Re: Is this a fake Lemmings disk?

Posted on Today, 00:02

by

by mkarcher

in Marvin \ Software

in Marvin \ Software

2. I tried to mount it on my linux computer using a USB floppy drive and it couldn't read it. Putting it in my 720k drive on a real DOS computer works just fine. 3. I initially tried to run the game using the "CGA" and "IBM PS/2" options because I'm running it on a IBM PS/2 with the onboard MCGA …

---

Re: ET4000AX variants

Posted on 2021-03-04, 23:06

by

by mkarcher

in Marvin \ Video

in Marvin \ Video

the ramdac was originally a look up table to convert 256 palette colours into R/G/B values. once you leave 8bpp your leaving half the function of the chip behind. In other words, RAMDAC in modes greater than 8-bpp doesn't use the RAM section, only the DAC. Not necessarily. In 15/16bpp modes, you …

---

Re: Deskmaster 486 Cache...

Posted on 2021-03-04, 22:57

by

by mkarcher

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

You seem to have confusing sources. The board in that computer only provides a single bank of cache. The cache sockets have 28 pins. The biggest cache chips that fit into 28-pin sockets are 32kx8 chips. There are 64kx8 and 128kx8 chips, but they come in 32-pin cases, not 28-pin cases. A single bank …

---

Re: Help identifying an old ISA 8bit card

Posted on 2021-03-04, 21:35

by

by mkarcher

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

That's tough if you try to recover the function of the card from that lousy image. I guess you don't have access to the hardware yet, so you won't be able to provide a better picture. Some things can be recovered from that image, though: The big Intel chip at A/B 63-83 is likely a micro-controller. …

---

Re: Best and worst sound cards you have ever owned?

Posted on 2021-02-26, 21:30

by

by mkarcher

in Marvin \ Sound

in Marvin \ Sound

I was surprised to see the AD1816-based cards get so much hate. I bought one (a board called TT-AD1816, likely a OEM edition of the Terratec Base 1) in 2000 for 10€ or less new, and it worked like a charm in linux, with arbitrary sample rates between 5kHz and 55kHz, and even full duplex. The DOS PnP …

---

Re: Warning: Leaking BIOS/CMOS/Resume Batteries Damaging Laptops

Posted on 2021-02-26, 20:42

by

by mkarcher

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

My copy of a COMPAL BC380 came with severe battery damage from the CMOS/resume battery pack. In this case, it was 4 AAA NiCd cells in the front next to the floppy drive. I had to fix some traces on the keyboard. I already got new cells, but I didn't yet get around to install them.

---

Re: [Super EGA-120] PC Magazine Volume 5 Number 15 Project

Posted on 2021-02-24, 20:32

by

by mkarcher

in Marvin \ Video

in Marvin \ Video

This is a very cheap project ($10 - $20 after shipping), and easy to build. You may even have all the necessary parts on hand if you have protoboard laying around. Obviously you'll need a standard EGA graphics adapter and monitor to use this. The idea of this adapter is that the EGA core chip can …

---

Re: Custom made, 50ns, FPM, Simm 30, memory modules with parity.

Posted on 2021-02-24, 20:01

by

by mkarcher

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

How are there problems ? There's exact same amount of CAS pages and thus refresh cycles between the two organizations. While the addressing scheme looks like there is the exact same amount of CAS pages, the internal organization is different. It is very common for 1M x 1 chips to be internally …

---

Re: Do you want an EGA monitor?

Posted on 2021-02-23, 22:33

by

by mkarcher

in Marvin \ Video

in Marvin \ Video

And what exactly speaks against 60Hz in a 400 line mode (or scan-doubled 200 line mode) on a VGA card? Wouldn't that be what you get when you use the 480 line mode's sync settings? I once had a TSR that enabled to do things like just this. I used it to play 200/350/400 line games where the 286-12 …

---

Re: What is this empty socket for?

Posted on 2021-02-13, 21:35

by

by mkarcher

in Marvin \ Video

in Marvin \ Video

Usually, an empty socket on late MDA/CGA clones is meant to take a character ROM that can be used instead of the integrated CP437 ROM. Thanks. Is this just for foreign languages? Or are there roms with graphics characters available? I never heard of alternate DOS fonts ("codepages") with more …

---

Re: What is this empty socket for?

