Curious Mark has Model 77 woes

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Grant Taylor

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Aug 14, 2021, 9:15:10 PMAug 14
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Curious Mark (YouTube), Kern Sherif, and soon Tube Time are debugging a
model 77 that died on them.

There are currently two videos with hints at a third. I suspect this
video series will end up being interesting. They will likely go to
great lengths to get the model 77 working.

They may punt and replace it with another MCA system as their stated
goal is to get the S/370 + Bus & Tag interface working so that they can
communicate with some B&T tape drives and printer.



--
Grant. . . .
unix || die

Tomas Slavotinek

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Aug 15, 2021, 12:30:18 PMAug 15
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Yep, can't wait to see where this series goes. Here are the first two
episodes for those who are not subscribed (you should be!):

https://youtu.be/GjCUsmro2VY
https://youtu.be/CMyKVerpyaI

Marc has some unorthodox delidding methods... :-D

Grant Taylor

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Aug 15, 2021, 12:43:38 PMAug 15
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On 8/14/21 7:15 PM, Grant Taylor wrote:
> Kern Sherif

*Ken Shirriff

Sorry for the typo - nay butchering - Ken, no disrespect intended.

Grant Taylor

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Aug 15, 2021, 12:45:45 PMAug 15
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On 8/15/21 10:30 AM, Tomas Slavotinek wrote:
> Yep, can't wait to see where this series goes. Here are the first
> two episodes for those who are not subscribed (you should be!):

Agreed. I have always enjoyed watching Mark's and Ken's efforts.

> https://youtu.be/GjCUsmro2VY
> https://youtu.be/CMyKVerpyaI

Thank you for the links. It was problematic for me to get them into my
news client when I originally posted. (Local client had the videos,
where I was RDPed to something to run VNC to my news client. Copy and
what you say???)

> Marc has some unorthodox delidding methods... :-D

~chuckle~

I think my favorite was the end mill and a blow torch.

Tomas Slavotinek

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Aug 15, 2021, 1:00:27 PMAug 15
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And for the sake of completeness, here is Ken's blog:

http://www.righto.com/

A lot of IBM goodness, among other things. Borderline p0rnographic...

Tomas Slavotinek

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Aug 15, 2021, 1:05:21 PMAug 15
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He has a lot of toys and is not afraid to use them!

(btw Dave and I are in touch with Marc and his team regarding the Model
77 problem)


Grant Taylor

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Aug 15, 2021, 6:15:02 PMAug 15
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On 8/15/21 11:05 AM, Tomas Slavotinek wrote:
> He has a lot of toys and is not afraid to use them!

Indeed.

> (btw Dave and I are in touch with Marc and his team regarding the
> Model 77 problem)

Cool.

I tweeted Mark a few times while watching the video. The fact that the
convenience (reference) partition is not required ~> reference disks
will work with or without the convenience partition. The fact that it's
possible to ""bless (for lack of a better word) the reference disk after
Windows (et al.) messes up it's marker.

I got the distinct impression that PS/2s were ... foreign to Mark. So,
being in contact with someone that's more familiar is a good thing. :-)

Louis Ohland

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Aug 15, 2021, 9:31:01 PMAug 15
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I surfed both videos. I'm not sure what is going on.

Bermuda, VERY clean looking. If they would drop to this frequency, I'd
be interested. 370 and tape to tape drives. Gung-ho!

Tomas Slavotinek

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Aug 16, 2021, 12:28:38 PMAug 16
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Part 3 is up:

https://youtu.be/Nyqo-XOuHK4

On 15.8.2021 3:15, Grant Taylor wrote:

Grant Taylor

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Aug 16, 2021, 7:52:29 PMAug 16
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On 8/16/21 10:28 AM, Tomas Slavotinek wrote:
> Part 3 is up:

I'm somewhat disappointed by that outcome.

Though I can't say as I'm surprised.

I wonder what they will do / use as an MCA system to interface with the
Bus & Tag equipment.

Louis Ohland

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Aug 16, 2021, 8:27:44 PMAug 16
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Well, they tried bread boarding.

