I know very little about Smalltalk but I noticed that there's a frequent mention of the "kernel". Dan Ingalls prime maintainer of several implementations of Smalltalk also worked on a Javascript environment called "Lively Kernel" and in Peter Siebel's book he kept mentionning the "kernel".

I cannot help but think that it is no coincidence that the creators of Smalltalk used the name of a (central) part of operating systems to refer to a particular component of their language.

Was it because Smalltalk intended to act as an operating system? Was it because theory behind programming languages and operating systems have a lot in common?

What is the reason behind the common appelation of the two components?

  • 7
    Fredholm integral equations are therefore similar to the operating systems and programming languages. Interesting.
    – SK-logic
    Aug 31, 2012 at 12:22

2 Answers 2



These are two different meanings of the same word.

But you are correct to observe that Smalltalk has a lot of an operating system. This is because early Smalltalk systems predate today's operating systems and thus Smalltalk offers many services that are typically offered by the operation system today.

  • Also worth noting that people working with Operating Systems often find themselves working with Programming Languages as well and visa versa, and since both have core functionality which also typically involves having runtime images(eg string tables, functions language inherits from the runtime, vtables, so on), there is a lot of overlap.
    – Dmytro
    Oct 25, 2016 at 13:06

Yes, originally Smalltalk was its own operating system, written in itself (the 'kernel'), with a graphical user interface featuring windows and the use of a 3-button mouse. Although Alan Kay did not invent the GUI or the mouse, he did invent the model-view-controller paradigm and was the first to actually make use of them. The article in the Smalltalk BYTE issue -- the cover sported a hot-air balloon -- bluntly said that an operating system was what a language failed to do, because it wasn't powerful enough, but as for Smalltalk, it was and did. The Smalltalk system featured the first graphical integrated development environment and debugger; the IDE was the GUI, why should they be separate? It came with a class hierarchy browser, for instance, in windows with panes, another first. All this with a syntax so simple that it fits on the back of a post card. Except for GNU "Smalltalk," modern Smalltalks carry on the tradition, although now they have been modified to run within the confines of an OS. You don't shut Smalltalk down, you save it, and when you fire it up again, everything is precisely as it was, to the position of the cursor itself. The size? Squeak runs at 102 MB, while Pharo runs at 140 MB. Three files.

  • 3
    this post is rather hard to read (wall of text). Would you mind editing it into a better shape?
    – gnat
    Oct 30, 2017 at 5:01

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