2 Feb
2017
2 Feb
'17
10:41 a.m.
From: Phil Blundell
I suspect it would probably not be all that hard to
write some
sort of preprocessor to convert such code
Really? Check out:
http://minnie.tuhs.org/cgi-bin/utree.pl?file=V6/usr/sys/ken/pipe.c
(Needless to say, none of the 'int *' things are actually pointers to
integers!)
In particular, what will lines like this:
sleep(ip+2, PPIPE);
do, depending on what 'ip' is declared as?
Noel
2 Feb
2 Feb
10:50 a.m.
On Feb 2, 2017, at 1:41 PM, Noel Chiappa <jnc at
mercury.lcs.mit.edu> wrote:
If "ip" is an int *, it would pass the address in ip plus 2 * 2. If ip is
actually the address of some struct, then hopefully that address offset by 4 is a
meaningful address. I'm guessing that the 2 in there represents
sizeof(foo)/sizeof(int). Right?
paul
From: Phil Blundell
I suspect it would probably not be all that hard
to write some
sort of preprocessor to convert such code
Really? Check out:
http://minnie.tuhs.org/cgi-bin/utree.pl?file=V6/usr/sys/ken/pipe.c
(Needless to say, none of the 'int *' things are actually pointers to
integers!)
In particular, what will lines like this:
sleep(ip+2, PPIPE);
do, depending on what 'ip' is declared as? 
11:15 a.m.
On Thu, Feb 2, 2017 at 11:50 AM, Paul Koning <paulkoning at comcast.net> wrote:
In this case it doesn't matter, so long as it is consistent. Some math
will happen and produce some number. The pointer is never
dereferenced.
sleep takes a sleep channel to sleep on. This channel is a unique
cookie that's implemented as the address of some struct (or some
offset into it in this case). Elsewhere in the code there's a
wakeup(ip+2) which will wakeup the sleeper. So long as ip+2 is the
same both places, we're good. Well, and so long as nothing else
accidentally evaluates to this same value.
This scheme is still used in at least modern BSDs, though it has grown
a bazillion variants.
Warner
On Feb 2, 2017, at 1:41 PM, Noel Chiappa <jnc
at mercury.lcs.mit.edu> wrote:
If "ip" is an int *, it would pass the address in ip plus 2 * 2. If ip is
actually the address of some struct, then hopefully that address offset by 4 is a
meaningful address. I'm guessing that the 2 in there represents
sizeof(foo)/sizeof(int). Right? From: Phil Blundell
I suspect it would probably not be all that hard
to write some
sort of preprocessor to convert such code
Really? Check out:
http://minnie.tuhs.org/cgi-bin/utree.pl?file=V6/usr/sys/ken/pipe.c
(Needless to say, none of the 'int *' things are actually pointers to
integers!)
In particular, what will lines like this:
sleep(ip+2, PPIPE);
do, depending on what 'ip' is declared as? 
11:15 a.m.
On 2/2/2017 10:50 AM, Paul Koning wrote:
The listings I've read of early unix have assembly files, mixed c +
assembly, and in this case ip is
register *ip;
so things get to be quite a lot of fun. BTW I recall seeing assembly in
the compiler phases as well as the system code, so things require a lot
of the code between the assembly interface and the C to line up. Not
sure if gcc does that, or if the conventions between early unix and gcc
would line up or not.
There are also wake calls as well with ip+1 as a parameter, FWIW. I've
not gone hunting to what those calls do. I'd need to read the sleep and
wake code, which may be assembly. More useful parts of the puzzle to know.
thanks
Jim
On Feb 2,
2017, at 1:41 PM, Noel Chiappa <jnc at mercury.lcs.mit.edu> wrote:
If "ip" is an int *,
it would pass the address in ip plus 2 * 2. If ip is actually the address of some struct,
then hopefully that address offset by 4 is a meaningful address. I'm guessing that
the 2 in there represents sizeof(foo)/sizeof(int). Right?
paul From: Phil Blundell
I suspect it would probably not be all that hard to write some
sort of preprocessor to convert such code
Really? Check out:
http://minnie.tuhs.org/cgi-bin/utree.pl?file=V6/usr/sys/ken/pipe.c
(Needless to say, none of the 'int *' things are actually pointers to
integers!)
In particular, what will lines like this:
sleep(ip+2, PPIPE);
do, depending on what 'ip' is declared as? 
11:32 a.m.
All this talk about compatibility...was there ever UNIX made for the PDP
11/40 and RL02, or was it only run on RK05? Wouldn't all of the C and wake
calls, etc issues have been solved then? Why is this an issue now? I am
largely ignorant to the details but from 20000 feet it would seem like this
would have been taken care of long ago. No need for pre-processing code,
etc. Please educate me if I am wrong, just curious.
