Re: VESA mode programming from real mode

Posted on 2021-01-14, 14:07

by

by mpe

in Marvin \ Software

in Marvin \ Software

VBE 2.0 is superset of 1.2. Yes, there is LFB and the new protected mode banking interface for improved performance, but 1.x functions accessed using int 10 are still there. Chances are that if you target 8086 then you are unlikely to be dealing with 2.0 hardware anyway

---

Re: VESA mode programming from real mode

Posted on 2021-01-14, 12:55

by

by mpe

in Marvin \ Software

in Marvin \ Software

It's been a while but as I remember linear framebuffer was preferred mode to use SVGA modes, but optional. It was introduced in 2.0. You should be able to access pixels using banks mapping to 64K windows in real mode address space.

---

Re: FPU daughterboard

Posted on 2021-01-14, 10:08

by

by mpe

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Or that. You can try to call them quoting the part number 😀

---

Re: FPU daughterboard

Posted on 2021-01-14, 09:51

by

by mpe

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

It is not completely unfeasible as the Weitek 3167 is a memory mapped-device which appears to CPU as a block of memory (unlike stack based x87) . However, it would probably have to be a local-bus device as it is a 32bit device sitting on COOOOOOO and VL-Bus wasn't very common on a 386. I've never …

---

Re: Intel PBA 634468-809

Posted on 2021-01-13, 14:52

by

by mpe

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

What is that motherboard? Google returns potentially Intel Zappa (430FX) for that number. That one depending on BIOS should be good until 8GB.

---

Re: Socket 7 CPUs and their voltages

Posted on 2021-01-12, 12:07

by

by mpe

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

SteveC wrote on 2021-01-12, 12:02: The board doesn't do 3.5x unfortunately. Most likely it does. There is no separate 3.5x multiplier. Pentium MMX 233 interpret a 1.5x multiplier as 3.5x, so just set it to 1.5x use 233 MHz CPU and that should be it.

---

Re: ATX2AT Smart Converter - Live on Kickstarter!

Posted on 2021-01-11, 14:40

by

by mpe

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

My setup is 24V/5A DC power source + 80W ATX pico PSU + ATX2AT. Uhm... make sure that PSU is up for the task. 5V was way more important back then as it is now. Can this PSU provide 5A on the 5V line? Yes it can do 6A @5V. Even more peak load. It has its own protection firing at 8.4A. Should be fine …

---

Re: 486 Cache Help & Build

Posted on 2021-01-11, 12:16

by

by mpe

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

it is probably fine and your tweaked results looks fine for average DX4. The cachechk is complaining as there is only a small difference between L2 and RAM is small (26 vs 28 μs), but there is still some. Your RAM is probably as fast as it gets. Depending on your motherboard and SRAM chips, you …

---

Re: ATX2AT Smart Converter - Live on Kickstarter!

Posted on 2021-01-11, 11:41

by

by mpe

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

My setup is 24V/5A DC power source + 80W ATX pico PSU + ATX2AT. Like this But I will try to simplify it and use regular ATX PSU just to be sure.

---

Re: ATX2AT Smart Converter - Live on Kickstarter!

Posted on 2021-01-11, 10:17

by

by mpe

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

I tested ATX2AT on several motherboards I own. At least half of them triggered overload protection immediately after power on. Despite the fact they run normally and they consume about 4-5A on 5V once started. They start just fine when powered using a simple passive adaptor. I use default settings …

---

Re: Mach64 PCI versions - ROM BIOS

Posted on 2021-01-10, 23:52

by

by mpe

in Marvin \ Video

in Marvin \ Video

Yes, the Graphics Pro Turbo 1600 used the 109-33200-x0 boards, just like the one you pictured. http://old.vgamuseum.info/images/stories/palcal/ati/637_p.n.109-33200-10_ati_mach64gx_top_hq.jpg Not sure about board numbers, but I don't believe the card on your picture is Graphics Pro Turbo 1600. 1. …

---

Mach64 PCI versions - ROM BIOS

Posted on 2021-01-09, 15:04

by

by mpe

in Marvin \ Video

in Marvin \ Video

Bought a Mach64 GX PCI card. It comes with VRAM upgrade and it appears to be a Mac Version due to connector setup (DSUB and 15-pin) https://dependency-injection.com/wp-content/uploads/2021/01/DSC_8954-scaled.jpeg It doesn't work in a PC (doesn't even power on screen). I was wondering if I can just …

---

Re: Dallas DS12887 longevity

Posted on 2021-01-09, 14:02

by

by mpe

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Yes. I know about control registers. Arguably I'd expect that in longer term self-discharge of the battery is bigger problem than oscillator drain if you are talking 20+ years. They say the in the active state with the oscillator ticking the device consumes 500 nA (100 nA when inactive). I normally …

---

Re: Dallas DS12887 longevity

Posted on 2021-01-09, 12:44

by

by mpe

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

It was not NOS board. I believe the battery is always connected once manufactured. In datasheet they say the battery life is 10 years. 27 years is remarkable.

---

Dallas DS12887 longevity

Posted on 2021-01-08, 19:02

by

by mpe

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Got Intel Batman motherboard. I was just about to heat up my soldering iron to remove the DS12887 chip, but tried to turn it on first. At it looks like the original Dallas part with 1994 date code is still working. Remembers time / settings just fine between reboots for extended period of time. All …

---

Re: DTK motherboards overall quality level (socket 7)

Posted on 2021-01-08, 10:36

by

by mpe

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Not sure if it could be generalised like that. I remember when I was shopping for a socket 5 motherboard back in 1995 the Soyo was definitely a premium motherboard brand compared to Shuttle I ended up getting. It is true that PCChips and like are usually budget offerings (some exceptions). For other …

---

Re: When did you purchase your first 386 / 486 Computer? Availability vs the early 90's affordability norm.

Posted on 2020-12-31, 15:22

by

by mpe

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

1988 - C64 1992 - 386DX-40 End of 1995 - Pentium 75 I later upgraded the P75 with 200 MHz IDT C6 upgrade and used it until Celeron 300A in 1999 or so. Both were budget self-assembled PCs, but I remember both PCs were quite high spec compared to what people around me usually had.

---

Re: Spring Circle SF586 Socket 5 VLB motherboard

Posted on 2020-12-31, 13:46

by

by mpe

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Non-486 VL implementations are typically not local bus per se (read the CPU is not driving the bus). It is typically a mezzanine bus, just like the PCI. It is asynchronous bus created by the chipset running at VL-Bus compliant speeds. 66 MHz FSB let alone 80 MHz would stretch classic VLB way too …

---

Re: Bought these (retro) hardware today

Posted on 2020-12-23, 17:19

by

by mpe

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Decided to get this Biostar MB-1500PCT motherboard and try to restore it. Kind of above my skillset, but I really want a Pentium/VLB board, and can't really find one for adequate money. Still restoring my $20 SuperMicro P54VL-PCI board. Glad to see another Socket 5 board with VLB. Wow. Nice to see …

---

Re: Bought these (retro) hardware today

Posted on 2020-12-21, 13:44

by

by mpe

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Received the ATX2AT converter device. I missed the original kickstarter campaign but was lucky to receive one of extra units. Here it is with picoPSU power supply which makes it a nice compact combo for running vintage systems https://dependency-injection.com/wp-content/uploads/2020/12/DSC_8846- …

---