Envelope-to: craig@sbc-85.com
Delivery-date: Thu, 09 Mar 2023 13:12:14 -0600
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From: SBC-85 <craig@sbc-85.com>
Mime-Version: 1.0 (1.0)
Subject: Re: TEA % ASM1
Message-Id: <0508F63C-FDAB-40EF-9209-3C9682CA62A5@sbc-85.com>
References: <141a0b96-c1ad-cb37-a09e-ecd3ef670d68@gmail.com>
In-Reply-To: <141a0b96-c1ad-cb37-a09e-ecd3ef670d68@gmail.com>
To: denverh <denverh2000@gmail.com>
Date: Thu, 9 Mar 2023 11:12:03 -0800

Hi Denver

I am putting together the story of your FDOS snd TEA in the bubble for a vid=
eo (after I get mine going)

what role did the  sbc actually play in this recovery effort?  You had alrea=
dy gotten the bubble and FDOS working on the explorer first didn=E2=80=99t y=
ou?=20

Was porting the file system and TEA pretty much a separate effort?   did the=
 SBC just act as an incentive to resurrect the explorer or was there s large=
r role?

Regards
Craig

> On Mar 8, 2023, at 4:37 PM, denverh <denverh2000@gmail.com> wrote:
>=20
> =EF=BB=BFcraig@sbc-85.com wrote:
>> Thanks Denver,
>>=20
>> the paper tape reading response sounds like a good idea.  I have often go=
tten into a stalemate with resident monitors that respond with ? asking for t=
he next command when I interpreted it as they didn't understand the last com=
mand.
> Hi Craig,
>=20
> There was something else I was going to mention, but forgot.  Both TEA and=
 ASM1 use FDOS functions via RST 2.  The Dunfield monitor uses a "base addre=
ss" to relocate the interrupt vectors, but it always initializes this to 000=
0 when it starts.  So if you have a copy of either program in RAM you can't s=
uccessfully run it from the monitor.  You have to do it from FDOS.  As an ex=
ample, suppose TEA is in RAM at 8000, starting from a reset:
>=20
> C> G 2000               (starts FDOS from monitor)
> -J 8000                 ( FDOS JUMP to 8000)
>=20
> INITIAL ADDRESS?        (TEA starts)
>=20
> That's what you would need to do if you were cross-assembling anything tha=
t used FDOS RST 2 functions: transfer to RAM, start FDOS, then try running t=
he program from there.  Decades ago this kind of complexity was pretty norma=
l.  There was a vacuum tube computer I had some very brief experience with s=
ome time in the late 60's.  A few years ago I read an article about an old c=
omputer that sounded like the one I remembered.  Further investigation prove=
d that it was the same, an LGP-30.  Now that machine had a truly complicated=
 startup procedure.  There's a video on youtube somewhere demonstrating one.=
  The CDC machines I first worked on were also complicated, and so were the m=
inicomputers I worked on later.  We're really spoiled these days, when all y=
ou need to do is turn on the power.
>=20
> Thanks,
>=20
> Denver
>=20