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Olivetti/Logabax/AT&T/Toshiba 640x400 hi-res graphics mode

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First post, by Jo22

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Hello everyone,

I'd like to ask you a favour..

Inspired by the unknown Compaq graphics hardware in this thread over here,
I did a few tests with the Olivetti 640x400x1 graphics mode.

It seems that Quick-Basic 4.5 does indeed support this mode.
Now I wonder how many PC systems were compatible to this CGA extension.

If you have some spare free time and don't know what to do with it,
please run that little QB program on your old CGA machine(s).

Perhaps we're lucky and some of them do support that mode inofficialy.
Or maybe not. Emulators, such as PC-Speed, ATonce, etc. are also welcome. 😀

Any feedback/comments welcome. You can also post some pictures, if you wish.
(Since this is a low-priority topic you may want to use external picture storage, too)

9Gll950.png

Video: http://youtu.be/k4B0Y7X3WHU

More information:
http://en.wikipedia.org/wiki/Olivetti_M24
http://en.wikipedia.org/wiki/Toshiba_T3100

http://www.youtube.com/watch?v=CsNngpf96Ro
http://www.computinghistory.org.uk/det/4587/Toshiba-T3100/
http://www.minuszerodegrees.net/manuals/Toshi … 20-%20Flyer.pdf

http://www.old-computers.com/museum/computer.asp?c=535
http://www.old-computers.com/museum/computer.asp?c=154
http://www.old-computers.com/museum/computer.asp?c=531

Attachments

  • Filename
    m24.zip
    File size
    29 KiB
    Downloads
    131 downloads
    File comment
    QB 4.5 "CIRCLE" sample program (slightly altered).
    Sets SCREEN 2 (CGA) and SCREEN 4 (Olivetti).
    File license
    Fair use/fair dealing exception

"Time, it seems, doesn't flow. For some it's fast, for some it's slow.
In what to one race is no time at all, another race can rise and fall..." - The Minstrel

//My video channel//

Reply 1 of 9, by Jo22

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Update. I'm currently experimenting with the 640x400 monochrome mode again.
I've found some information regarding the structure of the video memory and its size.

You're still invited to join testing - any suggestions and ideas welcome as always. 😀

Attachments

  • m24_640_400_gfm.gif
    Filename
    m24_640_400_gfm.gif
    File size
    25.48 KiB
    Views
    2061 views
    File comment
    Diagram 640x400 memoy layout
    File license
    Fair use/fair dealing exception

"Time, it seems, doesn't flow. For some it's fast, for some it's slow.
In what to one race is no time at all, another race can rise and fall..." - The Minstrel

//My video channel//

Reply 2 of 9, by Jo22

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Hi everyone, by the end of the last year, I started working on CGAView again.
Here's an experimental release that includes some improvements (hopefully) and support for the 640x400 mode.
It also supports crossloading so far, so you can, for example, display these hi-res pictures on normal CGAs, too.

Hope you enjoy! ^^

As usual, please feel free to share your opinions below.

Attachments

  • Filename
    cviewx.zip
    File size
    384.07 KiB
    Downloads
    135 downloads
    File comment
    CGAView X v0.3
    Experimental version.
    Adds M24/AT&T/Logabax 640x400 mode.
    File license
    Fair use/fair dealing exception

"Time, it seems, doesn't flow. For some it's fast, for some it's slow.
In what to one race is no time at all, another race can rise and fall..." - The Minstrel

//My video channel//

Reply 3 of 9, by ediflorianUS

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Hi , I am ready to help test your files. I have Toshiba T3100e , and unable to start win (L.E. managed to start win2.03... work-in progress) and it seems that all EGA/VGA game requirements are out of my reach so... only CGA/Olivetti/AT&T remains.... Downloaded files now, will boot up system and give it a go.

L.E.
I can report that most of the things work ok on t3100e
last image did not load but that is about all.... (and of coarse no vga mode set with the set program)

My 80486-S i66 Project

Reply 4 of 9, by Jo22

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ediflorianUS wrote on 2021-01-17, 09:41:
Hi , I am ready to help test your files. I have Toshiba T3100e , and unable to start win (L.E. managed to start win2.03... work- […]
Show full quote

Hi , I am ready to help test your files. I have Toshiba T3100e , and unable to start win (L.E. managed to start win2.03... work-in progress) and it seems that all EGA/VGA game requirements are out of my reach so... only CGA/Olivetti/AT&T remains.... Downloaded files now, will boot up system and give it a go.

L.E.
I can report that most of the things work ok on t3100e
last image did not load but that is about all.... (and of coarse no vga mode set with the set program)

Thank you very much for your help! 🙂👍

PS: Sorry for the late reply, just noticed your posting!