Why don't they findt a spare Bermuda on flea-buy?

Lacuna would need the correct riser.

The Bermuda IMHO is more stable compared to the Lacuna. 32MB on the
system board is pretty good.

Louis Ohland

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Aug 16, 2021, 8:29:43 PMAug 16
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Spare Bermuda system board.

Try not to burn this one.

Grant Taylor

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Aug 17, 2021, 12:08:23 AMAug 17
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On 8/16/21 6:27 PM, Louis Ohland wrote:
> Well, they tried bread boarding.

Eh ... they bread boarded to read the output from the parallel port.
Mark usually does many things quite a bit more complex on bread board.

> Why don't they findt a spare Bermuda on flea-buy?

There was a scene about that. They showed one for > $250 and made a
comment about not wanting to pay that much.

Louis Ohland

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Aug 17, 2021, 11:36:11 AMAug 17
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Bermuda system board. Yup, buying a 9577 would be spendy.

schimmi

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Aug 17, 2021, 1:14:09 PMAug 17
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Tomas Slavotinek

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Aug 17, 2021, 2:39:14 PMAug 17
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Yeah, they are covered, thanks to Dave :).

Hopefully they will have more luck with the replacement board...

IBMMuseum

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Aug 17, 2021, 10:31:22 PMAug 17
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> >>> There was a scene about that. They showed one for > $250
> >>> and made a comment about not wanting to pay that much.
> >
> > Nice one, IBM Museum :D
> > https://www.youtube.com/watch?v=P3-krxA3LZ0
> >
> Yeah, they are covered, thanks to Dave :).
>
> Hopefully they will have more luck with the replacement board...

And it has a Trinity "PowerStacker" CPU (based on the AMD 5x86-133) - It sure is fast!

I've gained 120 new subscribers - a third of what I had before - in two days. The planar will arrive on Friday by the USPS, but I think it will be sooner.

Tomas Slavotinek

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Aug 18, 2021, 6:45:54 AMAug 18
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Looks like Marc isn't giving up just yet. He asked for some more details
about the planar and the used ASICs/GAs...

IBMMuseum

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Aug 18, 2021, 9:39:03 AMAug 18
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On Wednesday, August 18, 2021 at 4:45:54 AM UTC-6, Tomas Slavotinek wrote:
> Looks like Marc isn't giving up just yet. He asked for some more details
> about the planar and the used ASICs/GAs...

Yeah, he's not going to give up and seems to be genuinely curious - I think he was pleasantly surprised that his "undocumented" comment got proven false. It is going to be a great interaction.

Louis Ohland

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Aug 18, 2021, 9:39:47 AMAug 18
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Did he ask you?

If he really wandts to go big... Look at a PS/2 PSU from a 90 or 95 and
give us schematics or something useful for repairs.

Tomas Slavotinek

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Aug 18, 2021, 10:52:41 AMAug 18
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On 18.8.2021 15:39, Louis Ohland wrote:
> Did he ask you?

Yeah after the 2nd episode we have talked about the board failure with
Eric (TubeTime) for a bit, and Marc himself emailed me again earlier today.

> If he really wandts to go big... Look at a PS/2 PSU from a 90 or 95 and
> give us schematics or something useful for repairs.

Eh, he already "went big" with projects like the AGC or Xerox Alto... I
don't think he cares much about some "PC" power supply. PSUs are one of
the most boring components tbh... (only the failure modes are
spectacular sometimes)

Grant Taylor

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Aug 21, 2021, 12:42:19 AMAug 21
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On 8/17/21 11:14 AM, schimmi wrote:
> Nice one, IBM Museum :D
> https://www.youtube.com/watch?v=P3-krxA3LZ0

Why did he refer to the convenience partition as "IML"?

Wouldn't the system fail to boot if it couldn't find the initial
microcode to load?

I've run the systems without the convenience partitions or hard drives.
So ... why IML?

