alvaro84 wrote on 2019-02-05, 14:37:
I have a Hedaka (PCChips) HED988 and an Octek Fox II with Headland HT12 chipset, both have EMS drivers that I downloaded right from the Vogons library. It's quite nice to see EMS in a 286, especially with 4MiB that would have been a ludicrous amount in the 286 days. GLX player can use it to play mods and s3ms that don't fit in the low 640k 😀
The Hedaka can, on the other hand, handle 16MiB - with caveats. It takes some entering and exiting to/from setup to get it working until the next reset. But then it's a 286 with its address space full of delicious RAM 😁
The D60 based boards I've tried (and the extra BIOSs I've also tried) from the 988, M205, and M209 all also seem to do EMS, XMS, and shadow RAM configuration in the BIOS, not through drivers in DOS. The drivers are needed to enable EMS in DOS and to configure RAM disks, disk cache, and/or print spool buffers. (at least that's what the PC Chips driver utility has that I got on a 5.25" disk ... haven't tried the vogons drivers, but there's a nice, apparently new old stock supply of drivers + manuals for the M209 on ebay for cheap)
I'll have to try my 988 with 16 MB at some point. I finally found some SIMM sockets at a reasonable price and they're grouped in pairs that should match the SIPP hole allignment here, too, so that could be neat.
And 4 MB isn't that crazy for boards that were new in 1990 or 1991 and upgraded a year or two later. (1992 or very early 1993 was the sweet spot there for 1MB SIMM/SIPP RAM upgrades as a major epoxy factory fire caused massive shortages and price increases for new RAM in '93; and the availability of discounted/available 256kB SIMMs and SIPPs isn't great for boards with just 4 sockets that usually couldn't use DIPPs at the same time and typically already had 640k or 1MB installed, though there's the SIMM saver/extender module approach if banks are installed with sufficient spacing or side-by side and not back to front)
But, the 988 is great as it ALSO has 2MB worth of DIPP sockets, so upgrading is much more flexible than most SIPP and SIMM based boards, and 2MB is mighty useful for games and other 16-bit software from that period, though 4 MB gets you a bit more breathing room for Windows 3.x and some demanding EMS capable games (or games that need EMS and enough base memory to require DOS loaded high in XMS ... though QRAM style real-mode UMA/EMS-enabled limulators might also work around that with no XMS)
So the 988 has the best of both worlds of the PC Chips M205 and M209, aside from being a bigger board. (I think the full baby AT board dimensions)
And from a modern-retro standpoing, the 2MB of DIPS makes it convenient when 60 ns 256kx4-bit DIPS are plentiful on ebay, at least if you want to try overclocking. (the D60 seems to do fine at 20 MHz with 80 ns RAM or better, might do 22-24 with 70, but doesn't seem to do 25+ without 60) And DIP ram of any speed tends to be more common than SIPP modules or SIMM sockets anyway.
That and a 286 20 or 25 with a low wait state VGA card, sound blaster, and CD-ROM drive might be good for a few real-mode RPG and graphic adventure games that need more than 2MB of base+EMS memory. (and some 3D games, but given it's marginal for X-Wing, I don't think Tie Fighter would fare very well ... though the poly-counts aren't much higher at minimum detail and then there's X-Wing CD that lacks the polygonal HUD and drops to flat shaded rendering at the lowest detail settings rather than the dithered gouraud shading ... I should try that actually, and having all those digital sfx avoids weird, card/module dependent general midi sound effects like the floppy disk version has)
CrossBow777 wrote on 2019-02-05, 15:24:
Yeah the memorex/telex 286 I had used a Headland chipset in it. But the actual CPU was an AMD. I know because more than once (I was stupid and young...) I could open the hatch that contained the actual die and remove it and did several times to look at it. It always still worked afterwards. Though I suspect my grimy fingers back then likely would have made that CPU die a corrosive mess today.
I think you may have had a CLCC (ceramic leadless chip carrier) packaged Am286 in there. Those tend to have clamped-on heatsinks/heatspreaders that also serve to clip the CPU in place (it just sits there sort of like modern LGA sockets; the CPU leads work like lands)
I'd initially thought some of these were just typical leaded chip carrier sockets with clipped-on heatsinks for added reliability of the hot, NMOS 286 chips, but I now think all of the ones I've seen around are the leadless ceramic type ones.
So you weren't handling a bare die and probably didn't do much damage to those gold-plated leads (mechanical scratching would probably worse than corrosive grime). The metal die cover on the underside does take up a lot of the surface real estate, though. (it's weird to handle a wafer thin ceramic package like that with no pins or bumpy leads on it)
I bet that hatch looked something like this one on a Suntac based board (which appears to have a 10 MHz AMD 286 factory overclocked to 12).
The downside for me here is I'd have to solder in a normal PLCC socket if I wanted to swap in a fast/overclockable CMOS chip, but this is super cool intact as-is. I could put a 12.5 MHz CLCC in there and try pushing it to 16 MHz or so.
And with a tiny dab of zinc oxide based thermal grease applied, I closed that back up ... and it seems to conduct quite well. (warms up fast, but seems to do its job as the aluminum fins don't top out quite as hot as NMOS PLCC 286s I've had running ... at least going by the how-close-to-burnt-is-my-finger test)
This Suntac chipset is supposed to support EMS as well. (though might not support XMS and EMS at the same time) And this board supports up to 4 MB via DIP chips (using 36 1Mx1-bit chips ... and I've got an old DEC VME system RAM board with 4MB of 70 ns CMOS DRAM I could pull and re-use here: Dad had that and was going to toss it a couple years ago, he had a whole VME rack + system unit he got surplus from work somewhere around 1992, but the rest of the system boards got recycled around 2002, around the same time as he junked his big AT tower case I think ... and maybe the B&W VGA monitor from the first computer build he did for me around '93, but that might've been later: he didn't do that without asking me first, mind you).