<br><br><div class="gmail_quote">On Sat, Mar 7, 2009 at 11:23 AM, John M McIntosh <span dir="ltr"><<a href="mailto:johnmci@smalltalkconsulting.com">johnmci@smalltalkconsulting.com</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex;">
<br>
Ah, I have a bias opinion for an answer, but I'll not discuss that here.<br>
<br>
However the BIG issue for the 3.8.x and earlier series of macintosh carbon VM is their behaviour for opening a closure image.<br>
What you will find is that if you attempt to open a closure image the squeak.app will start then terminate<br>
It will print a diagnostic message to the console which you can see via Apple's Console.app found in Applications/Utilities.<br>
<br>
07/03/09 11:11:51 AM [0x0-0x8d08d].org.squeak.Squeak[1894] This interpreter (vers. 6502) cannot read image file (vers. 6504).<br>
07/03/09 11:11:51 AM [0x0-0x8d08d].org.squeak.Squeak[1894] Press CR to quit...<br>
<br>
The reason for this behaviour is that 15 some years back John Maloney coded up the version checking logic and there was a question<br>
what to do now. At the time CodeWarrior under os-7.5.x would helpfully put up a dialog window if you printed to the *console* and did<br>
a getchar for the answer, that code has moved forward for years now and no-one really has tested until now.<br>
<br>
Interestingly the getchar on os-x does not block and returns null and we terminate the VM, but the behaviour is confusing if you don't<br>
understand what is going on.<br>
<br>
I will at some point push out a 3.8.22 VM that should put up a more helpful dialog message, but people who have older VMs underfoot<br>
should realize this behaviour should be an indication that perhaps your VM is too old.</blockquote><div><br></div><div>yes, please. I stumbled across the code this week and the last few statements don't make sense on a number of platforms, because they presume a command-line:</div>
<div><br></div><div><div>checkImageVersionFrom: f startingAt: imageOffset</div><div><span class="Apple-tab-span" style="white-space:pre"> </span>"Read and verify the image file version number and return true if the the given image file needs to be byte-swapped. As a side effect, position the file stream just after the version number of the image header. This code prints a warning and does a hard-exit if it cannot find a valid version number."</div>
<div><span class="Apple-tab-span" style="white-space:pre"> </span>"This code is based on C code by Ian Piumarta."</div><div><br></div><div><span class="Apple-tab-span" style="white-space:pre"> </span>| version firstVersion |</div>
<div><span class="Apple-tab-span" style="white-space:pre"> </span><var: #f type: 'sqImageFile '></div><div><span class="Apple-tab-span" style="white-space:pre"> </span><var: #imageOffset type: 'squeakFileOffsetType '></div>
<div><br></div><div><span class="Apple-tab-span" style="white-space:pre"> </span>"check the version number"</div><div><span class="Apple-tab-span" style="white-space:pre"> </span>self sqImageFile: f Seek: imageOffset.</div>
<div><span class="Apple-tab-span" style="white-space:pre"> </span>version := firstVersion := self getLongFromFile: f swap: false.</div><div><span class="Apple-tab-span" style="white-space:pre"> </span>(self readableFormat: version) ifTrue: [^ false].</div>
<div><br></div><div><span class="Apple-tab-span" style="white-space:pre"> </span>"try with bytes reversed"</div><div><span class="Apple-tab-span" style="white-space:pre"> </span>self sqImageFile: f Seek: imageOffset.</div>
<div><span class="Apple-tab-span" style="white-space:pre"> </span>version := self getLongFromFile: f swap: true.</div><div><span class="Apple-tab-span" style="white-space:pre"> </span>(self readableFormat: version) ifTrue: [^ true].</div>
<div><br></div><div><span class="Apple-tab-span" style="white-space:pre"> </span>"Note: The following is only meaningful if not reading an embedded image"</div><div><span class="Apple-tab-span" style="white-space:pre"> </span>imageOffset = 0 ifTrue:[</div>
<div><span class="Apple-tab-span" style="white-space:pre"> </span>"try skipping the first 512 bytes (prepended by certain Mac file transfer utilities)"</div><div><span class="Apple-tab-span" style="white-space:pre"> </span>self sqImageFile: f Seek: 512.</div>
<div><span class="Apple-tab-span" style="white-space:pre"> </span>version := self getLongFromFile: f swap: false.</div><div><span class="Apple-tab-span" style="white-space:pre"> </span>(self readableFormat: version) ifTrue: [^ false].</div>
<div><br></div><div><span class="Apple-tab-span" style="white-space:pre"> </span>"try skipping the first 512 bytes with bytes reversed"</div><div><span class="Apple-tab-span" style="white-space:pre"> </span>self sqImageFile: f Seek: 512.</div>
<div><span class="Apple-tab-span" style="white-space:pre"> </span>version := self getLongFromFile: f swap: true.</div><div><span class="Apple-tab-span" style="white-space:pre"> </span>(self readableFormat: version) ifTrue: [^ true]].</div>
<div><br></div><div><span class="Apple-tab-span" style="white-space:pre"> </span>"hard failure; abort"</div><div><span class="Apple-tab-span" style="white-space:pre"> </span>self print: 'This interpreter (vers. '.</div>
<div><span class="Apple-tab-span" style="white-space:pre"> </span>self printNum: self imageFormatVersion.</div><div><span class="Apple-tab-span" style="white-space:pre"> </span>self print: ') cannot read image file (vers. '.</div>
<div><span class="Apple-tab-span" style="white-space:pre"> </span>self printNum: firstVersion.</div><div><span class="Apple-tab-span" style="white-space:pre"> </span>self print: ').'.</div><div><span class="Apple-tab-span" style="white-space:pre"> </span>self cr.</div>
<div><span class="Apple-tab-span" style="white-space:pre"> </span>self print: 'Press CR to quit...'.</div><div><span class="Apple-tab-span" style="white-space:pre"> </span>self getchar.</div><div><span class="Apple-tab-span" style="white-space:pre"> </span>self ioExit.</div>
<div><br></div></div><div> We should replace the last phrase with something like</div><div><br></div><div> self ioReportImageFormat: firstVersion incompatibleWith: self imageFormatVersion andThenExit: nil</div><div><br>
</div><div>and let the platform deal with this as it chooses.</div><div><br></div><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex;"><div><div></div><div class="h5"><br>
<br>
<br>
On 7-Mar-09, at 8:12 AM, Andreas Raab wrote:<br>
<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
Bert Freudenberg wrote:<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
John bumped the Mac VM's major version to 4 to signify closure support. Maybe the other platforms should follow suit?<br>
</blockquote>
<br>
I figured v4 would signify the Stack VM or later as this VM will no longer be able to run v3 images. The current set of VMs are fully backwards compatible so I consider them logically to be v3 VMs.<br>
<br>
But I'm willing to reconsider if people prefer the v4 terminology.<br>
<br>
Cheers,<br>
- Andreas<br>
</blockquote>
<br></div></div><font color="#888888">
--<br>
===========================================================================<br>
John M. McIntosh <<a href="mailto:johnmci@smalltalkconsulting.com" target="_blank">johnmci@smalltalkconsulting.com</a>><br>
Corporate Smalltalk Consulting Ltd. <a href="http://www.smalltalkconsulting.com" target="_blank">http://www.smalltalkconsulting.com</a><br>
===========================================================================<br>
<br>
<br>
<br>
</font></blockquote></div><br>