Path: utzoo!utgpu!news-server.csri.toronto.edu!rpi!zaphod.mps.ohio-state.edu!sdd.hp.com!hp-pcd!hpcvra.cv.hp.com!everett
From: everett@hpcvra.cv.hp.com. (Everett Kaser)
Newsgroups: comp.sys.handhelds
Subject: Re: HP95lx
Message-ID: <25590158@hpcvra.cv.hp.com.>
Date: 2 May 91 22:28:49 GMT
References: <7w4a21w163w@ireta.cynic.wimsey.bc.ca>
Organization: Hewlett-Packard Co., Corvallis, OR, USA
Lines: 31


 (Rob Prior) writes...
>Let's say I load the same program onto a RAM card for my hp95lx (or
>portfolio).  When I run the program, will it run directly from the
>card, or will it duplicate itself into the main RAM?

>Rob

For most people and situations, the answer on the HP 95LX is yes, you'll have
two copies, one on the RAM disk and one that's being executed in system
memory.  Virtually all of the software that built into the 95 executes in
place (XIP by PCMCIA terminology), and the design of the product allows for
and supports the addition of plug-in ROM cards with XIP code.  However, it's
not trivial and straight-forward to generate XIP code, as there's restrictions
and rules to be followed.  The problem with a RAM disk XIP program is that
there's no guarantee that all of the sectors containing the program exist in
one contiguous block (DOS likes to sling clusters all over the place).  This
makes it difficult for the CPU to execute the code (he says, dry humor dripping
from his keyboard).

The PCMCIA XIP standards committee has been working for well over a year on
the issue of XIP "standards" and has yet to come close to anything like an
agreed upon proposal.  Movement appears to be on the horizon, however, and 
there is hope that MAYBE 1992 will actually see a published XIP standard that
all manufactures can follow, allowing for the possibility of software vendors
to generate a single ROM card of their product that can be run in a number
of different hardware vendors machines.

Everett Kaser                   Hewlett-Packard Company
...hplabs!hp-pcd!everett        work: (503) 750-3569   Corvallis, Oregon
everett%hpcvra@hplabs.hp.com    home: (503) 928-5259   Albany, Oregon