Dyalog Ltd.

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Dyalog's head office

Dyalog Ltd. (originally Dyadic Systems Ltd.) is a British company that specialises in APL products, especially developing Dyalog APL and providing consultancy services to Dyalog APL users.


Dyadic Systems consulting

Dyadic Systems was formed in 1976 by Ted Hare, Phil Goacher and David Crossley, a breakaway group of APL consultants from time-sharing bureau W.S. Atkins Computing. The group had been working on the Sigma APL processor, and was joined by other Atkins employees including Geoff Streeter and John Stembridge. Dyadic provided independent design and development services unaffiliated with any specific vendor. The steadily growing group of analysts gained a broad collective experience over numerous flavours of APL. While the emphasis remained with SHARP APL, APL*PLUS and Sigma APL, they also worked with APLs from IBM, DEC, Honeywell, Burroughs, and others, in addition to some non-APL languages. IBM was promoting VSAPL as its primary personal and departmental computing platform; this was a potential source of further demand for consulting.

During this period Dyadic hired Pauline Brand and Pete Donnelly.

Dyalog APL

The market for personal computers was quickly growing at the beginning of the 1980s. As a consulting rather than a timesharing business, Dyadic was not tied to the mainframe model, but was hindered by the small number of APL implementations for PC. One such implementation was in the firmware of the MCM micro. It had an idiosyncratic reverse implementation of the scan operator and limited the size of arrays to 255 elements along each axis. It provided the facilities to generate a GUI interface, at least in providing form-based input and output, but was slow. More substantial APLs had been implemented for the IBM 5110 and for the Motorola 68000 chip, available as Wicat computers. Even Bill Gates of Microsoft contemplated writing one, and talk to Ian Sharp of I.P. Sharp Associates about a reduced APL–how little one could get away with, but the project was cancelled before a product was released.

Dyadic Systems met with Zilog UK regarding the upcoming System 8000, or Z8000, microcomputer in 1981. Zilog wanted an APL for the Z8000, since the Swedish Ministry of Defence, in a call for tenders from Unix suppliers, had listed APL as a software requirement.

Dyalog (Europe) Ltd. was registered for this purpose in 1981. The new company blended both names, as mentioned in the press release:

This company is DYALOG (EUROPE) LIMITED, the name Dyalog being a hybrid derived from Dyadic and Zilog.

The “Marketing Strategy” paper read:

Our plan is to develop a low-price:

  • Industry-standard APL interpreter (Sharp look-alike but more comprehensive)
  • Running on an industry-standard 16-bit chip (Z8000)
  • Under an industry-standard operating system (UNIX)

Zilog provided Dyadic a dedicated Z8000 minicomputer and generous development facilities to develop Dyalog. Dyadic hired John Scholes, another former Atkins employee who had previously left to work as a developer on another APL implementation (for the ICL 2900) as designer and chief programmer for the project. Geoff Streeter and David Crossley joined Scholes as Dyalog implementors.

The choice to implement Dyalog in C on a UNIX system would later enable Dyalog APL to be ported to many other systems. The choice to make Dyalog a nested APL like NARS and the in-process APL2 would also have a major effect on Dyalog's development as a company.

Dyalog was released at the 1983 APL Conference in Washington, a venue it shared with vendors for APL.68000 and APL*PLUS/PC. Initial sales were slow due to the obscurity at the time of the nested array model, Unix operating system, and Zilog system in addition to Dyalog APL's poor performance relative to other APLs exhibited.

Purchase by Lynwood

In October 1983, Dyadic Systems, suffering both from decreasing consulting profits and poor sales of Dyalog APL, was purchased by computer terminal manufacturer Lynwood Scientific Developments Limited. Dyadic was allowed to maintain Dyalog APL under Lynwood for the next seven years despite continuous losses. Lynwood was acquired in 1988 by Hunting plc.

During this period Dyalog APL was ported to a large number of UNIX systems. While sales remained low, Simcorp began working with Dyalog in 1985. Simcorp remains a major user of Dyalog APL.

In 1986, Dyadic began to sell UNIX hardware to be used with their APL implementation, including the IBM 6150 in July of that year. Pauline Brand directed Dyadic's hardware division, a position she would maintain until its sale in 2002. British Airways was one client and eventually expanded its use of UNIX along with its relationship with Dyadic. In 1987 Dyalog APL for the 6150 became an IBM Vendor Logo product available directly from IBM, despite being in direct competition with IBM's APL2.

Dyadic hired Andy Cooke as Sales Manager and Andy Shiers as Customer Support Analyst in July 1987.

Independent ownership

In March 1990, John Scholes, Pauline Brand, and Peter Donnelly bought Dyadic Systems from Hunting plc. The purchase followed an informal offer by STSC in 1989, which had been rejected. Over the decade, the majority of Dyadic's profits were generated by hardware sales under Brand while Dyalog APL gained market share but failed to show comparable profits.

Dyadic added support for Dyalog APL on the Sun operating system and IBM's RS/6000 in 1990, which led to a growing user base in New York consisting of financial companies.

In 1991 John Daintree was hired to begin work on a graphical user interface, supporting the system function ⎕WC.

Also in 1991, Dyadic began collaborating with George Kunzle on the PC program which would later be named KPS (Kunzle Planning System). The two lead developers of KPS were Guy Haddleton and Morten Kromberg.

In 2000, Microsoft contacted Dyadic systems to ask for their participation in the project that would later be called .NET. Dyadic responded positively and began working on Dyalog.NET. The project was primarily a collaboration between John Daintree and Microsoft employees.

Dyalog Limited

In 2002 the software side of Dyadic Systems separated from the company, taking its current name Dyalog Ltd., and in 2003, the remainder of Dyadic Systems, then purely a hardware vendor, was sold to Syan Ltd. Following the separation, Dyalog had only five employees: John Scholes, Peter Donnelly, John Daintree, Geoff Streeter, and support staff Vincent Chan. The company maintained consistent profits despite its small size.

Takeover by Adaytum employees

In 2004, Donnelly approached Morten Kromberg and Gitte Christensen of Adaytum Software to ask them to take over management of the company. With backing from Simcorp and APL Italiana, the pair began leadership on 7 April 2005.

The Dyalog duck

While it is not an official logo, Dyalog is often associated with the rubber duck, and uses it to demonstrate graphical applications. Dyalog's office is home to over a hundred rubber ducks. Dyalog explains some of their history with ducks in "The Dyalog Duck".

The tradition began in 1989 when Peter Donnelly demonstrated the use of a graphics library for the newly supported DOS/386. Various members of the company continued to use ducks for similar purposes, with Donnelly and John Daintree the most prolific in this usage.


Dyalog arranges several recurring events (for dates see Dyalog's Event calendar):

External links


Social media

Functional programming conferences

In recent years, Dyalog has continuously presented at the following functional programming conferences:

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