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Re: Commodore history - The Commodore 128 by The 8-Bit Guy [message #374351 is a reply to message #374340] |
Sat, 06 October 2018 17:03 |
Andreas Kohlbach
Messages: 1456 Registered: December 2011
Karma: 0
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On Sat, 06 Oct 2018 19:32:53 +1000, Lucifer wrote:
>
> On Mon, 24 Sep 2018 17:05:05 -0400, Andreas Kohlbach
> <ank@spamfence.net> wrote:
>
>> Am following the Youtube channel of the 8-Bit-Guy who already did four
>> previous episodes of the Commodore history, starting with the PET.
>>
>> This one https://www.youtube.com/watch?v=wzMsgnnDIRE is about the C128
>> and with 30 minutes quite long but very entertaining and interesting in
>> my opinion. Especially because Bil Herd is interviewed. and gives insight
>> why it was built and what obstacles they had.
>
> They both think it has a C80 CPU and can use dool monitors.
> No way that guy could design a computer.
Z80? It indeed has. And has a built-in monitor.
Why would he want to design computer? He just reviews vintage computers
on his channel. And does this pretty well.
--
Andreas
My random thoughts and comments
https://news-commentaries.blogspot.com/
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Re: Commodore history - The Commodore 128 by The 8-Bit Guy [message #374778 is a reply to message #374351] |
Wed, 17 October 2018 17:05 |
Etienne von Wettingfe[1]
Messages: 180 Registered: December 2004
Karma: 0
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On 2018-10-06, Andreas Kohlbach <ank@spamfence.net> wrote:
> On Sat, 06 Oct 2018 19:32:53 +1000, Lucifer wrote:
>>
>> On Mon, 24 Sep 2018 17:05:05 -0400, Andreas Kohlbach
>> <ank@spamfence.net> wrote:
>>
>>> Am following the Youtube channel of the 8-Bit-Guy who already did four
>>> previous episodes of the Commodore history, starting with the PET.
>>>
>>> This one https://www.youtube.com/watch?v=wzMsgnnDIRE is about the C128
>>> and with 30 minutes quite long but very entertaining and interesting in
>>> my opinion. Especially because Bil Herd is interviewed. and gives insight
>>> why it was built and what obstacles they had.
>>
>> They both think it has a C80 CPU and can use dool monitors.
>> No way that guy could design a computer.
>
> Z80? It indeed has. And has a built-in monitor.
The C128 indeed has a Z80, for CP/M mode. In fact, the computer boots using
the Z80.
It has an Assembler monitor, but I think Lucifer means two screens at once.
It actually can, one using the 40 collumn mode and one the 80 character one.
I've even seen this done in real life.
--
Etienne Wettingfeld
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Re: Commodore history - The Commodore 128 by The 8-Bit Guy [message #374821 is a reply to message #374778] |
Thu, 18 October 2018 15:34 |
Andreas Kohlbach
Messages: 1456 Registered: December 2011
Karma: 0
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Senior Member |
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On 17 Oct 2018 21:05:34 GMT, Etienne von Wettingfeld wrote:
>
> On 2018-10-06, Andreas Kohlbach <ank@spamfence.net> wrote:
>> On Sat, 06 Oct 2018 19:32:53 +1000, Lucifer wrote:
>>>
>>> They both think it has a C80 CPU and can use dool monitors.
>>> No way that guy could design a computer.
>>
>> Z80? It indeed has. And has a built-in monitor.
>
> The C128 indeed has a Z80, for CP/M mode. In fact, the computer boots using
> the Z80.
Are you sure?
> It has an Assembler monitor, but I think Lucifer means two screens at once.
>
> It actually can, one using the 40 collumn mode and one the 80 character one.
But not at the same time AFAIK. When you switch the mode the content what
was displayed in the mode before just froze on the other display.
--
Andreas
My random thoughts and comments
https://news-commentaries.blogspot.com/
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Re: Commodore history - The Commodore 128 by The 8-Bit Guy [message #374847 is a reply to message #374821] |
Fri, 19 October 2018 04:51 |
Martijn van Buul
Messages: 326 Registered: December 2011
Karma: 0
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Senior Member |
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* Andreas Kohlbach:
> On 17 Oct 2018 21:05:34 GMT, Etienne von Wettingfeld wrote:
>> The C128 indeed has a Z80, for CP/M mode. In fact, the computer boots using
>> the Z80.
>
> Are you sure?
I'm quite sure Etienne is - and so am I ;)
>> It has an Assembler monitor, but I think Lucifer means two screens at once.
>>
>> It actually can, one using the 40 collumn mode and one the 80 character one.
>
> But not at the same time AFAIK. When you switch the mode the content what
> was displayed in the mode before just froze on the other display.
Well, that depends on your point of view. There are a few gotchas:
The 40 column screen used a video chip closely related to the one in the
C64. As such, it could only operate on 1MHz - if you wanted to use the
128's higher clockspeed (a blazing fast 2MHz), you were forced to blank
the 40 colum screen and use the 80 column screen instead (as it used a
separate video chip which didn't have this limitation).
So it did make sense to disable the 40 column screen, if the user switched
over to 80. This is assuming that the user didn't really have 2 monitors
to begin with, but only switched input source on their monitor - the 40
column output would go to waste anyway.
But that doesn't mean it couldn't be done to have both outputs active. In
fact, it was quite normal for software development.
