Magma September 2009

magma@lists.squeakfoundation.org

6 participants
7 discussions

Passing objects between clients
by Nick Brown 25 Sep '09

25 Sep '09

Hi. I'm just trying out Magma for the first time. I'm interested in using it to allow pieces of work (which I'll call 'jobs') to be handed out to one or more Squeak images ('workers'). On startup, each worker opens a connection to the Magma server, checks to see whether there are any jobs waiting to be done. If there are, the worker will take the first job off the queue, run it, and ultimately commit the result of the job back into Magma. Other Magma clients are periodically going to push new jobs onto the end of the queue. My first attempt just used an OrderedCollection to represent the queue, with one Magma client adding Arrays of numbers to it with #add: to simulate jobs being added; and another client removing them with #removeFirst; to simulate jobs being accepted by a worker. This approach is prone to conflicts, presumably because each #add: or #removeFirst: is attempting to rewrite the entire internal state of the OrderedCollection. So my question is, is there a better way of doing this? Use Magma to pass semaphores between clients? Or just live with the conflicts? Thanks for any insight. -Nick

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[Fwd: Fix to Magma seasideHelper]
by Miguel Enrique Cobá Martinez 18 Sep '09

18 Sep '09

-- Miguel Cobá http://miguel.leugim.com.mx

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MagmaCollection
by Ross Boylan 15 Sep '09

15 Sep '09

Does MagmaCollection preserve order, so that standard collection methods will always go through objects in the order of original insertion? While doing some tests for that I ran into "Instances of MagmaCollection are not indexable" while using at: at: index "Primitive. Assumes receiver is indexable. Answer the value of an indexable element in the receiver. Fail if the argument index is not an Integer or is out of bounds. Essential. See Object documentation whatIsAPrimitive." <primitive: 60> index isInteger ifTrue: [self class isVariable ifTrue: [self errorSubscriptBounds: index] ifFalse: [self errorNotIndexable]]. index isNumber ifTrue: [^self at: index asInteger] ifFalse: [self errorNonIntegerIndex] The test was |c| c := MagmaCollection new. c add: 1; add: 2; add: 3. c do: [:x | Transcript show: x]. Transcript cr. c remove: 2. c do: [:x | Transcript show: x]. Transcript cr. c add: 4. c do: [:x | Transcript show: x]. Transcript cr. Transcript show: (c at: 2); cr. and the error was in the last line. BTW, 4 did appear after 3 in the printout, not in the hole created from removing 2. So it looks as if insertion order is preserved. I did NOT have a magma session open when I ran the test. I was expecting at: to work since http://wiki.squeak.org/squeak/2639 says that MagmaCollection "Provides size and absolute position access (at: anInteger) making it suitable for scrolling lists". Finally, is it advisable to use the standard collection methods if the MagmaCollection is large, or is it better to use a reader? By "better" I am mostly thinking of whether the entire collection is forced into memory or not. Since the standard collection methods return a "self species", which is a Bag, I'm guessing it's better to use a reader. Thanks. Ross Boylan

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Magma test failure
by Ross Boylan 12 Sep '09

12 Sep '09

Shortly after starting the test _magmaTestclient1.image show "MagmaUserError: WriteBarrier requires NewCompiler." Hmm, I was going to copy the tail end of the Transcript of _magmaTestConductor into this message, but that image is unresponsive. I'm running on Debian GNU/Linux with squeak-vm 3.10.3+svn1902.dfsg-1 and the 3.10 image downloaded from http://ftp.squeak.org/3.10/Squeak3.10.2-7179-basic.zip. Magma was tested with 3.10.4 (VM). Is the new compiler something added with the 3.10.4 release? I see a package by that name on SM (marked as very alpha).

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magma VM requirements
by Ross Boylan 09 Sep '09

09 Sep '09

Does magma require a VM with closures? By this I mean any requirement beyond what the underlying platform needs; I think Pharo and Seaside both need a VM with closures. That is more recent than the version in the current Debian release (Lenny). I think 3.10.4, which http://wiki.squeak.org/squeak/2657 recommends, has closures. Ross

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magma with Pharo
by Ross Boylan 09 Sep '09

09 Sep '09

Since I ran into trouble with the squeak 3.10 image, I figured I'd try pharo. I had some trouble following the instructions, and thought it would be useful to report things that held me up. This might suggest changes to the documentation. Getting pharo running wasn't entirely smooth, though that's mostly a pharo, not magma issue. Some of their instructions are a bit off, and the image wouldn't run with the VM I had. After downloading their VM (on Linux) I got it going, using the full http://gforge.inria.fr/frs/download.php/23087/pharo1.0-10440-BETAdev09.09.1… image. It was unclear whether I should get updates after starting the image; I did. Now to the magma install instructions (http://wiki.squeak.org/squeak/2657). This time I tried using Monticello: Step 1. "Make sure you have Monticello Configurations working (see Monticello Configurations in 3.9)." The instructions on the first link (http://wiki.squeak.org/squeak/6058) say "select World Menu | open... | Monticello Configurations". The pharo menus are not arranged that way. I did Tools | More | Monticello configurations. Once it opened, blank, I thought I was supposed to load or test something (wiki 6058 goes on "To load an existing configuration, select the configuration from Monticellos repository browser") in the window that I just opened. The link to MC Configurations in 3.9 says to install 2 files (in a 3.9 image); I figured I already had it, so did nothing. So I think I could have skipped the whole MC Configurations thing, which is what I did (except it took awhile to guess that was the right move). Step 2. I went to the MC browser and clicked on +Repository, selected http, and edited the dialog to match what page 2657 said. However, no packages appeared at the bottom of my package list (left hand pane of MC browser). I opened the repository and found r42final. Then I spent some time wondering if this had the test suite in it, and looking at some versions that had Magma Tester in the name. The description on the installation page says "Magma" houses prior "stable" releases of Magma in each of its three configurations (Client, Server and Tester). "MagmaTester" houses the prior stable releases as well as the current development release. This made me think there would be separate files for each configuration. I looked at the r42final component list, saw the tester in there, and installed it. BTW, http://wiki.squeak.org/squeak/2657 in this section has steps 1 and 2 followed by steps 1 and 2. Finally, I want to run the test suite. OSProcess does not show up in MC, and Pharo doesn't seem to have a package universe tool. The package developer advised using squeaksource, but that doesn't seem to have worked either (the pharo list has the gory details). Ross Boylan

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r42 "not published yet"
by Ross Boylan 09 Sep '09

09 Sep '09

Trying to follow along with the installation instructions at http://wiki.squeak.org/squeak/2657 I noticed some issues. I was using http://ftp.squeak.org/3.10/Squeak3.10.2-7179-basic.zip for the image. I followed the "Installing Magam for SqueakMap" instructions. First, I doubt that a newbiew would be able to locate the squeak map application. I brought up an object browser, and even that listed to squeak map objects (one was squeamap-ui). So it might be useful to make that a little more explicit. Second, r42 was not in squeak map when I launched it. It was after I updated from the net, but again, the installation instructions don't say anything about that. Third, when I did to install the r42 release of magma tester, I got a message that the code had not yet been published. Finally, the description listed in the package loader for r42Final seem off; they give release dates that precede the release of r42. Or are those release dates for Squeak? In retrospect I suppose Monticello would have been a better choice; I just did what was on the page first. I'll kick off the test and see what happens; I'm on Debian Lenny which has squeak-vm 3.10.3+svn1902.dfsg-1. That's a bit before the known good VM of 3.10-4. Ross Boylan

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Magma September 2009