Re: Intrest in new ISA cards?

Posted on 2025-04-21, 05:06

by

by kdr

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

thisisamigaspeaking wrote on 2025-04-20, 15:13: Graphics Gremlin HDMI with an FPGA with more LEs (maybe just the 8k version of the one used there). Interesting trivia: I have heard that the ICE40HX4K chip actually has the 8K die inside, and icestorm should be able to program it with an 8K bitstream …

---

Re: Drivers library CD from 1997 retrieved in my personnal collection

Posted on 2024-07-07, 00:30

by

by kdr

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

3dfxpowa wrote on 2024-07-06, 17:57: Just finished to upload the disc, ISO format 😀 https://archive.org/details/drivers-97 Very nice! Here's the link to browse/download the individual files on the ISO: https://archive.org/download/drivers-97/DRIVERS97.ISO/

---

Re: IBM PC Cassette Interface... as a sound card??

Posted on 2024-07-07, 00:25

by

by kdr

in Marvin \ Sound

in Marvin \ Sound

In fact, given the circuit design, you could make the case that the PC designers looked at their circuit for the cassette interface and thought "why not add an internal speaker to it?" since it only took a couple of extra logic gates and a repurposed line driver IC....

---

Re: IBM PC Cassette Interface... as a sound card??

Posted on 2024-07-05, 04:11

by

by kdr

in Marvin \ Sound

in Marvin \ Sound

t Regardless, I'm more interested in the use of the cassette port for sound. Was it higher fidelity than the PC speaker because it didn't have the same limitations as the PC speaker circuit? Or was it about the same? On the original IBM PC, the PC speaker and the cassette port were both driven by …

---

Re: Question about HP t5710 Voltage Tolerance

Posted on 2024-06-10, 03:53

by

by kdr

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Of interest is that the later HP t5740 is actually spec'd for 19V and uses the same connector as the HP laptop power supplies. I picked up my t5740 without a power supply and it was easy to find a compatible power supply for it. (This thread did inspire me to go check the t5740's spec sheet to make …

---

Re: ALTERA MAX7000 adventure to program old CPLD's

Posted on 2024-06-01, 05:04

by

by kdr

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

I've always been interested in the old ALTERA software, but never managed to get my hands on a copy. Is there a "schematic capture" mode (where you can design using 74xx style logic) or a floorplanner style mode where you can view/edit the placement and routing? The 7000 series were quite small by …

---

Re: Live-booting a HDD-less Pentium4 laptop to backup floppy disks.

Posted on 2024-02-18, 08:52

by

by kdr

in DOS

in DOS

Hiren's Boot CD (verison 10.6) is full of vintage DOS and Windows utils from the P4 era, it has a live Mini XP and a live mini Linux which are both loaded with useful programs. It's my go-to disc for any retro machine with a BIOS new enough to boot from CD-ROM. Easy enough to find a copy of Hiren's …

---

Re: Purpose of negative horizontal sync polarity on EGA(/(S)VGA) cards?

Posted on 2024-01-28, 20:17

by

by kdr

in PC Emulation

in PC Emulation

Won't the HSYNC polarity being negative clash with detecting HSYNC itself? Since it needs to go high every hsync period to properly cause flyback of the beam? Most of the early VGA monitors have a clever sync detection circuit that uses a combination of XOR gates and one-shot timers which detects …

---

Re: VGA behavior when V. Display End >= V. Retrace Start

Posted on 2024-01-27, 03:38

by

by kdr

in Marvin \ Video

in Marvin \ Video

Just before the holiday season, I was playing around with improper VGA modes in an attempt to reload the CRTC start address multiple times per frame. I was doing my experiments on an old 286 with an integrated Paradise PVGA1A chipset. I was planning to do further work before writing it up, but Real …

---

Re: What retro activity did you get up to today?

