[igouy]

Does "originally" mean before release from the offices and corridors of Xerox Palo Alto Research Center.

Perhaps further back: before change sets, before fileOut, before sources and change log ? There's a lot of history.

I wonder if the Digitalk Smalltalk implementation "has objects inside that go back to 1977".

[em-bee]

with originally i meant before the use of version control systems became common and expected. i don't know the actual history here, but i just found this thread that looks promising to contain some interesting details: https://news.ycombinator.com/item?id=15206339 (it is also discussing lisp which bring this subthread back in line with the original topic :-)

[igouy]

In that case

https://news.ycombinator.com/item?id=47354288

[em-bee]

that's very interesting, thank you, i should have realized that even early on there had to be a way to share code between images. (and i don't know why i missed that comment before responding myself)

but, doesn't building a new system image involve taking an old/existing image, adding/merging all the changes, and then release new image and sources file from that?

in other words, the image is not recreated from scratch every time and it is more than just a cache.

what is described there is the process of source management in the absence of a proper revision control system. obviously when multiple people work on the same project, somewhere the changes need to be tracked and merged.

but that doesn't change the fact that the changes first happen in an image, and that you could save that image and write out a new sources file.

[igouy]

Sorry I failed to notice your reply.

> image is not recreated from scratch every time and it is more than just a cache

Yes, some vm & image & sources & changes can be taken as the base implementation for development purposes -- a persistent cache.

The state of whatever IDE tools were in use will be saved -- is that what makes you say "more than just a cache"? If I sleep a windows desktop is that more than just a cache?

> changes first happen in an image

What if I write a plain-text source code file using Notepad, and use Smalltalk file handling and byte code compilation and command-line argument handling (packaged in the image) to write the result of a computation to stdout (and quit the image without saving)?

[em-bee]

If I sleep a windows desktop is that more than just a cache?

yes, so basically what i meant here is that a cache just stores data, but it doesn't store the whole application.

this is significant in that i can shut down an application (say my webbrowser), then i can upgrade it to a new version, restart and and the application will reinitialize itself and load data from the cache, but now i have a new version of the application.

whereas if i put my laptop to sleep, or better yet, hibernate, then the whole state of the laptop is frozen in place, and i can't do anything to it until i run it again. same is true for smalltalk images.

What if I write a plain-text source code file using Notepad, and use Smalltalk file handling and byte code compilation and command-line argument handling (packaged in the image) to write the result of a computation to stdout (and quit the image without saving)?

you could be doing that, but then you would use the image as your IDE and runtime environment, but not building the actual application in your image. so you wouldn't using what i have been taught is the traditional way of doing smalltalk development.

i am not trying to be pedantic here. it does not matter either way. i just find the smalltalk image approach interesting because it forces you to think about software development in a different way.

this mattes to me because i am working with a web development platform (written in pike) that uses a similar approach. albeit more by accident than intentional. the developers of the platform added support for programmable objects that are stored in the platforms database. these objects can change the behavior of the platform itself, like plugins, but because they are stored in the database they can be changed at runtime, like a smalltalk image. and all the same implications for doing that apply here too. the database becomes more than a cache. and in theory the whole platform could be rewritten such that almost all of its code is stored in the database and only a small bootstrapping system needs to remain outside. this is simply made possible because pike can load and update code at runtime and code changes can be applied without restarting, just like smalltalk.

the downside of the image approach is that it makes upgrading the base image harder, because there is no clear distinction between the base image and any user added changes. i kind of have to take extra steps to pick out my changes and apply them to a new image.

it would be interesting if that process could be improved. it probably would require some compartmentalization just like an OS where i have the base OS, my home directory and the system configuration. i can take a disk image, upgrade the OS and the rest still works. it would be nice if upgrading pharo for example would work the same way.

btw: thanks for the email. i have to ask, how did you manage to reply to a comment more than a month old. normally the reply function is disabled on comments that are 14 days old.

[igouy]

> traditional way of doing smalltalk development

Is that in-conflict with a reproducible build process or can we have both.

> makes upgrading the base image harder, because there is no clear distinction between the base image and any user added changes.

We've been keeping "user added changes" in external files? (Plus the changes file.)

Port "user added changes" from the source code archive to each vendor release.

(btw: I ask nicely and don't abuse this small kindness.)