Re: 486 Motherboard with abysmal ISA performance

Posted on 2022-04-03, 19:06

by

by maxtherabbit

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

I've attached a dump of the BIOS if anyone is interested to see for themselves This would be an impressive early 486 board, if not for the fact its from December 1990 or later (9052 datecode on one of the jellybin chips), >1.5 years after 486 release. This makes it impressively outdated design still …

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Re: 486 Motherboard with abysmal ISA performance

Posted on 2022-04-03, 18:51

by

by maxtherabbit

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

not the clock, check how many cycles read/write strobes last, and how many cycles they repeat. Normal ISA read/write takes 4 cycles with r/w strobe lasting 1 clock cycle. For what purpose? I'm willing to examine it if it will help the cause, but since I don't have a real logic probe it will be a …

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Re: 486 Motherboard with abysmal ISA performance

Posted on 2022-04-03, 18:49

by

by maxtherabbit

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Zymos POACH chipset ? Never heard of it before. Is that the name for the intel N82230& N82231 combo? Yes, intel bought the rights from Zymos Have you tried using the old AMISETUP program to tweak hidden bios settings/timings ? No because I seriously doubt this will bear fruit. This is the 1990 pre- …

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Re: 486 Motherboard with abysmal ISA performance

Posted on 2022-04-03, 12:08

by

by maxtherabbit

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

rasz_pl wrote on 2022-04-03, 10:53: Its most likely for the ram and screwing with it will not do anything useful stick the scope on ISA bus while running VIDSPEED.EXE I've already monitored the ISA clock while flogging the system with various form of video test software. The clock does not modulate …

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Re: 486 Motherboard with abysmal ISA performance

Posted on 2022-04-03, 02:49

by

by maxtherabbit

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

I've verified the ISA bus is running at 8MHz by sticking a scope on the clock pin in the slot. I haven't really poked around the delay line chip at all yet, to see which taps are being used or where they go. Decided to make a thread first just in case someone said "no retard that delay line is for …

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486 Motherboard with abysmal ISA performance

Posted on 2022-04-02, 19:48

by

by maxtherabbit

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

I've got a pretty neat 486 board here. Built in 1991, it uses a Zymos POACH chipset (designed for 286 systems) grafted to a 486 processor and cache with the help of a bunch of PAL/GALs and discreet logic. My issue with it is that despite using an ET4000AX card which will manage >4MB/sec on a 286 …

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Re: I was offered some free "flat screen" monitors, but it was not what I had expected

Posted on 2022-04-02, 15:42

by

by maxtherabbit

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

That NEC display is phenomenal. Where are these located? I'd go pick it up myself if you don't want it

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Re: SB Awe32 Upgrade Card - Goldfinch! CT1920

Posted on 2022-04-02, 14:38

by

by maxtherabbit

in Marvin \ Sound

in Marvin \ Sound

Here are the files that CT1920 CD installs : http://www.tmeeco.eu/BitShit/PCschit/CT1920.zip There's AWEUTIL.EXE instead of normal AWEUTIL.COM, with much bigger size. I imagine it has some protected mode component to trap IO writes and whatnot. Basic inspection shows: That's true. This AWEUTIL …

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Re: AWE64 card and Dream Blaster X2 GS ?

Posted on 2022-04-01, 16:09

by

by maxtherabbit

in Marvin \ Sound

in Marvin \ Sound

AFAIK functionally all of those are the exact same

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Re: Long Files Names under DOS (Utility to bypass 8.3 format?)

Posted on 2022-03-31, 19:10

by

by maxtherabbit

in DOS

in DOS

DOSLFN

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Re: IBM AT RAM expansion

Posted on 2022-03-31, 17:57

by

by maxtherabbit

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

The vast majority of 3rd party 16-bit memory expansion boards *do* support mapping memory into the 512-640kB area

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Re: SB Awe32 Upgrade Card - Goldfinch! CT1920

Posted on 2022-03-31, 14:47

by

by maxtherabbit

in Marvin \ Sound

in Marvin \ Sound

Tiido wrote on 2022-03-31, 14:43: CT1920 has its own special version of AWEUTIL that allows MPU401 emulation without the NMI mechanism that real AWE32/64 cards use. I don't know any further details though. Big if true

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Re: Market value for popular or rare classic computer hardware

Posted on 2022-03-31, 02:38

by

by maxtherabbit

in Milliways

in Milliways

Perhaps because it has svideo and CVBS outputs?

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Re: POD83 at 100Mhz, if pass syspeed is ok?

Posted on 2022-03-30, 14:12

by

by maxtherabbit

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Anonymous Coward wrote on 2022-03-30, 14:10: No that's correct. If it's *really* unstable you won't be able to pass speedsys. But if it's just kind of unstable then it'll just crash everything else. 🤣

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Re: POD83 at 100Mhz, if pass syspeed is ok?

Posted on 2022-03-30, 13:59

by

by maxtherabbit

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

I not able to modify the integrated voltage converter, and honestly I don't want to change this piece of computer history. There is no other way right? i thought if it was really unstable it couldn't pass the speedsys test That's not true. The speedsys test is far from an exhaustive test of …

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Re: disk imaging software

Posted on 2022-03-30, 00:00

by

by maxtherabbit

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

First read is always with IMD 1.18. Saves an image of any type of disk, GCR notwithstanding

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Re: Native PS/2 mouse implementation for 386/486 boards using the keyboard controller

Posted on 2022-03-29, 16:48

by

by maxtherabbit

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

the ticket to making it as thin as possible would probably be to move the resistors, caps, and inverter to the underside and place the inductors next to the mouse header then you could make it as thin as the PCB itself (1.6mm) + the insulation height on the shortest pin headers available (~1.5mm) + …

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Re: Native PS/2 mouse implementation for 386/486 boards using the keyboard controller

Posted on 2022-03-29, 03:19

by

by maxtherabbit

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

My board was never really intended for the motherboards that place the KBC on the rear edge tbh. I tried to make it as small as possible on general principles but I don't even own a motherboard with the KBC there to design around. To be clear what I was proposing was to solder the KBC directly to …

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Re: 3 (+3 more) retro battle stations

Posted on 2022-03-29, 03:15

by

by maxtherabbit

in Marvin \ System Specs

in Marvin \ System Specs

Those are all SMD bypass caps IIRC. If anything removing one would make it less stable not more

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Re: 3 (+3 more) retro battle stations

Posted on 2022-03-29, 01:02

by

by maxtherabbit

in Marvin \ System Specs

in Marvin \ System Specs

wow

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