Date   : Wed, 07 Oct 1987 13:04:47 EDT
From   : <SAGE@LL.ARPA>
Subject: Manual vs Autoinstall ZCPR3

   I received the following question from Ken Wallewein.  Since the answer
may be of general interest, I am posting it to the entire list.
 
::   I was wondering about ZCOM. I've read that it's the low-class way to
:: go, that it uses up a lot of TPA, and that real hackers will do a
:: proper implementation. What's the scoop? It there really a penalty for
:: using ZCOM?
 
   I wonder where you read that ZCOM is a low-class way to go.  It's true
that it does not give a programmer a chance to display his skills at
modifying his BIOS and reconfiguring the operating system.  It is also true
that ZCOM offered less flexibility in the definition of the system (it had
RCP, FCP, NDR, and IOP buffers of a size determined by Joe Wright).  And
finally, ZCOM does cost an extra 0.5K of TPA compared to the same system
installed manually (assuming the manual system has cleverly written BIOS
modifications).
 
   However, we have a new version of ZCOM in the works, called NZCOM, that,
in my opinion, will make manually installed systems undesirable and
obsolete.  Right now, for example, I am having trouble getting WordStar 4 to
run on my system (manual installation) because there is not enough TPA.  If
I had ZCOM, I could just drop out of ZCOM and run WS4 under CP/M.  Under the
new NZCOM, one will be able to create complete Z-System configurations
dynamically, on-the-fly!  When you want to run WS4, an alias script justs
commands the system to drop any RCP and IOP and to go to a small FCP while
WS4 is running.  This might give you back up to 4K of TPA.  When WS4 is
finished, the alias could automatically restore the original, more complete
Z-System.
 
   When you want to make use of an IOP, like NuKey, for example, you invoke
a NuKey loading alias.  It checks to see if the current system supports an
IOP of the necessary size.  If not, it commands the system to allocate space
for and initialize an IOP.  It then loads NuKey, and away you go!  When
you're done, you can tell the system to drop the IOP if you want to recover
the 1.5K of TPA.
 
   This kind of freedom will cost only 0.25K of TPA in any given system
compared to an equivalent manually installed system.  That is a VERY small
penalty to pay for the freedom gained.  It is even possible that because one
does not need any ZCPR3 code in the BIOS coldboot routine, the BIOS might
become shorter, and the net penalty might even be zero.
 
   In summary then, the autoinstall approach is not at all a low-class way
to get a Z-System, and with NZCOM it will become the smartest way to do it,
because it will give by far the most powerful implementation.  No more will
you face the dilemma of whether the features of ZCPR3 are worth the cost of
the TPA lost.  You will be able to trade off features and TPA on a command-
by-command or task-by-task basis.
 
-- Jay Sage