Re: Is The M9312 Boot Module Essential?

[Ethan Dicks via cctalk]

On Sat, Feb 19, 2022 at 4:40 PM Fritz Mueller via cctalk
 wrote:
> > On Feb 19, 2022, at 12:11 PM, Fritz Mueller  wrote:
> A few additional details, in case it is helpful:
>
> IIRC, the 11/34 doesn’t have SACK timeout implemented in the CPU cards (the 
> /34A did add this, however.)  So without an M9302 on the far end of the bus, 
> the CPU could hang in a situation with an unacknowledged grant (which I think 
> would be somewhat rare, but possible).  I believe it is possible to boot an 
> 11/34 at least as far as a ROM boot monitor with a non-SACK (M930 or such) 
> terminator on the far side.

Thank you for bringing this up - I have a stack of KD11-E and KD11-EA
board sets (and MOS memory and all the other things).  I've been
trying to get them to work in a BA11-L that started off life as a
PDP-11/04 and I've swapped the DD11-DK for a DD11-P backplane but I
wasn't having any luck getting things to run.  I did find a bad 7402
in the limited function front panel but that was the only fault I
found (so far).  I've checked the grant chain but what I haven't done
is ensure I have the right combo of terminators and CPU cards.  I'm
used to configuring machines, but I honestly forget if the experiences
I had in the 80s were 11/34 or 11/34A.  This gives me something to go
back and check.

I was about ready to start hacking on an M9302 to sniff out the SACK
logic.  Now I'll go back and check the docs and make sure I'm putting
together a set of cards that's going to want to play nice with each
other.

I have plenty of dual-height grant cards.  I'm definitely _not_ having
issues with NPR.

Thanks!

-ethan

Re: Is The M9312 Boot Module Essential?

[Fritz Mueller via cctalk]

> On Feb 19, 2022, at 10:51 AM, Noel Chiappa via cctalk  
> wrote:
> The -11/34 (not the /34A) has something unusual for grant timeouts, but I
> forget the details. I'll look it up.

> On Feb 19, 2022, at 12:11 PM, Fritz Mueller  wrote:
> I just did an 11/34 restoration last year, so this is fresh in mind — I think 
> you are thinking of the M9302, Noel: a far-side terminator card with 
> integrated SACK turnaround?

A few additional details, in case it is helpful:

IIRC, the 11/34 doesn’t have SACK timeout implemented in the CPU cards (the 
/34A did add this, however.)  So without an M9302 on the far end of the bus, 
the CPU could hang in a situation with an unacknowledged grant (which I think 
would be somewhat rare, but possible).  I believe it is possible to boot an 
11/34 at least as far as a ROM boot monitor with a non-SACK (M930 or such) 
terminator on the far side.

An 11/34 with a M9302 SACK terminator _will_ hang, though, with a broken grant 
chain — the floating grant will trigger the M9302 to continuously assert SACK 
locking the bus.  “Better” CPUs, which used SACK timeout instead of 
turn-around, were more robust this way.

Incidentally, I think the 11/34 was contemporaneous with, and usually found 
with, the slightly earlier M9301 ROM terminator on the near side, rather than 
the later M9312, though both should work fine.

cheers,
—FritzM.

Re: Is The M9312 Boot Module Essential?

[Bill Degnan via cctalk]

Here is how I used mine on a PDP 11/05.  Literally right now.
1.  Boot up the system and use the front panel to load 165020(8)
2.  Run from this address
3.  My system is set to communicate with a Teletype, so it comes to life
and prints the status of the CPU registers to the teletype
4.  I type in L 0 to load memory address 000(8)
5.  I have BASIC stored to load from this address, so the system sends
READY to the teletype and I can then run BASIC commands.

THe M9312 is a luxury, I could just as easily just loaded 000 from the
start and it would have initiated BASIC.

