_DrawPicture

[shen@schemer.Jpl.Nasa.Gov (Sheldon Shen)]

On page 88 and 89 of Inside Macintosh V, an example is given
to spool a picture from disk.  In that example, QuickDraw
repeatedly calls GetPICTData, which in turn calls
FSRead(globalRef,longCount,dataPtr).

I assume that dataPtr is a pointer to the buffer and
longCount is the number of bytes transferred from the disk
to the buffer.  Therefore, if I increase longCount, I/O can
be reduced and drawing a picture can be expedited.  This
does not seem to work. Worse, when I set longCount to 1024,
the system simply crashes.

(There are two files, "mac-file-io.lisp" and
"picture-files.lisp", at cambridge.apple.com.  These files
implement the example on page 88 and 89 in MCL.  The
longCount used there is 10.)

How to speed up _DrawPicture by providing a larger buffer?

Thanks,

Shelodon Shen
(shen@granite.jpl.nasa.gov)