11 Jul
2022
11 Jul
'22
7:47 p.m.
Hello, and greetings!
I guess as this is my first post here, I should give some background on
what I have been working on. Last summer I spent a lot of time getting UNIX
V6 working on my PDP-11/23 system. It took a lot of tinkering with the
kernel and drivers to make it work in the way I wanted to, but in the end I
was left with a system that ran well enough to do some demonstrations at
VCFMW.
This year I want to do more stuff with 1970s era UNIX, but now with even
more technical restrictions. I have had a Heathkit H-11 (consumer grade
PDP-11/03) for a while now, and I have been looking for something
interesting to do with it. From my research, it seems like there were two
different UNIX variants that could run on a system like this. These
variants were LSX and MINI-UNIX. MINI-UNIX seems to require a decent
mass-storage device like a RK05 and some porting to work on an 11/03, while
LSX is designed to work on exactly the hardware specs that I have on hand.
So on to the actual issues I am having at the moment: I have put together a
SIMH instance to get the ball rolling in building a kernel that will boot
on my EIS-less 11/03, but I am having significant difficulty actually
getting the kernel to build. The first issue is that the C compiler will
randomly spit out a "0: Missing temp file" when attempting to compile
something. This is annoying, but circumventable by just running the same
command over and over until it works. The second issue, however, is much
more of a road block for me. I can't seem to get the kernel to actually
link together once everything is compiled. When the final "ld -X" is
executed, I always get the following errors:
"
Undefined:
_end
_edata
_decmch
"
(This is from the build script found in the "shlsx" file)
https://minnie.tuhs.org/cgi-bin/utree.pl?file=LSX/sys/shlsx
I am assuming that this is some sort of issue with the object file
orderings, but I simply do not know enough about V6 ld to properly debug
this issue. I am hoping that somebody here has already run into this issue,
and knows what I am doing wrong.
If I can get this working, I have a long laundry list of modifications and
experiments that I want to run with LSX, but as it stands, this is where I
am stuck at.
Thank you,
Gavin
11 Jul
11 Jul
8:01 p.m.
On Mon, Jul 11, 2022, 1:48 PM Gavin Tersteeg <gctersteeg(a)gmail.com> wrote:
Hello, and greetings!
I guess as this is my first post here, I should give some u background on
what I have been working on. Last summer I spent a lot of time getting UNIX
V6 working on my PDP-11/23 system. It took a lot of tinkering with the
kernel and drivers to make it work in the way I wanted to, but in the end I
was left with a system that ran well enough to do some demonstrations at
VCFMW.
This year I want to do more stuff with 1970s era UNIX, but now with even
more technical restrictions. I have had a Heathkit H-11 (consumer grade
PDP-11/03) for a while now, and I have been looking for something
interesting to do with it. From my research, it seems like there were two
different UNIX variants that could run on a system like this. These
variants were LSX and MINI-UNIX. MINI-UNIX seems to require a decent
mass-storage device like a RK05 and some porting to work on an 11/03, while
LSX is designed to work on exactly the hardware specs that I have on hand.
So on to the actual issues I am having at the moment: I have put together
a SIMH instance to get the ball rolling in building a kernel that will boot
on my EIS-less 11/03, but I am having significant difficulty actually
getting the kernel to build. The first issue is that the C compiler will
randomly spit out a "0: Missing temp file" when attempting to compile
something. This is annoying, but circumventable by just running the same
command over and over until it works. The second issue, however, is much
more of a road block for me. I can't seem to get the kernel to actually
link together once everything is compiled. When the final "ld -X" is
executed, I always get the following errors:
"
Undefined:
_end
_edata
_decmch
"
(This is from the build script found in the "shlsx" file)
https://minnie.tuhs.org/cgi-bin/utree.pl?file=LSX/sys/shlsx
I am assuming that this is some sort of issue with the object file
orderings, but I simply do not know enough about V6 ld to properly debug
this issue. I am hoping that somebody here has already run into this issue,
and knows what I am doing wrong.
