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Re: 286 dead, long live the 286! Sourcing and building a fast 286 replacement

Posted on 2021-01-18, 17:32

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Yeah, I think I have my heart set on a VLSI SCAMP based board now. I'm not sure anything else will do! I can see that the 82C311L has UMB (up to 384KB of it!) via The Last Byte memory manager. Does it also support emulation of EMS memory, as per the Headland chipset? The chipset datasheet certainly …

Re: VESA mode programming from real mode

Posted on 2021-01-18, 17:12

in Marvin \ Software

in Marvin \ Software

I'm using a double buffer, so I have a 256KB buffer in memory, write all of the updates to that, then flush it to VRAM in one operation (which will be in 64KB chunks compared to the X68000 and PC-98). There's no direct setting of pixels, and since there is no animation involved (only a scrollbar …

Re: PCI storage card not showing its BIOS

Posted on 2021-01-18, 16:10

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Sometimes PCI SATA cards appear as SCSI devices - does your BIOS have an option to enable booting from SCSI, or to enable/disable SCSI ROM BIOS extensions?

Re: 286 dead, long live the 286! Sourcing and building a fast 286 replacement

Posted on 2021-01-18, 15:41

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

I must admit, it does look very nicely specified indeed. One thing I'm not clear on is whether the later VLSI 82C311L is faster than the earlier multi-chip VLSI chipsets? pshipkov mentioned the VLSI 82C201 as being fastest, but I would have naively assumed that the much later one-chip 311L would …

Re: 286 dead, long live the 286! Sourcing and building a fast 286 replacement

Posted on 2021-01-18, 11:50

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

I have decided I must have a Biostar MB-1220VE . http://www.win3x.org/uh19/motherboard/show/1132 - 6+2 slots - VLSI VL83C311L 286/386SX chipset - 16MB RAM - 16/20/25MHz options as standard - Huge BIOS tuning options (according to https://foorum.hinnavaatlus.ee/viewtopic.php?p=10560390) I must have …

Re: any tips on desoldering the dallas DS12887A from a AOpen AP53

Posted on 2021-01-18, 08:16

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

If you're serious about retro computing/gaming or electronics you really should invest in a desoldering station for through-hole removal work - it does away completely with the mess of desolder braid. Probably one of the best purchases I've made in years (well, technically it was a christmas gift …

Re: 286 dead, long live the 286! Peaktron PA286-SMT / Micro Systems PA286-SA1

Posted on 2021-01-18, 07:04

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

I remember testing a sibling of your peaktron replacement board. It was pretty bad. Not surprised you had problems with it too. The ht12a one is above average, but that's about it. If you want your "speed demon", try to obtain HT12P, or especially VLSI 201 based boards. https://www.petershipkov.com …

Re: 286 dead, long live the 286! Peaktron PA286-SMT / Micro Systems PA286-SA1

Posted on 2021-01-17, 23:13

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Got a Headland HT12 board on the way. The same seller who I got the PA286-SA1 board from had a HT12HS board from 'Eurosoft' in stock, so I made an offer (based on the fact I already bought a board from him) and he accepted. Total Hardware 99 has it listed as a "Unknown G2-12HS HT12" and Deksor's …

Re: 286 dead, long live the 286! Peaktron PA286-SMT / Micro Systems PA286-SA1

Posted on 2021-01-17, 19:22

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Hey have you heard of our project UH19 ? http://www.win3x.org/uh19/ It's TH99's that we turned into a database that you can browse and that's also editable :) You can definitely help us document your board properly if you want. I think we could use the Peaktron board that's very similar to yours as …

Re: 286 dead, long live the 286! Peaktron PA286-SMT / Micro Systems PA286-SA1

Posted on 2021-01-17, 16:24

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

HT12 is a good chipset, so is VLSI Scamp. Try to find a different board that uses one of those I know about the HT12, mine served me well since around 1991/92! I've seen this one, it's a HT12 variant. Lots of ISA slots (but still baby AT), no signs of battery damage, at least 3 oscillator pads, …

