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<TITLE>RE: ASN.1</TITLE>
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<P><FONT SIZE=1 FACE="Arial">-----Original Message-----</FONT>
<BR><B><FONT SIZE=1 FACE="Arial">From: </FONT></B> <FONT SIZE=1 FACE="Arial">Mike Spreitzer [SMTP:spreitze@parc.xerox.com]</FONT>
<BR><B><FONT SIZE=1 FACE="Arial">Sent: </FONT></B> <FONT SIZE=1 FACE="Arial">Friday, April 16, 1999 3:31 PM</FONT>
<BR><B><FONT SIZE=1 FACE="Arial">To: </FONT></B> <FONT SIZE=1 FACE="Arial">'Hutchison, Nigel'; xml-dev@ic.ac.uk</FONT>
<BR><B><FONT SIZE=1 FACE="Arial">Subject: </FONT></B> <FONT SIZE=1 FACE="Arial">RE: ASN.1</FONT>
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<P><FONT SIZE=2 FACE="Arial">Nigel Hutchison wrote: [[</FONT>
<BR><FONT SIZE=2 FACE="Arial">I would have thought that the best way of dealing with this issue is to use</FONT>
<BR><FONT SIZE=2 FACE="Arial">a "pleasant" syntax which was easy to process and implement another layer</FONT>
<BR><FONT SIZE=2 FACE="Arial">to compress the payload for transmission.</FONT>
<BR><FONT SIZE=2 FACE="Arial">]]</FONT>
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<P><FONT SIZE=2 FACE="Arial">Best in some contexts, but not all. The compression layer has runtime</FONT>
<BR><FONT SIZE=2 FACE="Arial">costs, in both code and memory footprint, and processing time. In some</FONT>
<BR><FONT SIZE=2 FACE="Arial">contexts (e.g., very resource-constrained items like cell phones and Palm</FONT>
<BR><FONT SIZE=2 FACE="Arial">Pilots), these costs can be significant.</FONT>
<BR><B><I><FONT COLOR="#0000FF" SIZE=2 FACE="Arial">[Nigel Hutchison]</FONT></I></B><I></I> <FONT COLOR="#0000FF" SIZE=2 FACE="Arial"> I had some experience recently in trying to devise a RPC XML DTD which was nice and compact. So I did also sorts of tricks with short tag names, repetition conventions etc etc. This had the effect of iincreasing the creation and parsing code significantly. I imagine that there is a considerable footprint and CPU penalty is this optimisation. II also found the prospect of testing and debugging this quite daunting.</FONT><B></B><B><I><FONT COLOR="#0000FF" SIZE=2 FACE="Arial"></FONT></I></B><I></I> <FONT COLOR="#0000FF" SIZE=2 FACE="Arial"> I then realised that when I send and receive XML documents via my analogue modem they are effectively compressed and decompressed by the hardware - so I was wasting my time (in that scenario at least). I would have thought that all cellphones would do compression and decompression when they send and receive data - is that not so? </FONT></P>
<P><FONT COLOR="#0000FF" SIZE=2 FACE="Arial"> I also found out that Mainframes have firmware supporting LZ compression these days.</FONT>
<BR><FONT COLOR="#0000FF" SIZE=2 FACE="Arial">Regards</FONT>
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<P><FONT COLOR="#0000FF" SIZE=2 FACE="Arial">Nigel Hutchison</FONT>
<BR><FONT SIZE=2 FACE="Arial"> Mike</FONT>
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