Bill

On Sat, Feb 19, 2022 at 3:11 PM Fritz Mueller via cctalk <
cctalk@classiccmp.org> wrote:

>
>
> > On Feb 19, 2022, at 10:51 AM, Noel Chiappa via cctalk <
> cctalk@classiccmp.org> wrote:
> > The -11/34 (not the /34A) has something unusual for grant timeouts, but I
> > forget the details. I'll look it up.
>
> I just did an 11/34 restoration last year, so this is fresh in mind — I
> think you are thinking of the M9302, Noel: a far-side terminator card with
> integrated SACK turnaround?
>
>—FritzM.
>
>
>

Re: Red Hat Linux 7.2 for Alpha

[Larkin Nickle via cctalk]

Try these:

https://mirror.rqsall.com/misc/rh-alpha/7.2/

Larkin

Re: Is The M9312 Boot Module Essential?

[Fritz Mueller via cctalk]

> On Feb 19, 2022, at 10:51 AM, Noel Chiappa via cctalk  
> wrote:
> The -11/34 (not the /34A) has something unusual for grant timeouts, but I
> forget the details. I'll look it up.

I just did an 11/34 restoration last year, so this is fresh in mind — I think 
you are thinking of the M9302, Noel: a far-side terminator card with integrated 
SACK turnaround?

   —FritzM.

Re: VAX9000 unearthed

[Paul Koning via cctalk]

> On Feb 19, 2022, at 1:28 PM, Jon Elson via cctalk  
> wrote:
> 
> On 2/18/22 21:43, ben via cctalk wrote:
>> 
>> The 70's was all low scale tech. I suspect it was the high speed/edge rates 
>> more the power that kept ECL from common use. Any other views on this topic. 
>> Ben, who only had access to RADIO SHACK in the 70's.
>> PS: Still grumbling about buying life time tubes at a big price,
>> just to see all tubes discontinued a year or two later.
> 
> Edge rates on pedestrian MECL 10K were not crazy fast.  Rise and fall of 
> about 1 ns, but the gate propagation delay was ALSO about 1 ns, so that was a 
> lot faster than TTL.  ECL was very easy to work with, crosstalk was not a 
> common issue.  But, you HAD to terminate any line over a foot, and better to 
> make it 6" to be sure.  And, the termination and pulldown resistors ate a LOT 
> of power!

I think there are a number of reasons why ECL was niche technology.  One is 
that TTL was fast enough for most applications.  Another is that more people 
knew TTL, and ECL requires (some) different design techniques.  Yet another is 
that higher levels of integration appeared in CMOS but not ECL.  Yet another is 
that ECL was expensive compared to the alternatives, partly because of the low 
integration and partly because of the low volume.

In the mid-1980s (I think) there was a very interesting project at DEC Western 
Research Lab to build a custom VSLI ECL processor chip.  A lot of amazing 
design was done for it.  One is power and cooling work; it was estimated to 
consume about 100 watts which in that day was utterly unheard of, by a 
substantial margin.  This was solved by a package with integral heat pipe.  
Another issue was the fact that ECL foundries each had their own design rules, 
and they were shutting down frequently.  So the CAD system needed to be able to 
let you specify a design where the fab rules were inputs to the layout 
algorithms.  The design took great advantage of ECL-specific logic capabilities 
like wire OR or stacked pass transistors.  I remember that the CAD system let 
the designer work at multiple levels in the same chip: at the rectangle level 
(for memory arrays), transistor level, gate level, and even write some 
constructs as programming language notations.  For example a 64-bit register 
could be specified as:

for (i = 0; i < 64; i++) { transistor-level schematic of a one-bit 
register }

Originally the idea was to use this for a 1 GHz Alpha; I think it ended up 
being a 1 GHz MIPS processor.  Possibly the project was killed before it quite 
finished.

That seems to have been one of the very few examples of ECL going beyond SSI.  
The physical possibility existed; the economics did not.

paul

Re: Is The M9312 Boot Module Essential?