"Time, it seems, doesn't flow. For some it's fast, for some it's slow.
In what to one race is no time at all, another race can rise and fall..." - The Minstrel

//My video channel//

Reply 5 of 9, by Plasma

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FYI QB has a BIOS check before it allows SCREEN 4 to run. If you make this change to either QB.EXE/QBASIC.EXE or your compiled program, then 640x400 will work on "Super CGA" Compaq/Toshiba systems and DOSBox-X.

Reply 6 of 9, by Jo22

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Plasma wrote on 2022-07-03, 05:03:

FYI QB has a BIOS check before it allows SCREEN 4 to run. If you make this change to either QB.EXE/QBASIC.EXE or your compiled program, then 640x400 will work on "Super CGA" Compaq/Toshiba systems and DOSBox-X.

Thank you! ^^

Edit: Here they go.

Attachments

  • Filename
    m24_fix.zip
    File size
    28.41 KiB
    Downloads
    69 downloads
    File license
    Fair use/fair dealing exception
  • Filename
    cviewx_fix.zip
    File size
    38.33 KiB
    Downloads
    71 downloads
    File license
    Fair use/fair dealing exception

"Time, it seems, doesn't flow. For some it's fast, for some it's slow.
In what to one race is no time at all, another race can rise and fall..." - The Minstrel

//My video channel//

Reply 7 of 9, by Jo22

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Hi. There's a recent video about "Super CGA" graphics cards.
It also demonstrates the Olivetti 640x400 mode.

https://www.youtube.com/watch?v=xNsK_F4JlG4

Also interesting is this older one :

https://www.youtube.com/watch?v=mUCh46_MzZU

"Time, it seems, doesn't flow. For some it's fast, for some it's slow.
In what to one race is no time at all, another race can rise and fall..." - The Minstrel

//My video channel//

Reply 8 of 9, by Jo22

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Quick update. I've noticed that CGAView X doesn't run properly in PC-Ditto emulator.

Maybe it's because the utility clears the screen during start and then sets plain text-mode.
- Which in turn might not be supported in CGA machine mode, if it's MDA-specific (there's a separate machine mode for MDA).

The updated utility now does use CGA's high-resolution graphics mode instead. I know, it's just a temporary fix.
I would have also rather done it right, but I'm a bit busy right now (life and things). Hope you don't mind.

Edited.

Attachments

  • pc_ditto_corrupted.gif
    Filename
    pc_ditto_corrupted.gif
    File size
    4.37 KiB
    Views
    189 views
    File license
    Fair use/fair dealing exception
  • pc_ditto_ok.gif
    Filename
    pc_ditto_ok.gif
    File size
    2.94 KiB
    Views
    189 views
    File license
    Fair use/fair dealing exception
  • Filename
    cviewx_fix2.zip
    File size
    40.58 KiB
    Downloads
    7 downloads
    File comment
    CGAView X v0.5; uses hires graphics mode for text, patched for generic AT&T graphics hw
    File license
    Fair use/fair dealing exception

"Time, it seems, doesn't flow. For some it's fast, for some it's slow.
In what to one race is no time at all, another race can rise and fall..." - The Minstrel

//My video channel//

Reply 9 of 9, by Jo22

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Quick update. I just want to let you know that DOSBox-X has a support for Olivetti/AT&T graphics mode under the name of "DCGA".
https://dosbox-x.com/wiki/Guide%3AVideo-card- … E2%80%90X#_dcga

You select a VGA or VGAONLY machine setting in config file, start DOSBox-X and type DCGA at command line prompt.
That will turn the graphics system into an Olivetti/AT&T compatible mode. I've tested it with latest CGAView X, too.

I think the technical background for this implementation in DOSBox-X is very interesting.
In Japan of the mid-80s, the Toshiba J-3100 laptop had been released.

It was based on the existing 3100 series, which already had 400 line mode support.
More information: https://en.wikipedia.org/wiki/Toshiba_T3100

I can see parallels here to DOS/V (/V=VGA) of the early 90s here: DOS/V also had two select-able display modes.
On MS-DOS version, its very easy to do. Typing "US" will activate English mode, while "JP" will activate Japanese mode.

In a similar fashion, in DOSBox-X, VGA as a machine mode is now being used to provide a selection between
the new Japanese mode (DOS/V with VGA) and the old Japanese mode (J-3100 with DCGA).

Attachments

  • dbx-x_400_cv_b.png
    Filename
    dbx-x_400_cv_b.png
    File size
    65.56 KiB
    Views
    127 views
    File comment
    sample picture
    File license
    Fair use/fair dealing exception

"Time, it seems, doesn't flow. For some it's fast, for some it's slow.
In what to one race is no time at all, another race can rise and fall..." - The Minstrel

//My video channel//

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