A random demo I found on the interwebs:
https://www.youtube.com/watch?v=s2dcqkM-jeM
--
Martijn van Buul - pino@dohd.org
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Re: Commodore history - The Commodore 128 by The 8-Bit Guy [message #374860 is a reply to message #374847] |
Fri, 19 October 2018 16:24 |
Andreas Kohlbach
Messages: 1456 Registered: December 2011
Karma: 0
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Senior Member |
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On Fri, 19 Oct 2018 08:51:09 -0000 (UTC), Martijn van Buul wrote:
>
> * Andreas Kohlbach:
>> On 17 Oct 2018 21:05:34 GMT, Etienne von Wettingfeld wrote:
>
>>> It has an Assembler monitor, but I think Lucifer means two screens at once.
>>>
>>> It actually can, one using the 40 collumn mode and one the 80 character one.
>>
>> But not at the same time AFAIK. When you switch the mode the content what
>> was displayed in the mode before just froze on the other display.
>
> Well, that depends on your point of view. There are a few gotchas:
>
> The 40 column screen used a video chip closely related to the one in the
> C64. As such, it could only operate on 1MHz - if you wanted to use the
> 128's higher clockspeed (a blazing fast 2MHz), you were forced to blank
> the 40 colum screen and use the 80 column screen instead (as it used a
> separate video chip which didn't have this limitation).
>
> So it did make sense to disable the 40 column screen, if the user switched
> over to 80. This is assuming that the user didn't really have 2 monitors
> to begin with, but only switched input source on their monitor - the 40
> column output would go to waste anyway.
>
> But that doesn't mean it couldn't be done to have both outputs active. In
> fact, it was quite normal for software development.
>
> A random demo I found on the interwebs:
>
> https://www.youtube.com/watch?v=s2dcqkM-jeM
Thanks for the information.
I was watching a video on Youtube a while ago where the presenter showed
how the 40 column froze when switching to 80 columns. I just took 20
minutes to find it but was unsuccessful.
--
Andreas
My random thoughts and comments
https://news-commentaries.blogspot.com/
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Re: Commodore history - The Commodore 128 by The 8-Bit Guy [message #374897 is a reply to message #374847] |
Mon, 22 October 2018 01:10 |
Etienne von Wettingfe[1]
Messages: 180 Registered: December 2004
Karma: 0
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Senior Member |
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On 2018-10-19, Martijn van Buul <pino@dohd.org> wrote:
> * Andreas Kohlbach:
>> On 17 Oct 2018 21:05:34 GMT, Etienne von Wettingfeld wrote:
>
>>> The C128 indeed has a Z80, for CP/M mode. In fact, the computer boots using
>>> the Z80.
>>
>> Are you sure?
>
> I'm quite sure Etienne is - and so am I ;)
IIRC it has to do with the ability to auto-boot CP/M.
It checks if there's a CP/M disk, if yes it boots it, if no it switches
to the 8502.
--
Etienne Wettingfeld
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Re: Commodore history - The Commodore 128 by The 8-Bit Guy [message #374915 is a reply to message #374897] |
Tue, 23 October 2018 05:40 |
Martijn van Buul
Messages: 326 Registered: December 2011
Karma: 0
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Senior Member |
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* Etienne von Wettingfeld:
> IIRC it has to do with the ability to auto-boot CP/M.
Well... Close :)
The C128 was designed to be compatible with all official C64 addons -
which included the C64 CP/M cartridge, which had compatibility issues
on later revision C64s already. Designing in the Z80 (so the CP/M cartridge
would be redundant, and no longer an issue..) was cheaper than trying to work
around the issues.
There were other problematic cartridges: Cartridges that (ab)used Ultimax
mode to hijack the reset-, NMI- and interrupt vectors. This included some
of Commodore's own (including the Magic Voice). These would cause problems,
since the system hadn't been configured for C64 mode yet.
This is the real reason the c128 initially boots using the Z80: It probes
whether the system needs to boot in CP/M, 128 or 64 mode, while the 8502
was still halted.
Get it from the horse's mouth (Not that I'd call Bil a horse, mind):
https://www.reddit.com/r/c128/comments/682da4/c128_ama_from_ bil_herd/
--
Martijn van Buul - pino@dohd.org
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Re: Commodore history - The Commodore 128 by The 8-Bit Guy [message #374916 is a reply to message #374821] |
Tue, 23 October 2018 06:20 |
wwww.leser
Messages: 21 Registered: March 2013
Karma: 0
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Junior Member |
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On Thursday, October 18, 2018 at 9:34:22 PM UTC+2, Andreas Kohlbach wrote:
> On 17 Oct 2018 21:05:34 GMT, Etienne von Wettingfeld wrote:
>>
>> On 2018-10-06, Andreas Kohlbach <ank@[...]> wrote:
>>> On Sat, 06 Oct 2018 19:32:53 +1000, Lucifer wrote:
>>>>
>>>> They both think it has a C80 CPU and can use dool monitors.
>>>> No way that guy could design a computer.
>>>
>>> Z80? It indeed has. And has a built-in monitor.
>>
>> The C128 indeed has a Z80, for CP/M mode. In fact, the computer boots using
>> the Z80.
>
> Are you sure?
>
>> It has an Assembler monitor, but I think Lucifer means two screens at once.
>>
>> It actually can, one using the 40 collumn mode and one the 80 character one.
>
> But not at the same time AFAIK. When you switch the mode the content what
> was displayed in the mode before just froze on the other display.
> --
> Andreas
>
> My random thoughts and comments
> https://news-commentaries.blogspot.com/
Not making use of any dirty hacks or programming tricks at all, you can easily convince yourself that neither of the two screens freezes: With both displays connected and active, call SPRDEF from 80 column mode to put some pixels in sprite number 1. Leave the editor (SHIFT+RETURN, RETURN), then make your sprite visible, e.g. by entering "SPRITE 1,1,2,0,0,0,0". Now try "MOVSPR 1,115#7" and enjoy two displays at once, both non-frozen.
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