[Noel Chiappa via cctalk]

> From: Jay Jaeger

> SACK turnaround capability so that the machine doesn't hang accessing
> an address that doesn't respond on the UNIBUS.

Umm, I think you're mixing up i) grant timeouts and ii) master-slave
timeouts.

All PDP-11 CPUs have master-slave timeout handling; after a short delay
(10usec or so) with no SSYN (UNIBUS) or BRPLY (QBUS), they resume processing,
and take an immediate trap. Most OS's (UNIX, for sure) use this when they are
sizing memory.

Grant timeouts are less well-documented. I think most CPUs deal with this (not
receiving a SACK 'fairly quickly' in response to a grant); I think they
basically just ignore t, and keep processing. (That is because there are
legitimate causes for not having a grant ackknowledged; e.g. if a device is
requesting an interrupt, and then just as the CPU sends out a grant, the
device is reset, the device won't respond to the grant, since it's no longer
trying to do an interrupt.)

The 'SACK turnaround' I think is only used with system health verification;
the system wants to make sure that the grant lines aren't broken anywhere.
(That's because _if_ a grant line is broken, devices downstream of the break
can no longer do interrupts, which generally _will_ hang the overall system,
when interrupts don't work as usual.) To do this, the CPU sends an
_un-requested_ grant out (on startup), and the SACK turnaround circuitry on
the terminator turns it around and sends it back to the CPU; when the CPU sees
that, it knows the grant line has no break.

It probably caused more problems than it caught, which is my guess as to why
no QBUS machine has/uses it.

The -11/34 (not the /34A) has something unusual for grant timeouts, but I
forget the details. I'll look it up.

Noel

Re: VAX9000 unearthed

[Jon Elson via cctalk]

On 2/18/22 21:43, ben via cctalk wrote:


The 70's was all low scale tech. I suspect it was the high 
speed/edge rates more the power that kept ECL from common 
use. Any other views on this topic. Ben, who only had 
access to RADIO SHACK in the 70's.
PS: Still grumbling about buying life time tubes at a big 
price,

just to see all tubes discontinued a year or two later.


Edge rates on pedestrian MECL 10K were not crazy fast.  Rise 
and fall of about 1 ns, but the gate propagation delay was 
ALSO about 1 ns, so that was a lot faster than TTL.  ECL was 
very easy to work with, crosstalk was not a common issue.  
But, you HAD to terminate any line over a foot, and better 
to make it 6" to be sure.  And, the termination and pulldown 
resistors ate a LOT of power!


Jon

Re: Is The M9312 Boot Module Essential?

[Chris Zach via cctalk]

Speaking of which, what does the console rom "DO"? Is it like the 
interactive boot from a pdp11/23+ or better where you can type in the 
device name, run little memory diagnostics and such?


I recall that with the real boot chips on a unibus 11/34 you could just 
jump to the location of the ROM and the CPU would start right up 
unprompted.


C


On 2/19/2022 3:29 AM, Bill Degnan via cctalk wrote:

You need some way to initialize the system to the peripheral that contains
the.OS media.  The m9312 is a general purpose co ntroller for that
purpose.  There are roms that install on the 9312 for almost any drive
hardware.  When you get a system that comes with an M9312, it will have the
appropriate peripheral Rom and console ROM installed from the factory.  The
M9312 also had a console ROM monitor to allow a person to attach a terminal
to enter bootstrap commands.

But yes the *function* provided by the m9312 is necessary.

Alternatively you can key in the bootstrap that tells your system how to
boot your OS and communicate with your boot device.

The m9312 is less useful without at least a console ROM

Where are you located?  Maybe someone nearby has in you could borrow just
to see what you need.
Bill.

On Sat, Feb 19, 2022, 2:12 AM Rob Jarratt via cctalk 
wrote:


I have a PDP-11/24. I have never got very far with it because of power
supply problems which I am hopeful will be resolved soon. Looking at the
technical manual, it describes an M9312 bootstrap/terminator module. The
machine did not come with one of these.



