Re: Socket 5 - Dallas RTC replacement gone bad

Posted on 2020-12-24, 09:20

by

by jmarsh

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Check if the LEDs on the keyboard do anything at all when powering up the system, also check if the fuse next to the keyboard port has continuity (should have very low resistance, sometimes when they fail they still conduct at a few hundred ohms).

---

Re: Gotek like Optical Driver Emulator - Is it possible?

Posted on 2020-12-23, 08:18

by

by jmarsh

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

It actually mostly works now, but since MSCDEX.EXE and its accompanying drivers don't have the facility to pass through SCSI commands directly MSCDEX command 12 (ioctl output) function 4 is "write device control string"; might be worth checking if any of the atapi device drivers implement it in any …

---

Re: DosBox and OpenSSL

Posted on 2020-12-22, 13:09

by

by jmarsh

in DOSBox Games/Apps

in DOSBox Games/Apps

It's not a DOS program, it's a windows console based program. There is a difference. The OpenSSL.exe itself is telling you that it's a windows program when you try to run it under DOSBox. Just run it directly from windows CMD instead.

---

Re: DosBox and OpenSSL

Posted on 2020-12-22, 12:06

by

by jmarsh

in DOSBox Games/Apps

in DOSBox Games/Apps

DOSBox is for DOS programs only. 64-bit versions of windows can still run win32 programs.

---

Re: Where do I buy the following games?

Posted on 2020-12-20, 04:11

by

by jmarsh

in Marvin \ Software

in Marvin \ Software

GoG only sells the special/remastered versions.

---

Re: How did scrolling work in Keen 4-6?

Posted on 2020-12-18, 19:18

by

by jmarsh

in Milliways

in Milliways

If you watch recordings of CGA gameplay it's noticeably less smooth, the scrolling granularity is at least 4 pixels.

---

Re: Let's talk about our hated trends

Posted on 2020-12-18, 11:42

by

by jmarsh

in Milliways

in Milliways

But I can imagine a scheme were Github just squeezes the vice tighter, and tighter, and tighter, until only established interest can use their platform anymore. Everyone else finds their code flagged as "malicious" by algorithms that are never reviewed by an actual human ever. Might not happen in 5 …

---

Re: How did scrolling work in Keen 4-6?

Posted on 2020-12-18, 11:32

by

by jmarsh

in Milliways

in Milliways

Like his follow-up tweet says, "The second Keen trilogy used a better trick -- just keep panning and redrawing the leading edge, letting the screen wrap around at the 64k aperture edge." So instead of only panning within the width of one tile it pans the width of the whole segment.

---

Re: asrock M.2 VGA card

Posted on 2020-12-15, 00:46

by

by jmarsh

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

DosFreak wrote on 2020-12-14, 21:36: max res is supposedly 1920x1080 but memory is 16mb? I'm guessing they are listing that res due to it's purpose to be used in a server room using smaller monitors. 1920x1080x4 (32bpp) = just under 8MB. They must have been feeling fancy and added another 8MB to …

---

Re: Problem with FIST/FISTP instructions

Posted on 2020-12-14, 23:19

by

by jmarsh

in DOSBox Patches

in DOSBox Patches

Better how ? Just feels a little bit neater/clearer with only one integer comparison against the exponent, since the mantissa value and sign are irrelevant in this case and can be ignored. static void FPU_FST_I16(PhysPt addr) { int exp; double value = FROUND(fpu.regs[TOP].d); frexp(value,&exp); mem …

---

Re: Problem with FIST/FISTP instructions

Posted on 2020-12-13, 21:37

by

by jmarsh

in DOSBox Patches

in DOSBox Patches

Your value for the I64 comparison looks off by one (it's 2^63-1 instead of 2^63), but it probably wouldn't matter anyway since 63 is too many bits of precision to be accurately represented in a double. Using frexp() and checking the range of the exponent might be better?

---

Re: Real hardware DOS gaming console for HDMI displays

Posted on 2020-12-12, 04:21

by

by jmarsh

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

AFAICT GoG do far less work than people give them credit for. Usually their "fixes" for windows games are just bundling freely available directdraw replacements and other community-sourced solutions. If a game has issues with DEP (like Diablo and Warcraft 2 did when they were first released) their …

---

Re: help with soundcard

Posted on 2020-12-10, 15:18

by

by jmarsh

in Marvin \ Sound

in Marvin \ Sound

It's asking what DMA channel to use and from your photo the card is set DMA channel 6.

---

Re: Real hardware DOS gaming console for HDMI displays

Posted on 2020-12-10, 12:00

by

by jmarsh

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

The performance of DOSBox running on a Raspberry Pi is abysmal, it should not be considered a serious option.

---

Re: Real hardware DOS gaming console for HDMI displays

Posted on 2020-12-10, 09:06

by

by jmarsh

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

mothergoose729 wrote on 2020-12-10, 09:02: an x86 ARM based SOC A what now?

---

Re: Real hardware DOS gaming console for HDMI displays

Posted on 2020-12-10, 06:29

by

by jmarsh

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Jazz Jackrabbit is not a 320x200 game, it's a 320x240 game (square pixels) that uses letterboxing to achieve an active display area of 320x199.

---

Re: Real hardware DOS gaming console for HDMI displays

Posted on 2020-12-10, 01:28

by

by jmarsh

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Even with VT-d current CPUs can execute basic instructions differently from older CPUs if undefined behaviour is invoked, which some games rely on.

---

Re: What is good puzzle design in adventure games?

Posted on 2020-12-05, 16:27

by

by jmarsh

in Milliways

in Milliways

Good example of a terrible puzzle is near the end of Police Quest 4, where Spoiler you get into the bad guy's "lair" not by using any sort of police work, but by going to an unrelated location and chasing a loose dog that just happens to appear.

---

Re: dynrec vs. secure platforms - opinions wanted

Posted on 2020-12-05, 16:23

by

by jmarsh

in DOSBox Development

in DOSBox Development

Apparently the dosbox-x guys are also experimenting along similar lines, if I correctly interpret what I saw in their repository. Yes, obviously they were "inspired" by me mentioning memfd_create and how to use mach_vm_remap . A shame it was rather rushed and not discussed here like I suggested as …

---

Re: dynrec vs. secure platforms - opinions wanted

Posted on 2020-12-05, 13:11

by

by jmarsh

in DOSBox Development

in DOSBox Development

Apparently rather than discussing possible solutions, other people just want to be told what works so they can slap it in their project and take credit for figuring it out.

---