Bill Degnan
11:36 a.m.
DEC V7m comes to mind.
On 2/2/17 11:32 AM, william degnan wrote:
All this talk about compatibility...was there ever
UNIX made for the PDP
11/40 and RL02, or was it only run on RK05? Wouldn't all of the C and wake
calls, etc issues have been solved then? Why is this an issue now? I am
largely ignorant to the details but from 20000 feet it would seem like this
would have been taken care of long ago. No need for pre-processing code,
etc. Please educate me if I am wrong, just curious.
Bill Degnan
11:38 a.m.
On 2/2/17 11:32 AM, william degnan wrote:
On Thu, Feb 2, 2017 at 2:36 PM, Al Kossow <aek at bitsavers.org> wrote:
All this talk about compatibility...was there
ever UNIX made for the PDP
11/40 and RL02, or was it only run on RK05? Wouldn't all of the C and
wake
calls, etc issues have been solved then? Why is
this an issue now? I am
largely ignorant to the details but from 20000 feet it would seem like
this
would have been taken care of long ago. No need
for pre-processing code,
etc. Please educate me if I am wrong, just curious.
Bill Degnan
DEC V7m comes to mind.
Yes, but in 1974 that was not an option. I guess the 74-77 version of UNIX
that would have been installed on a PDP 11/40 would have been made for RK05
drives. It would prob be worth the effort to find a version of UNIX 6 for
that media and port to RL02, rather than take a vanilla UNIX 6 and try to
make it work on RL02's and re-solve all of the problems that have already
been solved for the RK05 version. AND the RL02 is larger so moving a
multi-disk UNIX for RK05 disks/partition would not be confined by space.
b
11:40 a.m.
On Thu, Feb 2, 2017 at 7:38 PM, william degnan <billdegnan at gmail.com> wrote:
I am just wondering where on earth you'd find an RL02 in 1974.
-tony
On 2/2/17 11:32 AM, william degnan wrote:
On Thu, Feb 2, 2017 at 2:36 PM, Al Kossow <aek at bitsavers.org> wrote:
All this talk about compatibility...was there
ever UNIX made for the PDP
11/40 and RL02, or was it only run on RK05? Wouldn't all of the C and
wake
calls, etc issues have been solved then? Why is
this an issue now? I am
largely ignorant to the details but from 20000 feet it would seem like
this
would have been taken care of long ago. No need
for pre-processing code,
etc. Please educate me if I am wrong, just curious.
Bill Degnan
DEC V7m comes to mind.
Yes, but in 1974 that was not an option. I guess the 74-77 version of UNIX
11:49 a.m.
On Thu, Feb 2, 2017 at 2:40 PM, Tony Duell <ard.p850ug1 at gmail.com> wrote:
On Thu, Feb 2, 2017 at 7:38 PM, william degnan
<billdegnan at gmail.com>
wrote:
On Thu, Feb 2, 2017 at 2:36 PM, Al Kossow <aek at bitsavers.org> wrote:
UNIX
I am just wondering where on earth you'd find an RL02 in 1974.
-tony
You wouldn't ... so what I am saying is the issues associated with getting
UNIX running on a PDP 11/40 would have been addressed on the RK05 version,
a drive that was available then. Further, it'd be easier in my opinion to
port *that* version, the RK05 version to RL02 rather than fix a vanilla
UNIX 6 and port that to RL02.
b
>
>
> On 2/2/17 11:32 AM, william degnan wrote:
> > All this talk about compatibility...was there ever UNIX made for the
PDP
> > 11/40 and RL02, or was it only run on
RK05? Wouldn't all of the C and
> wake
> > calls, etc issues have been solved then? Why is this an issue now?
I am
> > largely ignorant to the details but from
20000 feet it would seem like
> this
> > would have been taken care of long ago. No need for pre-processing
code,
etc. Please educate me if I am wrong, just curious.
Bill Degnan
DEC V7m comes to mind.
Yes, but in 1974 that was not an option. I guess the 74-77 version of
11:53 a.m.
On 2/2/2017 11:40 AM, Tony Duell wrote:
On Thu, Feb 2, 2017 at 7:38 PM, william degnan
<billdegnan at gmail.com> wrote:
I am
just wondering where on earth you'd find an RL02 in 1974.
-tony
Western Dynex had 2.5mb removable over 2.5mb in 71.
https://archive.org/details/bitsavers_westernDyntionManualRevPOct78_13256055
Last version at link above, model 6000 is essentially an RL02. Came in
12, 18 and 24 sector (strapable). I think it could be hooked up to DEC
as the interface was pretty much the same.
thanks
Jim
On 2/2/17 11:32 AM, william degnan wrote:
On Thu, Feb 2, 2017 at 2:36 PM, Al Kossow <aek at bitsavers.org>
wrote:
All this talk about compatibility...was there
ever UNIX made for the PDP
11/40 and RL02, or was it only run on RK05? Wouldn't all of the C and
wake
calls, etc issues have been solved then? Why is
this an issue now? I am
largely ignorant to the details but from 20000 feet it would seem like
this
would have been taken care of long ago. No need
for pre-processing code,
etc. Please educate me if I am wrong, just curious.