Tomas Slavotinek

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Aug 21, 2021, 3:42:19 AMAug 21
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On 21.8.2021 6:42, Grant Taylor wrote:
> On 8/17/21 11:14 AM, schimmi wrote:
>> Nice one, IBM Museum :D
>> https://www.youtube.com/watch?v=P3-krxA3LZ0
>
> Why did he refer to the convenience partition as "IML"?

Because that's what it really is in case of the Bermuda-based Models
76/77 - an IML partition.

> Wouldn't the system fail to boot if it couldn't find the initial
> microcode to load?

Yes, there's no fallback Stage 2 code in the Bermuda ROM, so if it can't
find a compatible IML image anywhere (floppy, IBM SCSI) it will print an
error and then halt.
> I've run the systems without the convenience partitions or hard drives.
> So ... why IML?

If there's no IML partition you have to feed it the reference disk and
it will load the IML image from there. Once that's done, you can load
your OS from another floppy (the IML image will stay in RAM until you
power down the system or force cold boot in some other way).


IBMMuseum

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Aug 23, 2021, 12:24:48 AMAug 23
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> Why did he refer to the convenience partition as "IML"?

And he is a "big iron" - not necessarily IBM - guy. He's also now aware that I have four System/34s. It's going to be a productive association all around.

Tomas Slavotinek

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Oct 18, 2021, 3:14:08 PMOct 18
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Part 4 is finally up:

https://youtu.be/wsLpe4lLhbo

Interesting fault...

On 15.8.2021 3:15, Grant Taylor wrote:

IBMMuseum

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Oct 18, 2021, 4:40:03 PMOct 18
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On Monday, October 18, 2021 at 1:14:08 PM UTC-6, Tomas Slavotinek wrote:
> Part 4 is finally up:
>
> https://youtu.be/wsLpe4lLhbo
>
> Interesting fault...

Yep - I started to see my subscription count suddenly increase yesterday at this time. At the start of my live-stream on Saturday, I was at 599 subscribers - within 48 hours, it was at 699. What will another 24 hours hold?

Tomas Slavotinek

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Nov 15, 2021, 1:42:41 PM (11 days ago) Nov 15
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Part 5 of the M77 series is up:
https://youtu.be/Y6UprDq8LAQ

And the planar is finally repaired for good... :)

schimmi

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Nov 15, 2021, 4:30:22 PM (11 days ago) Nov 15
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03:30

pure marketing machines. and you wanted to remove 'captialism' :P

glad, they could save it.

IBMMuseum

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Nov 15, 2021, 5:24:26 PM (11 days ago) Nov 15
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> > Part 5 of the M77 series is up:
> > https://youtu.be/Y6UprDq8LAQ
> >
> > And the planar is finally repaired for good... :)

A via - maybe something to look at with the Bermuda RTC issue...

> > > They may punt and replace it with another MCA system as their
> > > stated goal is to get the S/370 + Bus & Tag interface working so
> > > that they can communicate with some B&T tape drives and printer.

I spot a microchannel "long" 3270 emulation adapter at 0:15 too - It would be nice to map out what they have planned.

Grant Taylor

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Nov 15, 2021, 5:30:46 PM (11 days ago) Nov 15
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On 11/15/21 3:24 PM, IBMMuseum wrote:
> I spot a microchannel "long" 3270 emulation adapter at 0:15 too -
> It would be nice to map out what they have planned.

I thought that Mark had said that they were wanting to connect a bus &
tag tape drive to the system so that they could read old tapes.

I would not be surprised if they were going to have (some version of)
MVS run on the P/370 card copy from physical tape to a virtual tape, or
maybe even virtual card punch, so that they can ultimately use the
(virtual) copy of what was on the tape elsewhere.

This feels like a scaffolding project. Something that's being done in
support of something else.

Louis Ohland

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Nov 15, 2021, 5:37:17 PM (11 days ago) Nov 15
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I still have that full length card with the big chip.

IBMMuseum

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Nov 15, 2021, 6:09:44 PM (11 days ago) Nov 15
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> I still have that full length card with the big chip.

I've got a few myself, getting pictures to Major Tom soon...
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