VOGONS


Acer 500+ XT system

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Reply 60 of 79, by keropi

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nice, so glad that you got all that from that crappy recording... using a lcd would be better for the camera but I don't know... it doesn't feel right 🤣
If you need something recorded better just say so and I'll try 😀

🎵 🎧 PCMIDI MPU , Orpheus , Action Rewind , Megacard and MK8330 soundcard website

Reply 61 of 79, by Scali

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I've discussed the Moire stuff with reenigne, who wrote that part, and we've come to the conclusion that the speed-dependent nature is not by design, but a bug.
I'll try to do some kind of proper 'unofficial patch' of that part tonight, which should make the music speed constant on all machines, while keeping the code V20-compatible, and not affecting how it looks/sounds on 8088 machines at 4.77 MHz.

We only concentrated on real IBM PCs for the final version, and didn't look into any bugs on systems with other speeds/CPUs. So these bugs slipped past us.

http://scalibq.wordpress.com/just-keeping-it- … ro-programming/

Reply 62 of 79, by keropi

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^ makes sense, so advanced tech stuff are always tied to specific hardware.
I like the idea of the unofficial patch, it will make things better for clones: things might not be 100% but at least the whole demo will run and that's good enough IMHO

🎵 🎧 PCMIDI MPU , Orpheus , Action Rewind , Megacard and MK8330 soundcard website

Reply 63 of 79, by Scali

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Yes, my philosophy is that if there's not a good reason why it shouldn't work, then it should.
And in this case I think I can get it to work (the thing is mainly that the processing speed is critical, worst case I could shave off a row of scanlines to speed it up and make it fast enough, but I'd rather not).
The timing is not too critical, just synchronize on a per-frame basis, 60 Hz.

With Kefrens bars and the endtune it's simple: the timing is far more critical. Kefrens bars needs to be timed exactly to the start of each scanline, so that is roughly 262*60Hz = 15.7KHz, and the endtune needs to be timed to 16.5 KHz sample replay.
This is basically maxing out the CPU, and the timing is done by hand-crafting the code to take an exact amount of cycles. Adding any kind of synchronization, such as polling loops or timer interrupts is going to add a lot of CPU overhead, and suddenly you may need a CPU that is more than twice as fast to do the same effect in a way that it is not directly dependent on the CPU speed.
So there isn't really a way to fix this. The same effects may suddenly require a 286 or more, which defeats the point, and they aren't really the same effects anymore, because they work in a different way.

http://scalibq.wordpress.com/just-keeping-it- … ro-programming/

Reply 64 of 79, by keropi

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^ well you can't have it all 😀 thanks for the explanation on how things work - really a non-freezing demo is just great 😀

in other news regarding the system, I now have +4 working ISA slots, thanks to jwt27 that could part with one of his ISA risers 😀 Tested and working fine.

3GUGhMC.jpg

... and here is roughly how I'll install it in the case, it will be used with small ISA cards that don't need external access - like a XTIDE or a low-tech EMS card... the plan is to have there a xtide and music quest mpu clone with relocated midi-out port.

bYzVlrj.jpg

🎵 🎧 PCMIDI MPU , Orpheus , Action Rewind , Megacard and MK8330 soundcard website

Reply 65 of 79, by jwt27

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Great to see you got the card, and it works! Awesome 😀

I'm still curious why the hacked mainboard part didn't, though...

WANTED - Manuals/drivers for:

  • Tecmar Graphics Master
  • Paradise Autoswitch EGA 350 (EGA1A)

Reply 67 of 79, by Scali

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Okay, here is the 'unofficial patch' of the 8088MPH.003 file: https://www.dropbox.com/s/8xnd7q101w5eay1/808 … PH_003.zip?dl=0
It should fix the V20 and speed issues.

http://scalibq.wordpress.com/just-keeping-it- … ro-programming/

Reply 70 of 79, by keropi

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here's another crappy 😵 recording of the new 003 part. I think it must be OK now, just turn up the volume 🤣
https://www.youtube.com/watch?v=Sj_Myh3G7e8