_end is the end of the text segment. _edata same for the data. You can
create these two by just creating a file that defines them as symbols = .
And global. And link that file last. Though crt is supposed to have that.
_decmch is likely in m.s so maybe that's not included. Iirc it should be
next to last...
You might already have files with these symbols... nm is your friend here...
Warner
If I can get this working, I have a long laundry list of modifications and
experiments that I want to run with LSX, but as it
stands, this is where I
am stuck at.
Thank you,
Gavin
8:26 p.m.
@Warner Losh <imp(a)bsdimp.com>
On Mon, Jul 11, 2022 at 4:03 PM Warner Losh <imp(a)bsdimp.com> wrote:
_end is the end of the text segment. _edata same for the data. You can
create these two by just creating a file that defines them as symbols = .
And global. And link that file last. Though crt is supposed to have that.
Hmmm -- I might have miss remembered this... but I'm pretty sure the way
ld(1) worked is that it supplied _edata, _etext, and _end automagically by
ld(1) IIF, there are no other undefined symbols. Adding them into a file is
probably not going to get what you want.
_decmch is likely in m.s so maybe that's not included. Iirc it should be
next to last...
My bet is this key to the whole issue he is having. If Gavin can figures
out what gives WRT _decmch, I bet it links.
@Gavin Tersteeg < gctersteeg(a)gmail.com> -- I would trust Warner's memory
more than mine since he tries to keep 2.9BSD alive, but he knows I go back
to V5 and the early/mid 70s; but bits in my memory have decayed over the
years. Suggestion, take a quick peek in the sources to ld.c and look for
it hard coding the check for those three symbols. They will look up as
undefined originally, then latter get set to values only if there are no
other UNDEFINED symbols.
ᐧ
8:30 p.m.
On Mon, Jul 11, 2022 at 2:27 PM Clem Cole <clemc(a)ccc.com> wrote:
That's the area I'd try first... But I'd expect both data and bss symbols
to be scattered in many of the other files though... It may be something as
simple as an empty .o file from those compiler runs that failed...
@Warner Losh <imp(a)bsdimp.com>
On Mon, Jul 11, 2022 at 4:03 PM Warner Losh <imp(a)bsdimp.com> wrote:
Oh right, _etext, _edata and _end are supposed to be linker creatures
(created by the linker), but I can't recall when the linker started doing
that...
_end is the end of the text segment. _edata same for the data. You can
create these two by just creating a file that defines them as symbols = .
And global. And link that file last. Though crt is supposed to have that.
Hmmm -- I might have miss remembered this... but I'm pretty sure the way
ld(1) worked is that it supplied _edata, _etext, and _end automagically
by ld(1) IIF, there are no other undefined symbols. Adding them into a file
is probably not going to get what you want.
_decmch is likely in m.s so maybe that's not
included. Iirc it should be
next to last...
My bet is this key to the whole issue he is having. If Gavin can figures
out what gives WRT _decmch, I bet it links.
@Gavin Tersteeg <+gctersteeg(a)gmail.com> -- I
would trust Warner's memory
more than mine since he tries to keep 2.9BSD alive, but he knows I go back
to V5 and the early/mid 70s; but bits in my memory have decayed over the
years. Suggestion, take a quick peek in the sources to ld.c and look for
it hard coding the check for those three symbols. They will look up as
undefined originally, then latter get set to values only if there are no
other UNDEFINED symbols.
2.11BSD, but who's counting :)
Warner
ᐧ
8:37 p.m.
A quick google for _decmch found:
https://www.tuhs.org/cgi-bin/utree.pl?file=LSX/sys/low.s
.....
.if DEC
.if EIS-1
.globl _decmch
rxcs = 177170
rxdb = 177172
_decmch:
mov r2,-(sp)
mov $rxdb,r1
mov 4(sp),r0
asl r0
add 4(sp),r0
clr r2
.....
1026
days inactive
1026
days old
4 comments
4 participants
participants (4)
-
Clem Cole -
Gavin Tersteeg -
Phil Budne -
Warner Losh