I am not sure how the machine could have been useful without it. It did
work
briefly before the PSU failed and I remember getting a console prompt. So,
is the M9312 essential to ever get this machine to boot up an operating
system?



Thanks



Rob

Re: DEC AXV11-C analog board

[Douglas Taylor via cctalk]

Put one together with back to back 9V batteries and a 5K pot.  Does 
exactly what I wanted.


The Data Translation board is set up for SE inputs and +/-10 V input range.
Was able to apply a series of DC voltages to the DT2762 board and record 
the A/D value using ODT (tedious, but works OK).
Using Octave (Linux) was able to convert the A/D 2's complement Octal 
numbers to decimal and plot input voltage versus A/D decimal value.  
Expected to see a nice clean linear plot.

The one DT2762 seemed to 'drop' bits, while the newer one seemed OK.

Next step is to capture a time varying signal and see if the A/D output 
follows the input correctly.  I'd like to use Macro-11 to manage the A/D 
board and Fortran to deal with the data.

What is the Fortran or F77 interface with Macro-11 routines?

Doug

On 2/13/2022 3:40 PM, Henk Gooijen via cctalk wrote:

Two batteries in series, using the “middle” as 0V reference.
The “+” is V+, the “-“ is V-.

Van: Douglas Taylor via cctalk
Verzonden: zondag 13 februari 2022 18:05
Aan: Jon Elson via cctalk
Onderwerp: Re: DEC AXV11-C analog board

Is it possible to construct a battery driven circuit that
will present both positive and negative voltages at the
input?  A bridge of some sort?

Doug

Free Stuff - Pleasanton, Calif.

[BILLY PETTIT via cctalk]

I'm downsizing.  Have to get rid of everything.  The driveway is filled systems 
test equipment, components, parts,  books, etc.  Several thousand TTL chips 
prototyping boards.  Come out and take what you.  Junk Bees will be here on 
Tuesday for what is left.

Call 925-998-9968 for directions.

Re: Is The M9312 Boot Module Essential?

[Chris Zach via cctalk]

The bit I am confused about is that I got a console prompt with just the CPU 
(M7133) and Unibus Map Module (M7134) installed. Presumably I could type in a 
bootstrap program from there?


Sure, that's just normal ODT if I recall. On my 5.25 inch 11/24 I have 
the CPU, MMU, a 1mb memory card, H7273s in the other slots on the way 
down, a RL11, a RX21, and a terminator (I forget if it's a 9302 or 9312).


C



  


Regards

  


Rob

  


From: Bill Degnan 
Sent: 19 February 2022 08:29
To: r...@jarratt.me.uk; Rob Jarratt ; General 
Discussion: On-Topic and Off-Topic Posts 
Subject: Re: Is The M9312 Boot Module Essential?

  


You need some way to initialize the system to the peripheral that contains 
the.OS media.  The m9312 is a general purpose co ntroller for that purpose.  
There are roms that install on the 9312 for almost any drive hardware.  When 
you get a system that comes with an M9312, it will have the appropriate 
peripheral Rom and console ROM installed from the factory.  The M9312 also had 
a console ROM monitor to allow a person to attach a terminal to enter bootstrap 
commands.

  


But yes the *function* provided by the m9312 is necessary.

  


Alternatively you can key in the bootstrap that tells your system how to boot 
your OS and communicate with your boot device.

  


The m9312 is less useful without at least a console ROM

  


Where are you located?  Maybe someone nearby has in you could borrow just to 
see what you need.

Bill.

  


On Sat, Feb 19, 2022, 2:12 AM Rob Jarratt via cctalk mailto:cctalk@classiccmp.org> > wrote:

I have a PDP-11/24. I have never got very far with it because of power
supply problems which I am hopeful will be resolved soon. Looking at the
technical manual, it describes an M9312 bootstrap/terminator module. The
machine did not come with one of these.



