders Hejlsberg. Poly Pascal later became what the world knows as Turbo Pascal. In an article from around 1985, Jesper explained that while most of the code could eventually be shown publicly (since the industry was evolving so quickly), certain pieces were held very close — specifically the menus and screen update routines, which were written in assembler for maximum performance.
Here is an example from the source code showing a function definition that reveals the Pascal heritage — and hints at what would eventually become AL:
function Today: String6;
Erik points out that this looks very much like Pascal, which is essentially what AL (Application Language, used in Business Central today) is a subset of. The key difference is that Pascal allows you to define custom types — in this case, String6 is a user-defined type that holds a date string. This type definition capability is the “very important piece of Pascal” that AL does not have.
Direct Screen Memory Access
The critical performance advantage of PC Plus came from how it handled screen output. In DOS, there were two ways to write to the screen:
- Through DOS — calling interrupt 21h, which was the standard but slow approach (this is what DAC Easy Accounting appeared to use)
- Direct video memory access — writing directly to the memory-mapped screen buffer, which required assembler code but was dramatically faster
The WriteScreen procedure accepted X and Y coordinates, an attribute (for colors/formatting), text content, and a length parameter. Because it wrote directly to video memory, it also needed to support the different graphics cards of the era — specifically the CGA card and the monochrome card:
procedure WriteScreen(X, Y: Integer; Attribute: Byte; Text: String; Length: Integer);
{ Inline assembler to write directly to video memory }
{ Check if BX = $B800 (CGA) or jump to monochrome handler }
The code included a check: if the video segment was at hex B800, it used the CGA code path; otherwise, it jumped to the monochrome handler. This direct memory access is what made PC Plus’s screens update so much faster than the competition.
Overlays: Breaking the 64K Barrier
Another clever technical solution dealt with DOS memory limitations. When creating executables in DOS, there were two options:
- .COM files — limited to 64K of total program size
- .EXE files — the format that survived to this day
Turbo Pascal (via Poly Pascal) provided an overlay system that allowed portions of the program to be swapped in and out of memory. Functions could be marked with an overlay attribute, meaning they would only be loaded into memory when needed:
{overlay} function SomeFunction: ...;
Erik compares this to attributes in AL. The overlay system meant that even though the program was constrained to 64K of code in memory at any one time, the total application could be much larger. Since only one screen or function was active at a time anyway, this was an elegant solution.
Business Success
PC Plus was priced at approximately $1,000 in 1985 — a significant sum at the time. By the 1986-87 fiscal year, PC&C had seven employees and was generating revenue of around one million dollars. The product had become a major success in Denmark.
The IBM Connection
The quality of PC Plus caught the attention of IBM, who were interested in a distribution arrangement. However, PC&C had already established a distribution agreement with another company in Denmark. At the time, software was typically sold bundled with hardware (for many buyers, this was their first computer), and PC&C could not maintain distribution agreements with two competing companies. The IBM arrangement never materialized — at least not at that time.
Looking Ahead
As networks started to emerge and the single-user limitation of PC Plus became a constraint, the team at PC&C began looking at what should come next. With the product’s success proving the market opportunity, the stage was set for something bigger.
In the next episode of the series, Erik promises to cover the IBM connection in more detail and the birth of Navigator version 1 — the next major step in the journey that would eventually lead to Navision and ultimately to Microsoft Dynamics 365 Business Central.
Summary
PC Plus represents the true origin story of Business Central. Created by three Danish engineering graduates in the early 1980s, it was a single-user accounting system that was dramatically more user-friendly and technically sophisticated than the award-winning competition of its day. Its Pascal codebase with assembler optimizations, overlay memory management, built-in help system, batch printing, and modular architecture laid the conceptual groundwork for everything that followed. The DNA of PC Plus — its module structure, its approach to the chart of accounts, its emphasis on usability — can still be traced through Navision, NAV, and into today’s Business Central.
