"Bob Armstrong" <bob at jfcl.com> skrev:
> Is there a way to boot XXDP+ from a secondary MSCP controller (e.g. CSR at
> 760334) ?
>
>
>
> This isn't a PDP-11 boot ROM issue - the -11 (a 11/53+ in this instance)
> ROM has no problem booting from a secondary controller.
>
>
>
> The issue is that, once started, XXDP doesn't know that it should talk to
> this alternate CSR address and promptly dies.
I don't think so. As far as I know, XXDP don't take any hints from the boot rom
code. You need to build a specific XXDP distribution with a monitor using a
device driver talking to the controller at that alternate address.
Not sure how you would do that. I've never tried getting system device drivers
in XXDP to talk to devices at other than standard addresses.
Johnny
--
Johnny Billquist || "I'm on a bus
|| on a psychedelic trip
email: bqt at softjar.se || Reading murder books
pdp is alive! || tryin' to stay hip" - B. Idol
> Glen Slick (glen.slick at gmail.com) wrote:
>On simh it appears that attaching the disk to rqb0
>resulted in a unit 0 drive on the secondary MSCP controller and I
>couldn't find any options to configure the unit number.
Does XXDP require all MSCP unit numbers be unique? I thought that was
just RSTS...
You can do this in simh by attaching the xxdp25.rd52 image to the device
rqb2, since the primary rq controller just uses drives 0/1. When I did
this, I got the same result (i.e. a halt) as before.
>Have you tried this on the real hardware yet? On the real hardware
>what unit is the drive you are trying to boot on the SQ703?
Yes, on the real hardware it doesn't halt; it just seems to hang forever.
The dialog goes something like this (I'm retyping this from my VT320, so
excuse any typos) -
Commands are Help, Boot, List, Map, Test and Wrap.
Type a command then press the RETURN key: B/A DU2
Address = 17760334
DU2
... hangs here ....
BTW, I was wrong before; my SCSI controller is actually a SQ739 rather
than a 703, but I doubt that changes anything.
There are two SCSI devices on the SQ739, an Exabyte 8505 tape drive and a
RRD43 (a Toshiba something or other) CDROM. The SQ739 is configured for
17760334 for MSCP and the RRD43 is configured as MSCP unit 2 (i.e. DU2).
Maybe there's something wrong with the way I'm making the CD image? Did
you do anything special when you made yours?
Thanks,
Bob
> From: ard at p850ug1.demon.co.uk
---snip--->> > Alternatively make a stroboscope disk (either copy the one off a TM100 > pulley, or work out howm many segments you need and write a trivial bit > of postscript to draw it), stick that on the spindle pulley or > direct-drive motor rotor and view it under amins-powered lamp. >
Hi
For 60 Hz it is easy.
If one uses a light like a neon, it will flash 120 times.
An LED is just one direction unless one uses a full wave
bridge to get a forward pulse on each cycle.
As a single phase it is only 60 Hz. One thing to remember
is that the LED can't take too high of a back voltage.
Most red ones are rated for about 10V someplace.
If feeding it with an AC source greater than the
LEDs rate back voltage, one should do something
to protect it. A series rectifier diode will work and
reduce the power in the dropping resistor.
A shunt diode will also work but the resistor will
conduct on both half cycles.
Lets assume we have 120 flashes per second as from a neon since
the same disk would work with the 60 flash LED.
A disk spinning at 300 RPM does 5 rotations per second.
if we divide 120 by 5, we get 24 flashes per rotation.
We just need to create a disk with 24 dark and 24 white
segments.
For a 360, we get 6 rotations a second. That works
out to 20 flashes per rotation. That is 20 black and
20 white spaces. This could be printed with a spread sheet
and a pie chart print, as I stated before.
For 50 Hz, the 300 RPM is easy but the 360 doesn't work
out. One gets 16.66 flashes per rotation.
The only way I can think to make this work is to make a spiral
that would have 50 dark and light strips over 3 revolutions.
Ones eye would tend to follow the spiral. I'm not sure how
to do this with a spread sheet.
Maybe it could be done with some postscript code but
I'm not sure how.
Dwight
_________________________________________________________________
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Just found out about this (see below). I apologise if someone has already sent an email to the list about it (still behind in my emails).
Regards,
Andrew B
aliensrcooluk at yahoo.co.uk
> Amazing that 27 years after its launch there is > planned the 12th annual meet of the ZX Team
> in Mahlerts Germany.
>
>
> 11th -13th April 2008
>
> www.zx81.de
>
------------Original Messages:
> Date: Thu, 22 Nov 2007 12:17:31 -0800 (PST)
> From: Fred Cisin
> Subject: Re: FD400 drive troubleshooting
>
>>Many/most drives have 50Hz/60Hz zebra discs on the flywheel, for using a
>>flickering fluorescent light.
>
> Which just happens to be the ratio of 300RPM vs 360RPM, so that on a 300RPM
> strobe disk w/a 60Hz light the 60Hz bars = 300RPM and the 50Hz bars = 360RPM.
