HP28 Source, SYSEVAL's and Wickes

[Bill Wickes]

There have been a number of notes directed to me or about me, and
the general topics of HP-28 SYSEVALs, code listings, etc. So let me
see if I can respond to them all in a single note.

First of all, for those gentle readers who don't know who I am, I
was the software project manager for the HP-28C/S. Since coming
to HP in 1981, I have directed the following projects: HP-41
Extended I/O ROM, HP-75 I/O ROM, HP-71 Math and Forth/Assember
ROM (also the HP-41 Translator ROM, which I wrote myself as a
after-hours project), and the RPL operating system, which underlies
all current HP calculators with 2 or more display lines. In 1980, while
an assistant prof of physics at U. of Maryland, I wrote Synthetic
Programming on the HP-41C, which gave my name a lot of exposure in
the calculator user community, and led to my current employment.

It is important to note that Synthetic Programming was not in any
way HP supported during its writing, although they did review it
in HP Keynotes, which had a profound effect on the book's success.
Since I was not an HP employee, I was free to say anything I pleased
about the workings of the 41. Starting with the program code table
that was published in the PPC Journal, all that was described in the
book was derived by inference and experiment, without any access to
HP documentation.

Now, as an HP employee, I'm on the other side of the fence. I very
much admire outsiders' efforts to decipher the 28 system, and am
amazed at how much has been accomplished. I am sympathetic to requests
that we publish lists of SYSEVAL addresses or better yet the full
source code listings. There are two reasons why we haven't:

* Competitive reasons. We flatter ourselves that there are some ideas
and methods embodied in the 28 that our competitors might like to borrow.
By not publishing commented listings, we at least make them work for it.

* Support questions. We don't like to do things by half measures. We
did publish and support the HP-71 source code, which was a major effort.
To provide a comparable level of support for the 28 would be at least
twice that effort, which we simply don't have the staff to do. There
are about 9000 entry points in the 28 code, which requires 160 pages
just to index. The printed listings, reduced 4-to-1 and printed
double sided, are three inches thick. The only people here who are capable
of providing external support are lab engineers, who have their hands full
with other projects. 28 support is beyond the scope of our ordinary
Customer Support group.

The bottom line is that given the closed-box nature of the 28, it
is not a good product for HP to invest in low-level system support. The group
that reads these notes or is otherwise active in trying to push the 28
beyond the confines of the user-language is TINY compared to the
masses of users who are happy with the calculator as is. Our limited
active support resources are dedicated to the latter group. For those
of you that are more ambitious, we can't offer much more than sympathy
and encouragement.

So, have fun (it is fun--or you wouldn't be doing it), and don't be
too harsh in your thoughts about us here at HP. We're not trying
to make life difficult for you, it's just that we don't have much
time to help, either.

--Bill Wickes

[Dan Allen]

I for one would like to thank Bill for his work on all of the projects
that he has worked on. I have personally bought all of the various ROMs
and calculators that he has managed/work on and it is to our advantage
that HP has someone like Bill Wickes to help make great products.

I would also like to thank Alonzo Gariepy for posting the many pages of
information that he did about what he has discovered about the 28S. As
I read through it all in the past day or two, I have found myself
getting excited about the 28S like I got excited about Synthetic
Programming years ago when Bill Wickes wrote his book.

Let's all remember that such hacking is above all, FUN!

Dan Allen
HP Hacker