Re: Add -5V directly to ISA pin B5 - is it safe?
Posted on 2023-01-11, 09:36
Isn't it exactly the same as some ISA board mentioned elsewhere on the vogons, hosting 7905 regulator, taking -12V from ISA connector and feeding -5V back into connector?
Re: On a multi video card computer, how do you detect what's the "Primary Display Driver"?
Posted on 2022-12-07, 20:05
If it's the Optimus tech, then integrated Intel video is always primary. Nvidia GPU will kick in when the driver recognizes the app's need in powerful 3D, but Intel GPU will present final image on screen. See Nvidia control panel for lists of known 3D apps, you can add your app there to force Nvidia …
Re: How to install 3c87-40 coprocessor for 386dx?
Posted on 2022-12-03, 16:58
My mobo has different orientation, but socket's pin 1 is clearly marked on the silkscreen. Same bump for pin 1 on FPU. Filename iit_npu.jpg File size 377.82 KiB Views 123 views
Re: does this code change the 16 color EGA/VGA palett, how is the color defined?
Posted on 2022-12-02, 12:15
Question 1: what is a secondary blue/mono video bit and a green/intensity video bit? EGA has 6-bit digital output, the secondary values is the least significant bit in each channel's 2-bit value, carrying 1/3 of channel value weight, and primary carrying 2/3 of the weight. The monochrome display …
Re: DOS C interface to asm function?
Posted on 2022-11-22, 18:31
Really, you should check with docs for the actual compiler you will be using, since there are no "standard C libraries" outside of the context of specific compiler's environment. Bitsavers has manuals (user and reference guides) for many tools from Borland for sure.
Re: DOS C interface to asm function?
Posted on 2022-11-22, 18:06
You can write programs with whatever conventions available from your compiler, but you must stick to the original conventions used in the libraries you're trying to replace. And fastcall was not standardized anyway. It can differ across the compilers, so there's no point in using it in public APIs. …
Re: DOS C interface to asm function?
Posted on 2022-11-22, 16:33
As far as I know there is no fastcall conventions in Turbo C. It did appear in Borland C++ (Turbo C++?), but that's past the Turbo C lifetime.
Re: Help identify this CGA/EGA card
Posted on 2022-11-21, 09:23
Grzyb wrote on 2022-11-21, 09:03: No, it's just a character generator. Ah, true for MDA. I was carried away with EGA suggestion.
Re: Help identify this CGA/EGA card
Posted on 2022-11-21, 07:20
If you have EPROM programmer you'd better read out the ROM, the strings in it might give some hints.
Re: Trying to build a 486 computer, are all my mobos dead or am i doing something wrong?
Posted on 2022-11-18, 17:39
Did you close the switch that starts ATX psu (PS_ON# to GND)? I don't remember how the Pico-PSU behaves, but I'd expect it to do the same as normal PSU does. And I see some hanging wires with the clips that should go into the switch.
Re: L2 cache for 386/486/Pentium
Posted on 2022-11-17, 17:29
For my 486 I had 12ns Renesas IDT71256SA (28 pin 32k x 8 ) ordered on Mouser, it was ~3.x€/piece when it was available (out of stock now).
Re: SMARTDRV and controller with cache.
Posted on 2022-11-16, 07:56
Cache controller accelerates disk operations with hdd plate(s). .. While SMARTDRV (or other cache-utilities) accelerates file-system operations. Unrelated but very similar example - the 286 CPU has 6-byte FIFO for instruction bytes, same as the earlier 8086. But it also has a FIFO for 3 decoded …
Re: post dignostics cards
Posted on 2022-11-14, 17:25
The ones on the right quite often has bad solder joints. I've bought few cards advertised as damaged, hoping to recover the Altera CPLD. All of them had bad solder work on LED indicators, and on the one card the LED indicator just fell off the board :) The one on the left seems more useful. It has …
Re: How to filter out very high frequencies with a circuit?
Posted on 2022-11-13, 09:27
mkarcher wrote on 2022-11-12, 20:04: I guess it's supply ripple caused by periodic current spikes. This is likely to be a specific frequency, Then the fact that switching frequency has dropped into audible range, way below normal operating conditions, could indicate that the voltage regulator was …
Re: HELP Save my Hard drive.
Posted on 2022-11-12, 18:53
If you believe the bad sectors are mistake done by scandisk because of some intermittent issues (bad PSU, bad contacts in cables), then you can try to format the disk with 'format', just do not use quick format. There should be command line option about retesting the bad sectors (/C). Sure only …
Re: HELP Save my Hard drive.
Posted on 2022-11-12, 18:23
I don’t know what the difference is between a Yellow colored BAD Clusters and a RED colored BAD Cluster? Yellow vs Cyan is a progress indication, with yellow being processed and cyan is the ones to be processed. Yellow Bs are processed blocks with some bad clusters in it. The red Bs that are still …
Re: How to filter out very high frequencies with a circuit?
Posted on 2022-11-12, 17:12
You mean something like a first-order RC (or LC) low-pass filters in the speaker systems? You can play with calculators and try it out: http://www.claredot.net/en/sec-Sound/low-pass … s-over-12dB.php
Re: Getting 387sx coprocessor working.
Posted on 2022-11-11, 11:16
The JP2 is likely about selecting synchronous vs dedicated NPU clock. The board is missing NPU clock generator, but both CPU and NPU are rated for 25MHz, so JP2 is soldered to select synchronous mode. That's about all there is to switch about NPU, so it's quite likely you've damaged it.
Re: Retro Software Development?
Posted on 2022-11-08, 08:25
Somehow this example list is all about products, mostly completed or aimed to alter/adjust already existing, mixing hardware production and software announcements. It's not the retro software development talks. What if I want to develop a new game, or game engine for DOS, but looking from the …
Re: Trident tvga9000 -1 rom?
Posted on 2022-11-06, 07:52
Btw, why are you asking for -1 rom when your chip is -2 ?
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