<div dir="ltr">Hi David,<br><div class="gmail_extra"><br><div class="gmail_quote">On Fri, Jul 8, 2016 at 4:11 PM, David T. Lewis <span dir="ltr"><<a href="mailto:lewis@mail.msen.com" target="_blank">lewis@mail.msen.com</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><span class="">On Fri, Jul 08, 2016 at 03:35:35PM -0700, Eliot Miranda wrote:<br>
> Hi Tobias,<br>
><br>
> On Wed, Jul 6, 2016 at 12:23 AM, Tobias Pape <<a href="mailto:Das.Linux@gmx.de">Das.Linux@gmx.de</a>> wrote:<br>
><br>
> ><br>
> > On 06.07.2016, at 08:17, Eliot Miranda <<a href="mailto:eliot.miranda@gmail.com">eliot.miranda@gmail.com</a>> wrote:<br>
> ><br>
> > > On Tue, Jul 5, 2016 at 10:21 PM, Tobias Pape <<a href="mailto:Das.Linux@gmx.de">Das.Linux@gmx.de</a>> wrote:<br>
> > ><br>
> > > On 06.07.2016, at 01:13, <a href="mailto:commits@source.squeak.org">commits@source.squeak.org</a> wrote:<br>
> > ><br>
> > > > Eliot Miranda uploaded a new version of System to project The Trunk:<br>
> > > > <a href="http://source.squeak.org/trunk/System-eem.835.mcz" rel="noreferrer" target="_blank">http://source.squeak.org/<wbr>trunk/System-eem.835.mcz</a><br>
> > > ><br>
> > > > ==================== Summary ====================<br>
> > > ><br>
> > > > Name: System-eem.835<br>
> > > > Author: eem<br>
> > > > Time: 5 July 2016, 6:13:25.980763 pm<br>
> > > > UUID: 44354df1-cecb-414c-a705-<wbr>daa84b7388dd<br>
> > > > Ancestors: System-eem.834<br>
> > > ><br>
> > > > Fix reading methods from DataStreams on Spur. Old code used pre-Spur<br>
> > numLits header format, and was not 64-bit aware.<br>
> > > ><br>
> > ><br>
> > > Does that mean that pre-Spur methods on datastreams cannot be read in<br>
> > Spur images?<br>
</span>> > > That would be a bummer???<br>
<span class="">> > ><br>
> > > It needs some kind of version stamp on the stream. Point me to some<br>
> > such and we can switch hit.<br>
> ><br>
> > There is none.<br>
> > I would say, we store the data in the format DataStream already know<br>
> > (which happens to be<br>
> > the Pre-Spur version) and adapt on read. That would ensure backward- and<br>
> > forward-compatibility:<br>
> ><br>
> > - We could still read CMs serialized in pre-spur.<br>
> > - We could also read Spur-CMs in pre-spur images.<br>
> ><br>
> > Ok. -- break --<br>
> > I just realized that what you changed was the read part. so no<br>
> > problem here. We could change the part to do things differently<br>
> > when running on spur or non-spur.<br>
> ><br>
><br>
> The thing is that the two header formats are incompatible. The old one<br>
> allows up to 2^9-1 literals, the new one up to 2^15-1. So staying with the<br>
> old format limits us. We need some kind of version stamp. Right now<br>
> DataStream and ImageSegment are extremely version-dependent and hence<br>
> restrictive formats. It would be good for someone to revisit them and try<br>
> and add some kind of versioning information, preferably supporting backward<br>
> compatibility.<br>
><br>
<br>
</span>While a bit ad-hoc, but we do have an image format number that is used<br>
for a similar purpose in the saved image files. Would that provide enough<br>
information to serve as a version stamp?<br></blockquote><div><br></div><div>Works for me.</div><div><br></div><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">The current known formats are maintained in package ImageFormat in the<br>
<a href="http://source.squeak.org/VMMaker" rel="noreferrer" target="_blank">http://source.squeak.org/<wbr>VMMaker</a> repository. It is small and independent<br>
of VMMaker, so we could consider moving it into the image if it is of<br>
more general utility.<br></blockquote><div><br></div><div>+1</div><div><br></div><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">Dave<br>
</blockquote></div><div><br></div><div class="gmail_signature" data-smartmail="gmail_signature"><div dir="ltr"><div><span style="font-size:small;border-collapse:separate"><div>_,,,^..^,,,_<br></div><div>best, Eliot</div></span></div></div></div>
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