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...