[comp.sys.ibm.pc] looz-execute?

bobmon@iuvax.cs.indiana.edu (RAMontante) (04/29/88)

cjeffery@arizona.edu (Clinton Jeffery) writes:
>
>Does ZOO compress?  Then can LOOZ execute a 373K .EXE file directly from
>the compressed .ZOO file?  Inquiring minds want to know!
>ZOO is free, and everyone who wants it has it...

The looz documentation states that the executable file must be not more
than 65535 bytes.

Does anyone know if/where MSDOS source for looz and zoo might be?  This might
be a nice limit to eliminate.
....
"It happens sometimes...people explode...natural causes."

dhesi@bsu-cs.UUCP (Rahul Dhesi) (04/30/88)

In article <8322@iuvax.cs.indiana.edu> bobmon@iuvax.UUCP (RAMontante) writes:
>>...Then can LOOZ execute a 373K .EXE file directly from
>>the compressed .ZOO file?
>The looz documentation states that the executable file must be not more
>than 65535 bytes.
>
>Does anyone know if/where MSDOS source for looz and zoo might be?

Typically, you don't save much time or space by keeping very large
programs in compressed form, since uncompression then takes a while.
So it seemed likely that the direct extract/execute feature of looz
would only be useful for small programs.

Having looz release all memory it took before transferring control to
the extracted program requires quite a bit of memory gymnastics and
multiple relocations.  (It was an interesting debugging excercise.)
Restricting the extracted program to a 64 K segment kept things
simpler.  You could blame the 8086 architecture that this was so.

The source for MSDOS zoo isn't published yet, but will be, as soon as
zoo 2.0 for UNIX gets published.

I'm inclined to keep the looz source secret though, since it's fun
having the only archiver in the world that does the direct
uncompress/execute with no memory penalty, and publishing source might
cause loss of this distinction. :-)
-- 
Rahul Dhesi         UUCP:  <backbones>!{iuvax,pur-ee,uunet}!bsu-cs!dhesi

cjeffery@arizona.edu (Clinton Jeffery) (04/30/88)

From article <2805@bsu-cs.UUCP>, by dhesi@bsu-cs.UUCP (Rahul Dhesi):
> So it seemed likely that the direct extract/execute feature of looz
> would only be useful for small programs....[8086 segment gripes ommitted]
> I'm inclined to keep the looz source secret though...[songs of praise...]
> publishing source might cause loss of this distinction. :-)

1) Well, gee, it turns out direct compress/execute of large
   files has interesting applications after all, doesn't it?
2) How serious is this smiley?  It IS your program, but...
3) All this points to an obvious question: will some OTHER archiver execute
   a 373K file out of an archive?  Even if it doesn't release its memory
   before doing so, 640K 2-disk pc users might be able to run PCNethack.
   There are a lot of 640K 2-disk pc users.  I am *NOT* one of them!!!
-- 
| Clint Jeffery, University of Arizona Department of Computer Science
| cjeffery@arizona.edu -or- {ihnp4 noao}!arizona!cjeffery
--