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Scratch with Tim Rowledge at ROUGOL

Thu May 15, 2014 11:00 pm

At the RISC OS User Group Of London meeting on Monday 19th May 2014 we will be looking at the Scratch beginners programming language and the Squeak/Smalltalk environment on which it is based.

We are very pleased that long time Squeak developer Tim Rowledge will be joining us via video call from his home in Canada. He has been an advocate of ARM based systems since the 80s and did the original port of Smalltalk to RISC OS while it was in beta testing. Since then it has been all Smalltalk (of various forms) on ARM (of various forms) up to the present Squeak on Raspberry Pi.

Tim has recently been working on optimising Squeak for the Raspberry Pi, on Linux and RISC OS, and is happy to answer questions about its history and recent developments. ROUGOL meetings are free so come along and join in the discussions.

http://www.rougol.jellybaby.net/

timrowledge
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Re: Scratch with Tim Rowledge at ROUGOL

Sun May 18, 2014 12:07 am

If you're *really* interested in Smalltalk and ARM history you might enjoy listening to a podcast interview I did last year. I'll be honest - it's long and probably ought to have been edited down but it's their podcast and Joachim, Marten & Sebastian decided to keep it all.

http://smalltalkinspect.podspot.de/post ... -rowledge/
Making Smalltalk on ARM since 1986; making your Scratch better since 2012

JonD
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Re: Scratch with Tim Rowledge at ROUGOL

Wed Jul 09, 2014 3:44 pm

Hi Tim,
is there any way of getting hold of the beta version of Scratch you are working on? All the old links lying around point to zipfiles that are long since gone.

Trying to avoid being forced to boot Raspian when my son want's to do some Scratch programming!

Best regards
Jon

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AndrewS
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Re: Scratch with Tim Rowledge at ROUGOL

Wed Jul 09, 2014 3:54 pm

https://github.com/raspberrypi/scratch :)

Edit: Although that's probably the Raspbian version rather than the RISC OS version :oops:

timrowledge
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Re: Scratch with Tim Rowledge at ROUGOL

Fri Jul 11, 2014 5:19 am

JonD wrote:Hi Tim,
is there any way of getting hold of the beta version of Scratch you are working on? All the old links lying around point to zipfiles that are long since gone.
We moved things over to the Pi GitHub, so pop over to https://github.com/raspberrypi/scratch and download the nuScratchBeta5.tgz

So far as I'm aware RISC OS tools can handle the tgz files, but I haven't actually tried it so do let me know if it is a problem. All you need to extract is the matched pair of .image/.changes files.

It won't be quite as fast on the current RISC OS Squeak vm but I simply don't have any time spare to wind up the StackVM version for it; there's quite a bit of tricky stuff to do with synchronisation across threads, write barriers etc, and a nasty bit of rewriting that would likely be needed to live with RISC OS interrupt handling. Maybe when the fully-leaded CogVM is up and running on Raspbian (getting there ! It's hard, bit-wrangling, screen-peering work) it would be worth the effort, but I can't make promises as yet. Money is always an issue with these things.
Making Smalltalk on ARM since 1986; making your Scratch better since 2012

JonD
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Re: Scratch with Tim Rowledge at ROUGOL

Fri Jul 11, 2014 9:22 am

Hi Tim,
ooh splendid! Does the tarball contain the Squeak VM as well? I assumed it would be seperate, but I couldn't even find Squeak on either RISCOS Store or !Packman.

Best regards
Jonathan

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Re: Scratch with Tim Rowledge at ROUGOL

Fri Jul 11, 2014 4:34 pm

[quote="JonD"Does the tarball contain the Squeak VM as well? I assumed it would be seperate, but I couldn't even find Squeak on either RISCOS Store or !Packman.[/quote]
Aargh! Someday I should find out how to get !Squeak listed but for now it lives at http://squeakvm.org/riscos/ I recommend the 4.0 release on RISC OS because new and exciting features in 4.4 rather stretch the performance ability of a Pi. The later version works - but feels a bit treaclish. And I don't care if spelling check doesn't like treaclish, it's a word, dammit!

All you need to do is download http://squeakvm.org/riscos/release/Sque ... OS-4-0.zip and open it up in the usual manner. Drag the !Squeak application wherever you put these things and then do the minor (and annoying but currently unavoidable) module wrangling described in the read me files. Quickly test by d-clicking on the image file to make sure the aliases etc are set up and the vanilla system fires up ok.

To make the Scratch system work you merely need to extract the above mentioned scratch .image & .changes files and, crucially, set the filetype of the .image file to STimage (&FAA). You can leave the .changes file as whatever it is or set it to text.

I *think* that is all you need to do. It's always interesting trying to explain stuff like this to someone new to it; you learn so much about things you are simply assuming without foundation.
Making Smalltalk on ARM since 1986; making your Scratch better since 2012

JonD
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Re: Scratch with Tim Rowledge at ROUGOL

Sat Jul 12, 2014 9:11 am

Outstanding (and very entertertaining!) thanks!
I'll give it a whirl. No more loooong waits for Raspian to boot!

JonD
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Re: Scratch with Tim Rowledge at ROUGOL

Mon Jul 14, 2014 8:59 pm

Edit: Scratch that (no pun intended). I was trying to run Scratch *as well as* Squeak and running out of memory,
It's running perfectly now! Thanks!

HI Tim,
I got Squeak up and running, but I'm not sure how to get it to execute the Scratch image. There doesn't seem to be a Squeak filetype. I changed the type to STimage but I just get an error when I double click it. "Unable to allocate Object Memory".
Do I need ti fiddle with sliders?

Best regards
Jonathan

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