• Commodore history - The Commodore 128 by The 8-Bit Guy

    From Andreas Kohlbach@3:770/3 to All on Mon Sep 24 17:05:05 2018
    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.
    --
    Andreas

    My random thoughts and comments
    https://news-commentaries.blogspot.com/
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  • From Harry Potter@3:770/3 to All on Wed Oct 3 07:25:18 2018
    I like that movie. :)
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  • From Lucifer@3:770/3 to ank@spamfence.net on Sat Oct 6 19:32:53 2018
    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.
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  • From Etienne von Wettingfeld@3:770/3 to Andreas Kohlbach on Wed Oct 17 21:05:34 2018
    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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  • From Andreas Kohlbach@3:770/3 to Etienne von Wettingfeld on Thu Oct 18 15:34:20 2018
    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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  • From Martijn van Buul@3:770/3 to All on Fri Oct 19 08:51:09 2018
    * 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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  • From Andreas Kohlbach@3:770/3 to Martijn van Buul on Fri Oct 19 16:24:07 2018
    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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  • From Etienne von Wettingfeld@3:770/3 to Martijn van Buul on Mon Oct 22 05:10:24 2018
    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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  • From Andreas Kohlbach@3:770/3 to Etienne von Wettingfeld on Mon Oct 22 16:17:29 2018
    On 22 Oct 2018 05:10:24 GMT, Etienne von Wettingfeld wrote:

    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.

    Thank you.
    --
    Andreas

    My random thoughts and comments
    https://news-commentaries.blogspot.com/
    --- SoupGate-Win32 v1.05
    * Origin: Agency HUB, Dunedin - New Zealand | Fido<>Usenet Gateway (3:770/3)
  • From Martijn van Buul@3:770/3 to All on Tue Oct 23 09:40:57 2018
    * 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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  • From ArcadeAge@3:770/3 to Andreas Kohlbach on Tue Oct 23 03:20:00 2018
    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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