I am not sure how the machine could have been useful without it. It did work
briefly before the PSU failed and I remember getting a console prompt. So,
is the M9312 essential to ever get this machine to boot up an operating
system?



Thanks



Rob

Re: Is The M9312 Boot Module Essential?

[Jay Jaeger via cctalk]

My 11/24 does *not* have an M9312.  My UNIBUS out from the processor 
backplane goes to an RK611, and then to a VT11.  I have an M9301 at the 
end, in the VT11 UNIBUS OUT slot.  I didn't pull the map card, but I am 
99.% sure that my boot ROMs (RL11, RK611) are on my UNIBUS map card.


The UNIBUS MAP card has space for 5 ROMS: the console/diagnostic (which 
maybe isn't even socketed), and including the sockets 4 device ROMs.


You do want a terminator that provides a SACK turnaround capability so 
that the machine doesn't hang accessing an address that doesn't respond 
on the UNIBUS.  One option might be for you to build a UNIPROBE card, 
perhaps sans the LEDs to minimize the need for SMT devices to deal with.


I do have several spare M9312's and could sell you one - $50.  I can 
deal with shipping to the UK.  But I suspect you will be able to find 
someone from the UK on this list that has spare(s).


JRJ

On 2/19/2022 3:45 AM, Rob Jarratt via cctech wrote:

I saw this reply later than the previous one. It confirms that I don't
*need* it for booting, but it would be useful.

I suspect some of the other cards that were in the machine might do the
necessary termination stuff.

Thanks

Rob


-Original Message-
From: cctalk  On Behalf Of Noel Chiappa via
cctalk
Sent: 19 February 2022 09:18
To: cctalk@classiccmp.org
Cc: j...@mercury.lcs.mit.edu
Subject: Re: Is The M9312 Boot Module Essential?

 > From: Rob Jarratt

 > is the M9312 essential to ever get this machine to boot up an

operating

 > system?

Interesting question. I don't have my -11/24 running yet, so this reply is
theoretical, not tried in practice (and as we all know, the difference

between

theory and practice is even larger in practice than it is in theory), but

here

goes.

The M9312 basically provides two things: 1) UNIBUS termination, and 2)
boostrap ROM.

To further subdivide the former, it provides 1A) analog termination (i.e.

a

resistance at the end of a transmission line that prevents reflections of
signals passing down the otherwise un-terminated transmission lines of the
bus), 1B) pullups (so those transmission lines normally float at roughly

3V,

unless actively driven by one of the boards plugged into the bus) and 1C)
'SACK turnaround' (a start-up 'safety check' where an un-requested - and
thus 'un-grabbed' by any device - bus grant from the CPU on start-up is
'turned around' by the terminator; this verifies that the grant lines are

un-

broken between the CPU and the terminator - e.g. by someone forgetting to
plug in a grant jumper).

1A is not _absolutely_ necessary; this can be seen in small QBUS systems
(the QBUS is, at the analog level, sort of identical to the UNIBUS; this

an be

seen in the use of the same transceiver chips, such as 8641's, on both)

which

can get away without 1A in small configurations. Whether it's needed on

your

-11/24 is hard to predict, theoretically; the easiest thing is to just try

it and

see. Note: it may 'work' without it, but not be as _reliable_ as with it.

1B _is_ necessary, but can be provided anywhere on the bus; most
UNIBUS/QBUS CPUs have it built in, and so does the KDF11-U of the -11/24:
see pg.  of MP01028.

1C is required by _some_ UNIBUS CPUs (ISTR that the -11/04 won't run
without it), but the KDF11's in general don't; e.g. the -11/23 definitely

runs

without it. The KDF11-U might have outboard circuitry to require it, but

I'm

too lazy to grovel over the prints to see. Easiest to just try it and see.