Re: 286 dead, long live the 286! Peaktron PA286-SMT / Micro Systems PA286-SA1

Posted on 2021-01-17, 15:21

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Also, CheckIt 3 reports failures on the extended memory test:

Re: 286 dead, long live the 286! Peaktron PA286-SMT / Micro Systems PA286-SA1

Posted on 2021-01-17, 15:12

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Compared to the HT12 board it's horrendously slow, even at the same 16MHz clock speed. The fact that it isn't reliable at all at 16MHz with 0-wait enabled and fast 60ns RAM is pretty poor. The CPU/FPU benchmarks don't get much of a hit at 1-wait of course, because they're largely not RAM or Disk …

Re: 286 dead, long live the 286! Peaktron PA286-SMT / Micro Systems PA286-SA1

Posted on 2021-01-17, 12:31

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

So I think that the source of the crashes may actually be coming from having a combination of 0-wait state enabled and system + video BIOS shadowing turned on. I'm trying various things that were locking up the system previously and without shadowing enabled they seem to be working okay. The DOS …

Re: 286 dead, long live the 286! Peaktron PA286-SMT / Micro Systems PA286-SA1

Posted on 2021-01-17, 10:13

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

ARGH!!!! Same damn thing. With 0-wait state when doing long directory listings (such as the DOS directory, or something like Norton Utilities 😎 you get random hard lockups. Switch back to 1-wait state and they complete every time; the only pause being the free-size calculation for the drive (slow as …

Re: 286 dead, long live the 286! Peaktron PA286-SMT / Micro Systems PA286-SA1

Posted on 2021-01-17, 10:00

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

As expected, the performance of the system with 1-wait is dog slow. Norton SI drops from 12.1 to 9.3, Landmark CPU drops from a synthetic 24.6MHz to 18MHz, and so-on and so-on. Approximately 25% slower across the board, and disk IO is a pathetic 900KB/sec. Compared to my old rock-solid HT12 board, …

Re: 286 dead, long live the 286! Peaktron PA286-SMT / Micro Systems PA286-SA1

Posted on 2021-01-17, 09:33

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

On further testing I'm finding that this system has unreliable IO (both floppy and CF/hard drive) with the 0-wait setting left enabled. Just trying to get DOS 5 installed with 0-wait enabled results in random freezes and hangs whilst copying floppy contents to the hard drive / CF card during setup. …

Re: 286 dead, long live the 286! Peaktron PA286-SMT / Micro Systems PA286-SA1

Posted on 2021-01-16, 18:16

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Damn. Went to fit the Harris chip and the 40MHz crystal I was going to use has had a leg snapped off whilst in the box of other oscillators. It works perfectly on the 32MHz crystal, as you would expect (with identical benchmarks results since there is no architectural difference between AMD and …

Re: 286 dead, long live the 286! Peaktron PA286-SMT / Micro Systems PA286-SA1

Posted on 2021-01-16, 16:58

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

First round of benchmarks completed. This is at the standard 16MHz cpu speed with 0-wait enabled, no parity and shadowed video and system BIOS. - AMD N80L286-16S at stock 16MHz speed via 32MHz clock - Intel i287XL - 0 wait state enabled - system and video BIOS shadowed - 2x 60ns 4MB SIMM modules - …

Re: 286 dead, long live the 286! Peaktron PA286-SMT / Micro Systems PA286-SA1

Posted on 2021-01-16, 09:26

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Found a memory configuration larger than 4MB which works! The main jumper SW1 block needs the following jumpers set: SW1 J5 closed SW1 J6 closed SW1 J7 open SW1 J8 open According to the silkscreen on the board that configures one bank (J7/J8) for 4MB (J5/J6) memory module sizes. This results in 8MB …

Re: 286 dead, long live the 286! Peaktron PA286-SMT / Micro Systems PA286-SA1

Posted on 2021-01-16, 09:07

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Next steps on this is to fit a DIP socket for the oscillator so that I can run tests with various speeds (looking in my parts box I have 32, 38, 40 and 50MHz oscillators) and several processor brands and speeds (two AMD-16 with different date codes, a Harris-20 and a Harris-25). I expect, based on …

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