Re: jpeg viewers

[pubpc1@library.ucla.edu]

spec@vax2.concordia.ca (Mitchell Spector) wrote:
>Even the Apple IIgs is heavily
>bogged down trying to decode a JPEG image and takes what seems like ages
>(my 15 MHz accelerator helps, but it is still relatively unbearable, the
>reason I now use my PC exclusively for handling that format). I shutter
>to think how long it would take a 1 MHz Apple IIe to decompress a JPEG
>or convert it into another format like GIF.
>
>Mitchell Spector
>spec@vax2.concordia.ca

The 15MHz 65C816, although fast, is still lacking an FPU.  I noticed
that when comparing a 13.75MHz '816 in a GS against a 25MHz '486 in
a PC, in word processing and page layout applications, the GS is
faster.  In graphics manipulation and spreadsheets, the GS falls
behind.  The FPU in the '486 is a tremendous advantage in such tasks.

To be fair, Mac and PC computers that lack FPUs (for example, '286
machines or 68000 based Macs) are also slow at such tasks, as are
crippled versions of the '386 and '486 that some PC makers sold.

The way someone once explained it to me is this.  For a CPU chip
without an FPU to do, for example, division, it has to break everything
down into addition and subtraction operations.  In other words, it
must do long division (subtract, bring down the remainder, and repeat
at the next decimal place) like a human being would do with pencil
and paper.  With an FPU, the CPU is freed from doing this.  Thus,
what would take many operations now takes only one.

If you want to see the GS decode that JPEG in a jiffy, you have to
have a math coprocessor.  It would be fun to have a GS with a
Floating Point Engine or Number Cruncher card (68881 or 68882 FPU)
installed.  Too bad they weren't more widely available and cheaper.
Too bad the Zip GS and the Transwarp GS didn't have FPU sockets.

-Scott G.