Bill Degnan
DEC V7m comes to mind.
Yes, but in 1974 that was not an option. I guess the 74-77 version of UNIX 
11:55 a.m.
On Feb 2, 2017, at 11:38 AM, william degnan
<billdegnan at gmail.com> wrote:
My first exposure to Unix was in 1977. We were running v6 on a *new*
PDP-11/34 with 4 RK05 drives. At time time DZ11?s were in short supply so
we (my room mate and I) built a z80 terminal concentrator so that we could
run 16 terminals off of the 11/34. I wrote the code on the z80 and he wrote
the Unix driver. We ended up re-working the protocol several times because
we kept loosing control packets. It wasn?t until later that we discovered that
the DL11 were were using to communicate with the z80 would not stay in
8-bit mode?we replaced the DL11 and everything was solid.
TTFN - Guy
On 2/2/17 11:32 AM, william degnan wrote:
On Thu, Feb 2, 2017 at 2:36 PM, Al Kossow <aek at bitsavers.org> wrote:
All this talk about compatibility...was there
ever UNIX made for the PDP
11/40 and RL02, or was it only run on RK05? Wouldn't all of the C and
wake
calls, etc issues have been solved then? Why is
this an issue now? I am
largely ignorant to the details but from 20000 feet it would seem like
this
would have been taken care of long ago. No need
for pre-processing code,
etc. Please educate me if I am wrong, just curious.
Bill Degnan
DEC V7m comes to mind.
Yes, but in 1974 that was not an option. I guess the 74-77 version of UNIX
that would have been installed on a PDP 11/40 would have been made for RK05
drives. It would prob be worth the effort to find a version of UNIX 6 for
that media and port to RL02, rather than take a vanilla UNIX 6 and try to
make it work on RL02's and re-solve all of the problems that have already
been solved for the RK05 version. AND the RL02 is larger so moving a
multi-disk UNIX for RK05 disks/partition would not be confined by space. 
11:56 a.m.
On 2/2/17 2:32 PM, william degnan wrote:
All this talk about compatibility...was there ever
UNIX made for the PDP
11/40 and RL02, or was it only run on RK05? Wouldn't all of the C and wake
calls, etc issues have been solved then? Why is this an issue now? I am
largely ignorant to the details but from 20000 feet it would seem like this
would have been taken care of long ago. No need for pre-processing code,
etc. Please educate me if I am wrong, just curious.
Bill Degnan
for laughs I wandered over to:
http://ftp.math.utah.edu/pub/mirrors/minnie.tuhs.org/PDP-11/Boot_Images/
To see if the copy of V6 on RL02 is still there.... yep it is. and it
runs on a 11/23 just fine
as thanks to someone I have a copy on RL02 that I boot from time to time.
Seems the problem is solved. If memory serves it cannot use more than
256K even if the
machine is Q22.
Allison
2:13 p.m.
On Thu, Feb 2, 2017 at 2:56 PM, allison <ajp166 at verizon.net> wrote:
On 2/2/17 2:32 PM, william degnan wrote:
Thanks. At this point, with a bad EIS board, there's not much I can do,
but I can use this in simH, and read up and get educated.
Bill
All this talk about compatibility...was there
ever UNIX made for the PDP
11/40 and RL02, or was it only run on RK05? Wouldn't all of the C and
wake
calls, etc issues have been solved then? Why is this an issue now? I am
largely ignorant to the details but from 20000 feet it would seem like
this
would have been taken care of long ago. No need for pre-processing code,
etc. Please educate me if I am wrong, just curious.
Bill Degnan
for laughs I wandered over to:
http://ftp.math.utah.edu/pub/mirrors/minnie.tuhs.org/PDP-11/Boot_Images/
To see if the copy of V6 on RL02 is still there.... yep it is. and it
runs on a 11/23 just fine
as thanks to someone I have a copy on RL02 that I boot from time to time.
Seems the problem is solved. If memory serves it cannot use more than
256K even if the
machine is Q22.
Allison
2661
days inactive
2661
days old
12 comments
9 participants
participants (9)
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aek＠bitsavers.org -
ajp166＠verizon.net -
ard.p850ug1＠gmail.com -
billdegnan＠gmail.com -
ggs＠shiresoft.com -
imp＠bsdimp.com -
jnc＠mercury.lcs.mit.edu -
jwsmail＠jwsss.com -
paulkoning＠comcast.net