Re: FM synth - native/direct vs. through MIDI?

Posted on 2023-09-15, 12:47

by

by vstrakh

in Marvin \ Sound

in Marvin \ Sound

In the DOS era there was not much MIDI-capable hardware, and it definitely was not meant to interface FM synths. The dos games would play game-specific music formats via game- or game engine-specific driver (AIL, MIDPACK, etc). The driver would normally access OPL hardware directly, though later …

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Re: VGA mode 13 no signal on real hardware

Posted on 2023-09-14, 06:51

by

by vstrakh

in Marvin \ Video

in Marvin \ Video

On multiple occasions - with different cards and motherboards - I've seen "signal out of range" warning from monitor when switching between text and graphic modes. And it was always fixed by re-seating video card or changing the slot it was installed into. This issue could be related. The bad …

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Re: Which old programming languages do you still use/play with today->

Posted on 2023-09-06, 17:59

by

by vstrakh

in Milliways

in Milliways

Forth. Really old, but compact and fits really well when put into synthesizable hardware.

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Re: Collection rationale

Posted on 2023-08-03, 13:20

by

by vstrakh

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

rasz_pl wrote on 2023-08-03, 12:49: Spectrum/Amstrad/Atari ST sound is a crime against humanity, Im sure Geneva Convention mentions it. It's a heritage. And anyway, it's more of a challenge on how ridiculously small I can pack it 😀

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Re: Collection rationale

Posted on 2023-08-03, 12:19

by

by vstrakh

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

assumed that a boolean gate would be equal to 3 transistors (I think AND gate takes 3 transistors, again from my memory, might be more or less but the ballpark is right). It's not about how many transistors are needed per boolean gate. LE's are not boolean gates, and your "ballpark estimation" has …

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Re: Collection rationale

Posted on 2023-08-03, 11:50

by

by vstrakh

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Latency would only matter if you interfaced software emulated part with real hardware, and even then its not a problem with sufficiently fast emulation, as evidenced by MCL65+ and MCL86+. Nah, just playing old games of 286-era, dosbox slows down when moving the mouse over the screen, the PIT …

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Re: Collection rationale

Posted on 2023-08-03, 11:47

by

by vstrakh

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

It was a ballpark figure to gauge the practicality to fit pentium core on DE10. But you had to have some picture in your mind to justify this comparison, some hard numbers on how transistors count maps to logical elements? Let's look at it from the different angle. Say, can you tell any numbers …

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Re: Collection rationale

Posted on 2023-08-03, 10:20

by

by vstrakh

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

is there any reason to not to implement it on software instead of the much more cumbersome fpga? The latency is the answer. FPGA delivers well defined signals, ideally equal to the real hw, though internally the mechanics might differ. A software not only can't do low latency, it can't even …

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Re: Collection rationale

Posted on 2023-08-03, 10:18

by

by vstrakh

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

That's why on FPGA you implement the resulting higher-level functionality, and don't model each individual transistor or gate equivalent. I never claimed such. But you didn't you say that "pentium on de10 is impossible because of 110000 Y vs 3000000 Z". Technically you don't implement anything on …

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Re: Internal Error

Posted on 2023-08-03, 09:31

by

by vstrakh

in DOSBox General

in DOSBox General

From the programmer's point of view, the "String Space Corrupt" error message might indicate there is some kind of collection/database of strings, and that collection/database is damaged in some way, like maybe bits flipped during copying from floppy, etc. The app had checked the CRC/hash, or found …

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Re: Collection rationale

Posted on 2023-08-03, 09:17

by

by vstrakh

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

doublebuffer wrote on 2023-08-02, 23:20: DE-10 has 110,000 logic elements. Pentium has 3,100,000 transistors. Althoug a logic element is composed of at least 3 transistors, That's why on FPGA you implement the resulting higher-level functionality, and don't model each individual transistor or gate …

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Re: Collection rationale

Posted on 2023-08-02, 08:25

by

by vstrakh

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

appiah4 wrote on 2023-08-02, 08:08: Doesn't the MİSTer basically do this already? I guess the expectation is the ability to freely mix and match the components. MiSTer provides the whole system, but does not let user who is not experienced FPGA designer to replace one piece (like the video/audio …

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Re: Gotek woes (32KB) - anyone else?

