LispOS on a 68000

Craig Lanning
Fri, 15 May 1998 16:04 -0400

    Date: Fri, 15 May 1998 14:18 EDT
    From: David Tillman <>

	I am curious, how did the old LispMs relate to the 68000, 68030,
	and 68040 speed wise?

	What type of processor, architecture, and amount of memory/storage?


A while back, I asked Symbolics what the processor speed was and the
answer that I got was that the XL1200 Ivory processor was running at 30
or 40 MHz.  (It took a high end Alpha workstation running OpenGenera to
match the performance of that XL1200.)

I understand that at one time Symbolics was looking into using a
modified PowerPC chip as an alternative to the Ivory chip.  It seems
that the instruction set for the PowerPC was such that running Lisp on
it would be easy.  The modification that Symbolics wanted was to have
tag bits added.

The Symbolics Ivory processor was(is) a custom chip specifically
designed to run Lisp.  (Reading its disassembled code is almost like
read Lisp.)  It used a stack based architecture (no registers), but had
enough on chip memory to store an entire stack frame (function call,
including local variables) which meant that each local variable was
effectively a register.

The XL1200 in my office, that I STILL use on a daily basis, has 8MW (40MB)
of physical memory and two SCSI disks (1.4GB and 1.9GB).