For 2, it all depends on what you're booting from. E.g. the RK11 has a

simple

enough bootstrap that you can just enter it manually (although it gets old
after a while - I remember re-'programming' (think 'soldering iron' :-) a
castoff BM-792 someone gave us for our -11/40 so I wouldn't have to).

But if you're loading it over the console serial line, e.g. with PDP11GUI,

you

don't need any ROM bootstrap - the built in console ODT will be enough.
You can also load a bootstrap that way; I was booting off the QSIC RK11

with a

boostrap loaded over the console serial line; that was faster than the
bootstrap in the BDV11. This requires finding - or writing - a bootstrap,

which

for later DEC mass storage controllers is not trivial.

YMMV.


TLDR version - probably not!

Noel

KK11-A cache for -11/34A on eBait

[Noel Chiappa via cctalk]

Anyone want a KK11-A:

  https://www.ebay.com/itm/275173894774

US$200 sounds like a lot, I know, but KK11-A'S and FP11-A's are going for that
much; an FP11-A just went for US$250. And KK11-A's are rare; this is he first
one in a while.

Noel

Re: Is The M9312 Boot Module Essential?

[Noel Chiappa via cctalk]

> From: Rob Jarratt

> I suspect some of the other cards that were in the machine might do the
> necessary termination stuff.

Different answers for each part of the functionality.

1A and 1C fundamentally have be at the end of the bus, physically. So,
unlikely; since _other_ cards aren't, generally, designed to go there.

1B could be anywhere, but I've basically never seen anything but a CPU or a
terminator with 1B functionality - probably in part because the same physical
components uually do both 1A and 1B. (Oddball exception: M981 UNIBUS jumper,
in the -11/40 - but that's 'sort of' part of the CPU.)

2, yes. E.g. the KT24 UNIBUS map has sockets to hold bootstrap PROMs.
(Compatible with the M9312's.) Others, too; e.g. the KTJ11-B UNIBUS adapter
(although that is not seen in an -11/24). Maybe others, but I can't recall
off the top of my head.

Noel

RE: Is The M9312 Boot Module Essential?

[Rob Jarratt via cctalk]

I saw this reply later than the previous one. It confirms that I don't
*need* it for booting, but it would be useful.

I suspect some of the other cards that were in the machine might do the
necessary termination stuff.