Posted on 2023-07-24, 08:47

by

by vstrakh

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Floppy uses DMA. It's not the floppy drive, but floppy controller who uses DMA. Whatever issues that might be related to CPU/bus speed - those shouldn't leak into the floppy drive side, so no point suspecting the system speed as the cause of problems for the floppy drive. So either you suspect …

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Re: Gotek woes (32KB) - anyone else?

Posted on 2023-07-24, 08:29

by

by vstrakh

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Maybe it's also because of the quickness of that 286. It runs at 16 MHz (CPU), with everything else at zero wait state. Isn't this detail is abstracted by the floppy controller? The floppy drive itself has nothing to do with the CPU or ISA bus at all. The controller may have issues though when …

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Re: WinFast A250 Ultra: help identifying a missing diode (?)

Posted on 2023-07-22, 14:51

by

by vstrakh

in Marvin \ Video

in Marvin \ Video

Aaahha, the post from 2012: https://www.elektroda.pl/rtvforum/topic2344842.html Same issue, diode is missing and the three swollen caps replaced :) Googled more pics from Czech store, It is L42 indeed: https://kobra.odkarla.cz/t2/1080x1080/b1/73/graficka-karta-leadtek-winfast-a250-ultra/graficka- …

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Re: WinFast A250 Ultra: help identifying a missing diode (?)

Posted on 2023-07-22, 14:40

by

by vstrakh

in Marvin \ Video

in Marvin \ Video

Looking at the datasheet of that IC (a voltage regulator) it looks like that diode should be a schottky diode. Googling the "L42 shottky" finds the BAT54A part, and the number shows the arrangement of individual diodes inside the package: https://pdf1.alldatasheet.net/datasheet-pdf/view-marking/ …

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Re: Paradise EGA Capacitors and Composite

Posted on 2023-07-20, 15:51

by

by vstrakh

in Marvin \ Video

in Marvin \ Video

Yes. I'd say that was the "rule of thumb" back then. I've just looked through a bunch of old videocards, Trident, CHIPS, etc. Every single one had a single nominal of 10uF 16v tantalums used all over the board. Only the ancient Jovian Logic RUBY 451 used smaller 4.7uF 16v for the same purpose, and …

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Re: Paradise EGA Capacitors and Composite

Posted on 2023-07-20, 12:58

by

by vstrakh

in Marvin \ Video

in Marvin \ Video

16v are ok for 5v rails. For 12v rail having 16v capacitor is not that great, there are recommendations on derating the caps, many debatable though, as current quality of tantalums is way higher than before. But it's safer to put higher voltage rated caps on 12v rails. The size of current 25v/35v …

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Re: Paradise EGA Capacitors and Composite

Posted on 2023-07-20, 08:02

by

by vstrakh

in Marvin \ Video

in Marvin \ Video

Those are bulk caps, their exact capacitance is not that critical for the application, just make sure you have the voltage rating above the rails they're sitting on. Most likely you won't even be able to find lower voltage caps (assuming you'll be replacing it with tantalums to maintain the original …

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Re: [Research] I have a beautiful CT2230 (Sound Blaster 16) on hand, however it needs a repair. Maybe capacitors?

Posted on 2023-07-19, 07:17

by

by vstrakh

in Marvin \ Sound

in Marvin \ Sound

Don't limit your tests to electrolytic caps only. Yes, they degrade, but it's also likely that some MLCC can be damaged by inappropriate handling of the card. I had my SB16 CT2940 fixed, replacing ceramic caps that had hairline cracks: Sound Blaster 16 (CT2940) PCM sound too quiet, FM ok [repaired: …

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