It appears that the latest official 3.3alpha and 3.2gamma images both have a significant, and perniciously dangerous, bug, which seemingly arrived in update 4897.
Until this bug is fixed, it is *very dangerous* to be using any image that has update 4897 in it, because each time you try to snapshot such an image ("save", "save and quit", etc.) you stand a good chance of losing the image.
Thus, ironically, the only way to assure that you won't lose such an image is never to save it. Which however makes development work problematical.
Anyone who has not recently updated 3.3alpha past 4889 or updated 3.2gamma2 past 4889 or started using 3.2gamma3 is advised to hold off on doing so. Up-to-date 3.3a and 3.2gammaX images will all be in a very dangerous state in which to save them is potentially to lose them.
Stay tuned...
-- Scott
PS: Reverting method ProcessorScheduler class.idleProcess *appears* to circumvent the problem.
Scott Wallace scott.wallace@squeakland.org is claimed by the authorities to have written:
It appears that the latest official 3.3alpha and 3.2gamma images both have a significant, and perniciously dangerous, bug, which seemingly arrived in update 4897.
That's curious - I've saved and restarted 4899 images a bunch of times on both Acorn and Mac/osx. What is the symptom?
I did notice that the sources for the 4897 change appears to get lost, though no others are harmed (4898 ok etc)
tim
Squesk refuses to start, it shows a debug window before quickly exiting to the OS.
On Monday, July 1, 2002, at 10:13 AM, Tim Rowledge wrote:
Scott Wallace scott.wallace@squeakland.org is claimed by the authorities to have written:
It appears that the latest official 3.3alpha and 3.2gamma images both have a significant, and perniciously dangerous, bug, which seemingly arrived in update 4897.
That's curious - I've saved and restarted 4899 images a bunch of times on both Acorn and Mac/osx. What is the symptom?
I did notice that the sources for the 4897 change appears to get lost, though no others are harmed (4898 ok etc)
tim
Tim Rowledge, tim@sumeru.stanford.edu, http://sumeru.stanford.edu/tim Strange OpCodes: IO: Illogical Or
At 7:13 PM -0700 6/30/02, Tim Rowledge wrote:
Scott Wallace scott.wallace@squeakland.org is claimed by the authorities to have written:
It appears that the latest official 3.3alpha and 3.2gamma images both have a significant, and perniciously dangerous, bug, which seemingly arrived in update 4897.
That's curious - I've saved and restarted 4899 images a bunch of times on both Acorn and Mac/osx. What is the symptom?
The symptom is a VM error alert (in a Mac modal dialog if on a Mac) saying "Scheduler could not find a runnable process," appearing upon coming back from a snapshot -- either immediately after a "save" is issued in a running image or, after a save-and-quit, upon the next startup. In either situation, the vm is dead in the water.
Behind the VM alert, on the Squeak desktop, a pre-debug notifier is visible whose message is "Error: attempt to evaluate a block that is already being evaluated".
It does not happen every time -- it is a timing-related issue. But -- on the Mac anyway -- if you keep on making snapshots it seemingly will always *eventually* happen. Sometimes it happens on the first or second save, sometimes it takes more. And when it does happen, your image is hosed. It's akin to Russian roulette.
The problem has been seen at least on the PC and on Mac/Classic.
-- Scott
PS: I wonder how you ever got an image with update level 4899? The next burst of updates after 4889 took it straight to 4904 iirc.
Squeak3.2gamma3 has now been removed from the UIUC server, and replaced by Squeak3.2gamma4, which does not have the "What is this error?" bug.
Update 4905, now published to 3.2gamma and also to 3.3alpha, reverts the critical method and contains a do-it provided by Andreas that guards against conditions that could arise if one had earlier updated past 4897 and then had managed to snapshot successfully.
If you happen to have a 3.2gamma3 image around, it should be okay to use it provided that you load updates before you next make a snapshot.
-- Scott
At 3:58 PM -0700 6/30/02, Scott Wallace wrote:
It appears that the latest official 3.3alpha and 3.2gamma images both have a significant, and perniciously dangerous, bug, which seemingly arrived in update 4897.
Until this bug is fixed, it is *very dangerous* to be using any image that has update 4897 in it, because each time you try to snapshot such an image ("save", "save and quit", etc.) you stand a good chance of losing the image.
Thus, ironically, the only way to assure that you won't lose such an image is never to save it. Which however makes development work problematical.
Anyone who has not recently updated 3.3alpha past 4889 or updated 3.2gamma2 past 4889 or started using 3.2gamma3 is advised to hold off on doing so. Up-to-date 3.3a and 3.2gammaX images will all be in a very dangerous state in which to save them is potentially to lose them.
Stay tuned...
-- Scott
PS: Reverting method ProcessorScheduler class.idleProcess *appears* to circumvent the problem.
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