Thanks

Rob

> -Original Message-
> From: cctalk  On Behalf Of Noel Chiappa via
> cctalk
> Sent: 19 February 2022 09:18
> To: cctalk@classiccmp.org
> Cc: j...@mercury.lcs.mit.edu
> Subject: Re: Is The M9312 Boot Module Essential?
> 
> > From: Rob Jarratt
> 
> > is the M9312 essential to ever get this machine to boot up an
operating
> > system?
> 
> Interesting question. I don't have my -11/24 running yet, so this reply is
> theoretical, not tried in practice (and as we all know, the difference
between
> theory and practice is even larger in practice than it is in theory), but
here
> goes.
> 
> The M9312 basically provides two things: 1) UNIBUS termination, and 2)
> boostrap ROM.
> 
> To further subdivide the former, it provides 1A) analog termination (i.e.
a
> resistance at the end of a transmission line that prevents reflections of
> signals passing down the otherwise un-terminated transmission lines of the
> bus), 1B) pullups (so those transmission lines normally float at roughly
3V,
> unless actively driven by one of the boards plugged into the bus) and 1C)
> 'SACK turnaround' (a start-up 'safety check' where an un-requested - and
> thus 'un-grabbed' by any device - bus grant from the CPU on start-up is
> 'turned around' by the terminator; this verifies that the grant lines are
un-
> broken between the CPU and the terminator - e.g. by someone forgetting to
> plug in a grant jumper).
> 
> 1A is not _absolutely_ necessary; this can be seen in small QBUS systems
> (the QBUS is, at the analog level, sort of identical to the UNIBUS; this
an be
> seen in the use of the same transceiver chips, such as 8641's, on both)
which
> can get away without 1A in small configurations. Whether it's needed on
your
> -11/24 is hard to predict, theoretically; the easiest thing is to just try
it and
> see. Note: it may 'work' without it, but not be as _reliable_ as with it.
> 
> 1B _is_ necessary, but can be provided anywhere on the bus; most
> UNIBUS/QBUS CPUs have it built in, and so does the KDF11-U of the -11/24:
> see pg.  of MP01028.
> 
> 1C is required by _some_ UNIBUS CPUs (ISTR that the -11/04 won't run
> without it), but the KDF11's in general don't; e.g. the -11/23 definitely
runs
> without it. The KDF11-U might have outboard circuitry to require it, but
I'm
> too lazy to grovel over the prints to see. Easiest to just try it and see.
> 
> 
> For 2, it all depends on what you're booting from. E.g. the RK11 has a
simple
> enough bootstrap that you can just enter it manually (although it gets old
> after a while - I remember re-'programming' (think 'soldering iron' :-) a
> castoff BM-792 someone gave us for our -11/40 so I wouldn't have to).
> 
> But if you're loading it over the console serial line, e.g. with PDP11GUI,
you
> don't need any ROM bootstrap - the built in console ODT will be enough.
> You can also load a bootstrap that way; I was booting off the QSIC RK11
with a
> boostrap loaded over the console serial line; that was faster than the
> bootstrap in the BDV11. This requires finding - or writing - a bootstrap,
which
> for later DEC mass storage controllers is not trivial.
> 
> YMMV.
> 
> 
> TLDR version - probably not!
> 
>   Noel

RE: Is The M9312 Boot Module Essential?

[Rob Jarratt via cctalk]

I am in the UK (Manchester). I suspect there are some people I know who would 
be able to lend me one.

 

The bit I am confused about is that I got a console prompt with just the CPU 
(M7133) and Unibus Map Module (M7134) installed. Presumably I could type in a 
bootstrap program from there?

 

Regards

 

Rob

 

From: Bill Degnan  
Sent: 19 February 2022 08:29
To: r...@jarratt.me.uk; Rob Jarratt ; General 
Discussion: On-Topic and Off-Topic Posts 
Subject: Re: Is The M9312 Boot Module Essential?

 

You need some way to initialize the system to the peripheral that contains 
the.OS media.  The m9312 is a general purpose co ntroller for that purpose.  
There are roms that install on the 9312 for almost any drive hardware.  When 
you get a system that comes with an M9312, it will have the appropriate 
peripheral Rom and console ROM installed from the factory.  The M9312 also had 
a console ROM monitor to allow a person to attach a terminal to enter bootstrap 
commands. 

 

But yes the *function* provided by the m9312 is necessary.  

 

Alternatively you can key in the bootstrap that tells your system how to boot 
your OS and communicate with your boot device.  

 

The m9312 is less useful without at least a console ROM

 

Where are you located?  Maybe someone nearby has in you could borrow just to 
see what you need.

Bill.

 

On Sat, Feb 19, 2022, 2:12 AM Rob Jarratt via cctalk mailto:cctalk@classiccmp.org> > wrote:

I have a PDP-11/24. I have never got very far with it because of power
supply problems which I am hopeful will be resolved soon. Looking at the
technical manual, it describes an M9312 bootstrap/terminator module. The
machine did not come with one of these.



I am not sure how the machine could have been useful without it. It did work
briefly before the PSU failed and I remember getting a console prompt. So,
is the M9312 essential to ever get this machine to boot up an operating
system?



Thanks



Rob

Re: Is The M9312 Boot Module Essential?

[Noel Chiappa via cctalk]

> From: Rob Jarratt

> is the M9312 essential to ever get this machine to boot up an operating
> system?