>
> FWIW,
Hi
I think you have the ratio backward. The 60 Hz disk for 360 RPM
can be used for the 50 Hz 300 RPM.
Dwight
----------Reply:
Well, unless you're just saying that a 60Hz 360RPM strobe disk (if you had one)
would also sync at 300RPM under a 50Hz light, I don't see what's backward.
The point was that 50/60Hz 300RPM strobe disks are common, and if you're in
a 60Hz zone you can use the same disk for 8" and dual-speed drives as well.
m
Hi Alan,
You made a posting 5 years ago looking for cct for Comark 1905 Insulation
Meter.
Did you get any joy? - I also am looking, and as with you, current Comark
gave me the brush-off.
Best regards,
Peter.
--------------Original Message:
Date: Sat, 24 Nov 2007 00:14:35 +0000 (GMT)
From: ard at p850ug1.demon.co.uk (Tony Duell)
Subject: Re: FD400 drive troubleshooting
> >>Many/most drives have 50Hz/60Hz zebra discs on the flywheel, for using a
> >>flickering fluorescent light.
> >
> > Which just happens to be the ratio of 300RPM vs 360RPM, so that on a 300RPM
> > strobe disk w/a 60Hz light the 60Hz bars = 300RPM and the 50Hz bars = 360RPM.
> >
> > FWIW,
>
> Hi
> I think you have the ratio backward. The 60 Hz disk for 360 RPM
> can be used for the 50 Hz 300 RPM.
I think you're both saying the same thing. Assuming you're in the States
and have a 60Hz light source available, then take the standard '300 rpm
50/60Hz' strobe disk found on, say, the TM100. The '60Hz bars' will let
you check a 300rpm spindle (obviosuly), the '50Hz bars' _used with a
60-Hz lamp_ will check a 360rpm spindle.
-tony
-------------Reply:
Yes, I think that's exactly what I said, although I included Canada and any
other place that uses 60Hz, and I don't see what's backward about it.
I only mentioned this happy coincidence (and almost regret having done so)
because I thought perhaps not everyone in 60Hz country was aware that
they could use a common 50/60Hz strobe disk off a 300RPM drive to also
check the speed of a 360RPM 8" or dual-speed drive.
m
> Glen Slick (glen.slick at gmail.com) wrote:
>What are you using for the primary and secondary MSCP controllers and
>what disk units do you have configured on each controller?
What I'm trying to do is very much like you configuration - my real 11/53
has a KDA50 with 2xRF70 drives and the secondary MSCP controller is a SQ703.
You can demonstrate my problem with simh, though - build a bootable XXDP+
v2.5 on a RD52 image, and then do this...
sim> show cpu
CPU, 11/53, NOCIS, idle disabled, autoconfiguration on, 3072KB
sim> show rq
RQ, address=17772150-17772153*, no vector, 2 units
RQ0, 159MB, attached to one.rd54, write enabled, RD54
RQ1, 159MB, attached to two.rd54, write enabled, RD54
sim> show rqb
RQB, address=17760334-17760337*, no vector, 30MB, attached to
xxdp25.rd52, write enabled, RD52
sim> b rqb0
HALT instruction, PC: 016146 (CLR (R1))
If you attach xxdp25.rd52 to rq0, it'll boot fine -
sim> att rq0 xxdp25.rd52
sim> b rq0
BOOTING UP XXDP-XM EXTENDED MONITOR
... etc, etc ....
I suspect you have to patch something in the XXDP+ image with UPDAT to get
it to talk to the secondary CSR, but I don't know the details.
Thanks,
Bob
I found an item based on a Commodore press release in Byte Magazine,
February 1978, Page 190. This establishes the first shipment as mid October
1977.
Commodore Ships First PET Computers
(Photo of Chuck Peddle)
The PET computer made its debut recently as the first 100 units were shipped
to waiting customers in mid October 1977. Here Commodore Systems Division
Director Chuck Peddle is pictured with the PETs undergoing final checkout.
Shipments were made about six weeks later than expected, according to
Peddle. The delay was due in part to time consuming quality control measures
and the material flow problem in starting up the production lines. "In this
business," Peddle argued, "six weeks is actually pretty good." Many of the
first units were delivered to customers who intend to develop software for
the PET. Commodore plans to create a publishing house for programs developed
by users as well as employees. The company plans to increase production of
the PET computers to several thousand per month by early 1978. The basic PET
with 4 K memory is priced at $595, while the 8 K memory version is $795,
>from Commodore Business Machines Inc, 901 California Av, Palo Alto CA 94304,
(415) 326-4000.
You can find a scan of the item here:
http://www.swtpc.com/mholley/BYTE/Feb1978/Byte_Feb_1978_pg190.jpg
Michael Holley
Is there a way to boot XXDP+ from a secondary MSCP controller (e.g. CSR at
760334) ?
This isn't a PDP-11 boot ROM issue - the -11 (a 11/53+ in this instance)
ROM has no problem booting from a secondary controller.
The issue is that, once started, XXDP doesn't know that it should talk to
this alternate CSR address and promptly dies.
Thanks,
Bob Armstrong