Posted on 2021-02-11, 20:31

by

by mkarcher

in Marvin \ Video

in Marvin \ Video

Usually, an empty socket on late MDA/CGA clones is meant to take a character ROM that can be used instead of the integrated CP437 ROM. The integrated graphics chips usually has a pin that chooses between internal and external ROM. If the manufacturer of your card invested into a DIP socket for the …

---

Re: 8-bit guy gets ultra-rare NOS IBM (prototype?) from Computer Reset then proceeds to obliterate it

Posted on 2021-02-11, 20:25

by

by mkarcher

in Marvin \ Video

in Marvin \ Video

DOSBox-X developer here: I have a PS/2 model 25 with MCGA and I can confirm that booting the system without a monitor attached triggers this 15KHz mode very reliably. 640x480 is non-functional, all other modes act appropriately. I have some MCGA study notes here for DOSBox-X's machine=mcga …

---

Re: Memory card with "stacked" dram chips: I don't understand how this works

Posted on 2021-02-09, 17:43

by

by mkarcher

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

they're probably two slightly different chips It is a different part number on the top chip vs. the expansion daughtercard. Maybe you're right. Most DRAM chips have the bits in a square matrix of rows and columns, where both the row count and the column count is a power of two. So you can get 4k, …

---

Re: How to modyfy SOYO SY-4SAW2 to take Lithium Cell, instead of Nickel rechargeable. Bios upgrading.

Posted on 2021-02-06, 11:39

by

by mkarcher

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Now, I was putting together a diagram and noticed that after going thorough the resistor, the +5v line also goes to other components, aren't those components expecting the +5v line that has been cut off? I was able to trace that to a couple of tantalum caps and from there to a resistor array, I …

---

Re: 40 Pin Floppy Cable Isssues

Posted on 2021-02-06, 08:11

by

by mkarcher

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Sorry, I wasnt thinking when I posted....it is a 34 Pin Floppy cable........ The cable has the twist in it, both of them do....not sure what is up....its multiple boards and multiple floppy drives as well..... Are you aware that there is not just two possibilities to orient the cable, but four? Not …

---

Re: Please help to identify this module

Posted on 2021-02-02, 22:05

by

by mkarcher

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

It *could* be system RAM, but the combination of such a low quantity with a 32b wide bus would be odd, no 386 upgrade would just do 1MB, even back in 1991. I dont think it is 32bit wide. With parity, that would be 36 pins just for data. The connector is clearly labeled as 40 pin connector, so this …

---

Re: Device (s) using this INT: PR...

Posted on 2021-02-01, 16:47

by

by mkarcher

in Marvin \ Software

in Marvin \ Software

Why am i getting this error upon boot? And how do i fix it? This question has too little context to get a good answer. It looks like the beginning of a status message, followed by some garbage characters. If your systems hangs at that point, it most likely crashed, and the garbage characters are …

---

Re: pkzip 2.04 locking up pc - what could be causing this?

Posted on 2021-02-01, 16:41

by

by mkarcher

in Marvin \ Software

in Marvin \ Software

The "floppy" install disk was actually just my GoTek USB key floppy, so I don't know if that would be causing the errors, however I agree maybe the download from WinWorldPC was bad, would make sense that it's locking up. Do you know if I zip a file using Windows 10 built in compression, if any …

---

Re: pkzip 2.04 locking up pc - what could be causing this?

Posted on 2021-02-01, 16:15

by

by mkarcher

in Marvin \ Software

in Marvin \ Software

To install PKZIP, I just copied all the files from the PKZIP Install Floppy to a folder on C: \pkzip as I did try to run the Install.bat file on the floppy but it just threw out a tone of errors about not being able to find files. The ton of errors might be an indication that the copy of PKZIP, as …

---

Re: Openwatcom integer arithmetic overflow strangeness

Posted on 2021-01-31, 12:10

by

by mkarcher

in Marvin \ Software

in Marvin \ Software

Most of my C knowledge comes from a unix background (started back in the 90's on Sun OS, then IRIX, various BSD's and Linux), so the vagaries of some of the restrictions on machines with a 16bit word size are new to me. It's exactly the same rules you have on 32 bit systems if you want to do 64-bit …

---