Why LispOS?
P. T. Withington
ptw@pobox.com
Fri, 27 Mar 1998 15:20:54 -0500
On 3/24/98 22:29, J. Han wrote:
>I bet many people who have never seen a live LispM would like
>to hear the answer, too. Old timers: it's an open invitation to
>tell your stories. Spill all the juicy details!
Just a short example of some things I miss from the LispM:
My LispM had been up for about 6 months. [Gee, that in itself is
something I miss. Not having to reboot because my X server leaks so
badly I'm lucky if I get 6 days of uptime.]
While I was away on vacation, someone used my machine which they knew had
a custom compiler loaded on it. This compiler was really just the LispM
compiler, but by rebinding a few hooks in the compiler, it generated
overlays for the boot ROM and front-end processor, which was really just
a tiny Lisp system running in a special mode of the Ivory chip.
Normally, the compilation environment was dumped to a database, which
allowed restoring and generating new overlays for an existing version of
the ROM. But I had been lazy and was working on a development version
for about 3 months without dumping out my state.
When I returned from vacation, I discovered that I had lost my state,
because this someone had reloaded an old environment to build an overlay.
It wasn't horrible, I could recompile all my sources to reconstruct the
environment, but then it occured to me:
I could just scroll back my output history, and look for *FEP-COMPILER*
(the variable the environment hung off of). In Genera, output in the
output history is not just text, it _is_ the object the text represents
(in CLOS terms, it is a presentation). So I just searched backwards for
*FEP-COMPILER*, looking for the first one that was not the current broken
value. I found it, did a (SETQ *FEP-COMPILER* <mouse-Left>) and was on
my way.
But, just for yuks, I noticed that I had only scrolled back about 2% of
my output history. I did a meta-< to go to the top of my history, and
looked at the date. Gee, my LispM has been "up" for nearly 6 months! I
spent a while scrolling forward, somewhat mesmerized by seeing a record
of everything I had been doing for the last 6 months. Even grabbed a
couple of tables I had drawn to stick into a status report.
My old hand office mate was amused. His machine had been up for a year
and a half (since the last power failure), but he did admit that he had
cleared his output history only 2 months ago...