Re: Edsun CEG (Continious Edge Graphics) RAM DAC

Posted on 2023-06-07, 02:10

by

by jmarsh

in Marvin \ Video

in Marvin \ Video

At the very least it should act as a normal 8-bit color RAMDAC if it is truly a drop in replacement. To get the Anti Aliasing features, you need to include that logic in your graphics code. Too bad it is not automatic, but we are talking 1990 technology after all:) The ebay listings say they're …

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Re: XTA to ATA bridge: is it possible?

Posted on 2023-06-02, 19:59

by

by jmarsh

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

There is no need. Connect them to an 8-bit controller like they were designed for, then plug that controller into any ISA slot. The card's BIOS will hande the rest.

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Re: ISA Blaster: A software-defined ISA Card

Posted on 2023-06-01, 08:46

by

by jmarsh

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Disagree, because in that case you still need a separate floppy controller which defeats the purpose of the proposed "all in one" card. And that code is hardly portable to generic hardware...

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Re: ISA Blaster: A software-defined ISA Card

Posted on 2023-06-01, 04:18

by

by jmarsh

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

A card wouldn't need to connect to several slots; they're all part of a bus, the signal lines are connected in parallel. The "easy" way to emulate a floppy drive is by emulating the controller itself rather than the drive.

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Re: com file loading higher than expected

Posted on 2023-05-29, 21:24

by

by jmarsh

in DOSBox Games/Apps

in DOSBox Games/Apps

The code should begin at the very start of the .com file, those first 256 bytes of zeros should not exist.

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Re: Toshiba Satellite Pro 430CDS Windows 2000 Downgrade

Posted on 2023-05-29, 17:06

by

by jmarsh

in Marvin \ Software

in Marvin \ Software

These old Toshiba laptops used "removable" floppy drives that shared the same bay as the CDROM. If you wanted to use both at the same time, there was an external caddy that held the floppy drive and attached to a port. Most likely this unit's floppy drive is still in that caddy tucked away forgotten …

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Re: Wolfenstein 3d: CODE column on High Scores screen

Posted on 2023-05-29, 00:29

by

by jmarsh

in Marvin \ Software

in Marvin \ Software

At some point in time there was going to be a competition for highest score, the code (shown only for the top score) is a verification value like a checksum. Guessing the cheat codes probably don't work on that version?

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Re: com file loading higher than expected

Posted on 2023-05-28, 23:51

by

by jmarsh

in DOSBox Games/Apps

in DOSBox Games/Apps

Post the source code (or at least the beginning where you set the origin).

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Re: "Input not supported" error when resolution set to 800x600 256 color

Posted on 2023-05-28, 20:21

by

by jmarsh

in Marvin \ Video

in Marvin \ Video

I think the app is lying to you and configuring for 800x600x256 interlaced rather than non-interlaced.

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Re: "Input not supported" error when resolution set to 800x600 256 color

Posted on 2023-05-28, 19:27

by

by jmarsh

in Marvin \ Video

in Marvin \ Video

None of the frequencies in the left column produce an image at all on the LCD?

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Re: "Input not supported" error when resolution set to 800x600 256 color

Posted on 2023-05-28, 19:07

by

by jmarsh

in Marvin \ Video

in Marvin \ Video

How do you know those frequencies are supported for that board? They are rather high for an old ISA card. Typically the pixel clock for 800x600@60fps would be 40MHz...

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Re: Problem with Windows 98 and DMA

Posted on 2023-05-28, 15:55

by

by jmarsh

in Windows

in Windows

Eimer wrote on 2023-05-28, 15:30: I cannot use a 80 PIN cable because they all have a blocked pin in the middle, mobo has all pins so I cannot connect it. The 430TX only supports up to UDMA/33 which doesn't require an 80 pin cable.

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Re: "Input not supported" error when resolution set to 800x600 256 color

Posted on 2023-05-28, 15:10

by

by jmarsh

in Marvin \ Video

in Marvin \ Video

Beside this, I really don't understand the logic behind it. When the card output 640x480 256 color to the LCD, the LCD detects that the refresh rate is exactly 59hz. What in the earth is the reason that it can output 59hz when in 640x480 but can not do the same in 800x600 mode. It's only 3hz lower …

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Re: PicoMEM : Pi Pico on ISA, with full Memory and I/O bus access

Posted on 2023-05-24, 13:51

by

by jmarsh

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Can't deny the Pi Pico is nice and cheap, but for a multi-purpose ISA device (RAM, disk, USB, audio, network...) I think there are much easier/better options. My pick is the Teensy 4.1; a 600MHz cpu, 8MB of onboard flash (minus storage required for code), two USB host/device ports, SD slot, 100mbit …

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Re: Palette inverted when using a VLB video card and Sound Blaster and compatible cards

Posted on 2023-05-23, 14:44

by

by jmarsh

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

ViTi95 wrote on 2023-05-23, 14:21: The palette is copied to the video card via OUT instructions (ports), so memory overlapping shouldn't be a problem. I would suspect an issue with the AEN signal getting to the video card, causing it to misinterpret the DMA transfers to the sound card as port …

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Re: Palette inverted when using a VLB video card and Sound Blaster and compatible cards

Posted on 2023-05-23, 14:05

by

by jmarsh

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Do the colors shift while digital audio is playing, or do they stay the same constantly wrong colors?

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Re: Intel publishes a white paper on x86S, a 64-bit only architecture

Posted on 2023-05-21, 14:30

by

by jmarsh

in Release Announcements

in Release Announcements

64-bit operating systems will still run 32-bit apps exactly as they already do, there aren't any changes to that.

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Re: How will this affect DOSBox development?

Posted on 2023-05-21, 11:31

by

by jmarsh

in PC Emulation

in PC Emulation

IIRC there are some 16-bit addressing instructions generated by the x86_64 dynamic core but the PDF says they are unaffected.

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Re: ide cf adapter udma 66/100 compatibility flop

Posted on 2023-05-21, 02:18

by

by jmarsh

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

how authoritative is that diagram? if i read it correctly there's no difference between the blue and black connectors--at least in the cables that employ the cut wire method. In addition to the PDIAG signal being cut, it's also probably connected to ground inside the blue connector (which is a good …

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Re: Intel publishes a white paper on x86S, a 64-bit only architecture

Posted on 2023-05-20, 14:05

by

by jmarsh

in Release Announcements

in Release Announcements

They more or less have dropped x87 and coders/devs are told not to use it for any new applications. MMX is gone entirely from modern hardware, but was folded into AVX, so it can sort of still be used, with code modifications. It's not gone at all. MMX registers still share the same space as the 80- …

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