Alan Kay in the News
Cees de Groot
cg at cdegroot.com
Tue Apr 30 18:27:59 UTC 2002
Mark S. Miller <markm at caplet.com> said:
>So don't be shy about proposing Squeak-based or Parcels-based serialization
- SRP (State Replication Protocol) is a Smalltalk-platform-neutral
protocol with some nice properties, and is expressly meant to be usable
on platforms besides Smalltalk. Especially the data encoding is cool, but
apart from that it also has good support for class evolution, etcetera.
- Python has a neat serialization format that is based on some sort of
mini-language which has textual and binary representations, support for
custom formats and things like oid-replacements. Jim Fulton (Zope and
formerly Smalltalk) thinks it is usable from other languages as well. The
pickle.py module is less than 1000 lines of code.
- I wouldn't suggest XML - all the code doing the XML parsing is probably
too large for anything security-related.
- RMI would be doable in Smalltalk, I think; it's well specified and
the people behind RMI know what they were talking about so IMHO it's
an OK wire protocol. The multiplexing makes it quite efficient from a
resource-usage point of view. As you remark, Java serialization is a tad
complex, so this might be a big job.
- The Parcel format is VisualWorks specific, although it probably could be
ported (the problem is that the format has no formal specification AFAIK, so a
'port' would almost certainly mean having to read code from VisualWorks, which
brings you in muddy legal waters).
Even though I haven't followed the conversation on the E list on the necessity
of a text format, I dissent. I think that if you want a human to talk to a
running E instance through telnet you would better open a separate connection
with a minimal command language (maybe one that would allow you to specify an
object, step by step, and then you enter the "send" command).
>7) The format must be compatible with our security requirements. In
>particular, since E is only prepared to trust mobile E code, any need for
>executable code in the serialization format must be E code. Parcels as is
>fails this test of course.
In the context of heterogenous E implementations, the point of mobile code
becomes tricky, of course :-)
Cees de Groot http://www.cdegroot.com <cg at cdegroot.com>
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