Posted on 2023-12-22, 19:33

by

by kdr

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Today I go to the post office to pick up the order and this woman brings out 2 boxes taped together that looks waaaaaay too large to be just 2 boxes of 10 floppy disks. long story short, turns out what I bought was 10 packs of 10 disk, twice, so 200 disks in total. :) I'm not complaining and I …

---

Re: MT-32 and SC-55 music composition & sound effects / keyboards / midi

Posted on 2023-12-14, 19:50

by

by kdr

in Marvin \ Sound

in Marvin \ Sound

Does Sequencer Plus and the keyboards you mentioned specifically support the MT-32? I have a feeling that finding support for the SC-55 will be easier, given the 80s dates for the MT-32, though it would be cool top learn how the composers at Sierra made all of those great MT-32 tracks. From the …

---

Re: MT-32 and SC-55 music composition & sound effects / keyboards / midi

Posted on 2023-12-09, 22:12

by

by kdr

in Marvin \ Sound

in Marvin \ Sound

What I am asking is for information on midi controllers / keyboards and period-correct apps which support both the MT-32 and the SC-55, and be able to use it on any retro system, real and emulated. Voyetra's Sequencer Plus GOLD is an early 90s MS-DOS application that supports loads of MIDI …

---

Re: Bought these (retro) hardware today

Posted on 2023-12-09, 19:51

by

by kdr

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Yesterday I bought a carton of 500 floppies... individual packs of ten 1.44MB 3.5" diskettes, new old stock that's still sealed! They appear to be fairly ancient relics, the blurb on the back of each pack proudly proclaims that they are factory formatted "for IBM PS/2's and other systems (model 30 …

---

Re: 90s Era MIDI keyboards for PC Market

Posted on 2023-06-14, 04:57

by

by kdr

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

I'm looking to get a MIDI keyboard of the style common for PC use in the 90s. Hopefully you know the style: white/gray, usually relatively small 32

---

Re: Unable to boot IBM PC (5150) with a Gotek emulator and FlashFloppy

Posted on 2023-06-14, 04:12

by

by kdr

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

I'm trying to boot my IBM 5150 from a Gotek emulator, running the latest FlashFloppy firmware (3.39). The gotek drive appears to be detected on boot (no errors), and there is a short seek, but then the PC goes to basic instead of booting. The oled display shows that the drive quickly seeks up to …

---

Re: 8088 Interrupt delay timing

Posted on 2023-05-21, 01:48

by

by kdr

in PC Emulation

in PC Emulation

I thought it might be due to a microcode loop (the similar WAIT instruction is explicity documented as checking the /TEST pin every 5 clocks) but apparently not; reenigne's disassembly of the 8086 microcode page has this to say: There is no microcode for the segment override prefixes (CS:, SS:, DS: …

---

Re: Original IBM EGA card repair thread

Posted on 2023-05-18, 09:15

by

by kdr

in Marvin \ Video

in Marvin \ Video

Once you've checked the basics on the card (correct voltages, no shorts) a good next step would be to determine if the video BIOS on the card is readable / intact. My go-to method for this is to just load up DEBUG.EXE and use the "D C000:0" command to dump the first 128 bytes of the VBIOS. I usually …

---

Re: CGA "phantom" vsyncs: glitch-testing the 6845 CRTC

Posted on 2023-05-06, 09:46

by

by kdr

in Marvin \ Video

in Marvin \ Video

Very interesting! Inside the 6845 there will be a register or latch which holds the current value of R7, and this is fed to a comparator whose other input comes from the vertical counter. The comparator will be purely combinatorial logic. As the inputs to the comparator change, the various logic …

---

Re: targeting PC DOS 1.0 - how do you open files?

Posted on 2023-04-25, 00:08

by

by kdr

in Marvin \ Software

in Marvin \ Software

PC DOS 1.x is a very primitive (and simple) environment. It was a slightly more polished version of 86-DOS, which was originally designed (by Tim Paterson at SCP) to be a kinda-clone of CP/M which ran on the 8080/Z80 machines. It's just about possible to use a CP/M developer's manual to write a DOS …

---

Re: CRT randomly makes popping noise

Posted on 2022-12-21, 06:41

by

by kdr

in Marvin \ Video

in Marvin \ Video

It could just be a bit of dust/moisture from sitting in storage for a long time. I picked up a CRT that was in good working condition, great picture, but had obviously been in storage for a loooooong time. It made a lot of snapping/popping noises when first powered on, but over the next 5-10 hours …

---