Path: utzoo!attcan!uunet!wuarchive!usc!samsung!sdd.hp.com!hplabs!hpl-opus!hpcc05!hpcc01!hpccc!samc
From: samc@hpccc.HP.COM (Samuel Chau)
Newsgroups: comp.sys.hp
Subject: Re: more HP 110 questions
Message-ID: <5950022@hpccc.HP.COM>
Date: 19 Sep 90 02:08:05 GMT
References: <1990Sep13.200914.15950@portia.Stanford.EDU>
Organization: HP Corp Computing & Services
Lines: 27

>Two more questions:  First, is the memory on the 110 expandable beyond its
>present ~300k?  And second, where can I find some documentation for this beast?

Some three years ago I wrote an article on how to expand the HP110 memory
to 512K.  The article was published in an issue of The Portable Paper
(Hal Goldstein, editor).  The hardware changes involve removing over a 
dozen RAM chips from the HP110 memory PC board, replacing them with
higher density chips, and altering the decoding logic to support the
new RAM chips.  The hardware surgery took me about 8 hours with the
soldering iron (and desoldering station!)

The extra RAM is not usable as part of system memory.  Rather, I wrote
a RAM disk driver to give the HP110 an additional RAM disk, which can
be used to store frequently used programs.  If you decide to do the
mods I can send you the driver.

HP used to sell a service manual for the HP110, with part number 00090-90021.
Unfortunately it is no longer on the price list.  However, since I still
have my copy, I may be able to help you out if you have specific questions.

Disclaimer:  The above hardware modifications are NOT supported by Hewlett
	     Packard!

Sam Chau
HP Sunnyvale Personal Computer Division
samc@hpspcoi
(408) 720-3711