[pdftex] Re: TeX output as Java graphic

[Jeffrey McArthur]

On Sat, 6 Dec 2003 23:38:59 +0100 (MET), you wrote:

>Is the extra speed of classical emtex due to the absence of
>the source code modifications needed for a *high capacity* TeX
>implementation? Or is it due to assembly language optimizations
>by E. Mattes?

My numbers were based on 386 and 486.  Not sure if that still holds true
with the Pentium I, II, III, IV.  The speed was(is?) because the x86
architecture was designed with the Pascal memory model: code, data, stack,
and heap.  That is why there are the CS, DS, SS, and ES segment pointers.
The small version of TeX had only 64K of data, stack, and heap.  TeX
actually ran in only 256K of RAM.  In that small of a memory space the
segment registers did not need to change. That made the code smaller and
much faster.  Changing the segment register was slow.

>To put TeX's speed in perspective, (Plain) TeX easily runs
>10 times faster that the browsers I use.

Browsers seem to be getting slower and slower.

>And Pascal? Incidentally, the Java implementation of TeX was
>once clocked 140 times slower than the C
>implementation.

I remember back in 1999 at the TeX conference on TeX in Vancouver some
discussion about TeX and Java.