KOL and MCK

A reference on Object Pascal, the Delphi line and the libraries built on it.

Delphi form designer mid-drag on a CRT monitor, component palette open at right, adult developer's hand on the mouse at the edge of the frame, screen the brightest light source in the room

Delphi · the component

Somebody dragged a button onto a form and the industry changed shape

Delphi 1, 1995: a visual designer over a native compiler, on 16-bit Windows. Photo: cottonbro studio / Pexels

1970

Niklaus Wirth publishes Pascal — a language drawn so a compiler can read it in one direction only.

1983

Anders Hejlsberg's Turbo Pascal ships for Borland: editor, compiler and linker in one program, on one floppy.

1993

Florian Klämpfl starts Free Pascal. Lazarus follows in 1999 and the language stops depending on one vendor.

The argument was never about the language. It was about how much you had to ship with it.

The VCL gave every Delphi application a floor of several hundred kilobytes before a line of your own code went in. Vladimir Kladov's Key Objects Library refused the hierarchy and did the same visible work in tens.

Read the piece on KOL and MCK

Diagram comparing filled and empty circles representing bits against sphere symbols representing qubits

A diagram of bit states. KOL's case was arithmetic — the same visible work, an order of magnitude fewer bytes.

Photo: Google DeepMind / Pexels

Where the language came from, what it became, and what it cost to run

All 27 pieces

Niklaus Wirth photographed at ETH Zürich, or a printed Pascal program listing on fanfold paper under a desk lamp

The Language Niklaus Wirth Designed at ETH Zürich

Wirth's 1970 report ran to a few dozen pages; the language it defined outlived every machine it was first compiled for.

 Delphi 1 retail box, CD and printed manual set arranged on a desk, 1995 Borland packaging and logo legible, warm tungsten light

Delphi 1, February 1995

A visual form designer over a native compiler, on 16-bit Windows.

 Windows file properties dialog for a compiled KOL application showing file size in the tens of kilobytes, beside the same dialog for an equivalent VCL build

Vladimir Kladov and the Thirty-Kilobyte Argument

A flatter object model, and a binary a fraction of the size.
A conference room at a Delphi-era developer event, projector displaying a code slide, adult audience members seated, speaker at the front

After Borland

CodeGear in 2006, Embarcadero in 2008, and a compiler that outlasted both announcements

Six pieces in After Borland

Delphi-era developer conferences were where version changes got argued out in front of the people who had to migrate.

Photo: Matheus Bertelli / Pexels

Two decisions the whole component model rests on

Seven pieces in Delphi

The VCL class hierarchy tree in the Delphi help browser, or a component's source unit open in the Delphi code editor

The VCL Made the Component the Unit of Work

Every VCL control inherits several generations of behaviour before a developer writes a line of their own.
Close-up of HTML code on a screen showing a button link labeled "Sign up today"

A Form Saved as a Text File You Could Read

A form's entire component tree, written out as name-value pairs a person could read and a diff tool could merge.

Borland sold it in 2006 and again in 2008. It is still compiling.

Fifteen years of keeping it alive →

The four names the record keeps returning to

Five pieces in People

Bearded man in glasses and suit jacket speaking into a microphone at a podium

Niklaus Wirth

Designer of Pascal, ETH Zürich

 Four 3.5-inch floppy disks labeled Borland Turbo Pascal, numbered disk 1 through 4 of 4

Anders Hejlsberg

Author of Turbo Pascal; chief architect of Delphi

 person typing on a keyboard beside a vintage computer with blue-screen code display

Vladimir Kladov

Author of the Key Objects Library and Mirror Classes Kit

 Rows of vintage CRT monitors display glowing text and code in a dim room

Florian Klämpfl

Founder of the Free Pascal compiler project

Photographs: Wikimedia Commons; Pexels; generated for this site.

KOL and MCK Set and kept up with the support of