Interesting question. I don't have my -11/24 running yet, so this reply is
theoretical, not tried in practice (and as we all know, the difference
between theory and practice is even larger in practice than it is in theory),
but here goes.

The M9312 basically provides two things: 1) UNIBUS termination, and 2)
boostrap ROM.

To further subdivide the former, it provides 1A) analog termination (i.e. a
resistance at the end of a transmission line that prevents reflections of
signals passing down the otherwise un-terminated transmission lines of the
bus), 1B) pullups (so those transmission lines normally float at roughly 3V,
unless actively driven by one of the boards plugged into the bus) and 1C)
'SACK turnaround' (a start-up 'safety check' where an un-requested - and thus
'un-grabbed' by any device - bus grant from the CPU on start-up is 'turned
around' by the terminator; this verifies that the grant lines are un-broken
between the CPU and the terminator - e.g. by someone forgetting to plug in a
grant jumper).

1A is not _absolutely_ necessary; this can be seen in small QBUS systems (the
QBUS is, at the analog level, sort of identical to the UNIBUS; this an be
seen in the use of the same transceiver chips, such as 8641's, on both) which
can get away without 1A in small configurations. Whether it's needed on your
-11/24 is hard to predict, theoretically; the easiest thing is to just try
it and see. Note: it may 'work' without it, but not be as _reliable_ as with
it.

1B _is_ necessary, but can be provided anywhere on the bus; most UNIBUS/QBUS
CPUs have it built in, and so does the KDF11-U of the -11/24: see pg.  of
MP01028.

1C is required by _some_ UNIBUS CPUs (ISTR that the -11/04 won't run without
it), but the KDF11's in general don't; e.g. the -11/23 definitely runs
without it. The KDF11-U might have outboard circuitry to require it, but I'm
too lazy to grovel over the prints to see. Easiest to just try it and see.


For 2, it all depends on what you're booting from. E.g. the RK11 has a simple
enough bootstrap that you can just enter it manually (although it gets old
after a while - I remember re-'programming' (think 'soldering iron' :-) a
castoff BM-792 someone gave us for our -11/40 so I wouldn't have to).

But if you're loading it over the console serial line, e.g. with PDP11GUI,
you don't need any ROM bootstrap - the built in console ODT will be enough.
You can also load a bootstrap that way; I was booting off the QSIC RK11 with
a boostrap loaded over the console serial line; that was faster than the
bootstrap in the BDV11. This requires finding - or writing - a bootstrap,
which for later DEC mass storage controllers is not trivial.

YMMV.


TLDR version - probably not!

Noel

Re: Is The M9312 Boot Module Essential?

[Bill Degnan via cctalk]

You need some way to initialize the system to the peripheral that contains
the.OS media.  The m9312 is a general purpose co ntroller for that
purpose.  There are roms that install on the 9312 for almost any drive
hardware.  When you get a system that comes with an M9312, it will have the
appropriate peripheral Rom and console ROM installed from the factory.  The
M9312 also had a console ROM monitor to allow a person to attach a terminal
to enter bootstrap commands.

But yes the *function* provided by the m9312 is necessary.

Alternatively you can key in the bootstrap that tells your system how to
boot your OS and communicate with your boot device.

The m9312 is less useful without at least a console ROM

Where are you located?  Maybe someone nearby has in you could borrow just
to see what you need.
Bill.

On Sat, Feb 19, 2022, 2:12 AM Rob Jarratt via cctalk 
wrote:

> I have a PDP-11/24. I have never got very far with it because of power
> supply problems which I am hopeful will be resolved soon. Looking at the
> technical manual, it describes an M9312 bootstrap/terminator module. The
> machine did not come with one of these.
>
>
>
> I am not sure how the machine could have been useful without it. It did
> work
> briefly before the PSU failed and I remember getting a console prompt. So,
> is the M9312 essential to ever get this machine to boot up an operating
> system?
>
>
>
> Thanks
>
>
>
> Rob
>
>