🎵 🎧 PCMIDI MPU , Orpheus , Action Rewind , Megacard and MK8330 soundcard website

Reply 71 of 79, by matze79

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Any Plans to keep ISA Cards in Place ?

https://dosreloaded.de - The German Retro DOS PC Community
https://www.retroianer.de - under constructing since ever

Co2 - for a endless Summer

Reply 72 of 79, by keropi

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^ I will make something like the plastic holder that cases have for full-lenght isa cards , that's the rough plan

🎵 🎧 PCMIDI MPU , Orpheus , Action Rewind , Megacard and MK8330 soundcard website

Reply 73 of 79, by dacow

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Wow, just saw this thread and can't believe you managed to get this machine in such great condition 😀

This machine holds a special place in my heart being the first machine I ever owned (well was given to me by my uncle). Yours seems to be fully pimped out with 640KB ram whereas mine only ever had 256KB, along the dual 360KB drives. For those in Australia, it came from Dick Smith Eletronics for a princely sum of $799 with a Hyundai hercules monochrome monitor 😀 I didn't realise Acer actually made monitors back then!

My friend who obviously was richer than me had one with a VGA monitor and a 20MB HDD instead of the second floppy drive. I spent many a day pressing CTRL ALT +/- and watching the Hi Speed light turn on and off. Keyboard I always found a bit spongy though!

Excellent work, looking forward to seeing all your extra add on's! 😀

Reply 74 of 79, by Scali

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keropi wrote:

here's another crappy 😵 recording of the new 003 part. I think it must be OK now, just turn up the volume 🤣
https://www.youtube.com/watch?v=Sj_Myh3G7e8

Hum... it seems to run slower for some reason (except when it 'cleans up' at the end), but the music seems to run at the correct speed. I guess it's good enough for a clone 😀
I do wonder what makes it run slower though... especially since the music seems unaffected. The code should be written in a way that the music cannot interrupt the drawing.

http://scalibq.wordpress.com/just-keeping-it- … ro-programming/

Reply 75 of 79, by VileR

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That's an awesome looking system, you lucky bastard 😀 Nice to finally see my "Hard Hat Hack" running on real hardware, heh.

Haven't read through the whole thread yet, but perhaps this will enable you to help me out with this...?

[ WEB ] - [ BLOG ] - [ TUBE ] - [ CODE ]

Reply 76 of 79, by keropi

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@dacow
thanks for the kind words, yeah the condition of the machine is indeed a lucky find!!!!
I'll update the thread as things progress, don't worry 😀

@VileRancour
you Sir, need to make more of them juicy composite color hacks 🤣 , HHM is just great
I can and will help with my Greek rom dumps, I now have 3 cards with roms for you: the ACER cga one and 2 generic MDA ones that were bought locally and thus have Greek charsets as well. I'll upload all 3 in the thread you linked tomorrow, when I get back at my office pc 😀

🎵 🎧 PCMIDI MPU , Orpheus , Action Rewind , Megacard and MK8330 soundcard website

Reply 77 of 79, by VileR

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keropi wrote:

you Sir, need to make more of them juicy composite color hacks 🤣 , HHM is just great

Heh, I have a couple others in mind that I'd want to try, but they'd need more 'advanced' hacking (HHM was just my excuse to "learn" basic [dis]assembly and debugging)... maybe one day if I find the time to practice some more. 😁

I can and will help with my Greek rom dumps, I now have 3 cards with roms for you: the ACER cga one and 2 generic MDA ones that were bought locally and thus have Greek charsets as well. I'll upload all 3 in the thread you linked tomorrow, when I get back at my office pc 😀

Great, that'd be awesome!

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Reply 78 of 79, by filipetolhuizen

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PeterLI wrote:

Cool. I had to remove beepers from my PCs to be able to use them after 7PM. 😀

keropi wrote:

^ exactly, the speaker has the amazing ability to penetrate other rooms when things are silent 🤣 🤣 🤣

I'm so glad that concrete and bricks are still being widely used in constructions here, even between rooms. Anything can penetrate drywalls.

Reply 79 of 79, by kubino

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Very nice system! I got similar system but it comes with 21Mb HDD and one 720Kb floppy. Unfortunately HDD seems have lot of errors. Have to run Low Level format...