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.

External links



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

Social media

Functional programming conferences

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

APL community [edit]
Activities ConferencesAdvent of CodeAPL CampfireAPL CultivationAPL Meetup (Portuguese) ∙ APL Problem Solving CompetitionAPL SeedsArray CastBAA sessionsCode golfDyalog user meetingsDyalog webinarsIverson AwardSharing code
User groups APL Borealis (Canada) ∙ APL et J (France) ∙ APL Germany (terminology) ∙ BAA (UK) ∙ FinnAPL (Finland) ∙ JAPLA (Japan) ∙ SAUG (Switzerland) ∙ SIGAPL (USA) ∙ SwedAPL (Sweden)
People Phil AbramsBrian BeckerBob BerneckyLarry BreedCharles BrennerJim BrownAdám BrudzewskyGitte ChristensenPeter DonnellyAdin FalkoffGarth FosterAaron HsuRoger HuiKen IversonMorten KrombergMarshall LochbaumEugene McDonnellJon McGrewDonald McIntyreRoger MooreAlan PerlisAl RoseWilliam RutiserJohn ScholesIan SharpBob SmithGeoff StreeterRoy SykesArthur Whitney
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