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Another recycle-center rescue...

I came home with about 60 some odd jewel cases of old software for dos and windows 95 or 3.1 I've never heard of before all for $1.50, and about 6 boxes of DD 360kb 5.25" floppies, brand new sealed in the box, all 6 boxes for another $1.50 ... anyway, want me to get that one for you too?
 
kithylin said:
I came home with about 60 some odd jewel cases of old software for dos and windows 95 or 3.1 I've never heard of before all for $1.50, and about 6 boxes of DD 360kb 5.25" floppies, brand new sealed in the box, all 6 boxes for another $1.50 ... anyway, want me to get that one for you too?
Click to expand...
That'd be lovely, thanks :)

Back on the general thread topic, I'm thinking of ways to tweak the performance of this system a bit; the obvious step would be to replace the CPU with a 40MHz 386 (the board does support this,) but that's something I'll have to bide my time on until I can find one priced inexpensively. Maxing out the cache would be another improvement, I'll have to check and see what type of RAM chips are used. The other improvement I can think to try is to replace the main memory; I believe the SIMMs currently installed are 80ns, and I know I can get 70ns and even 60ns 30-pin SIMMs. I'm just wondering how likely that is to work; I assume the chipset imposes a limit on the memory access speed (the motherboard manual says "at least 80ns FPM" but doesn't specify a lower limit to access time,) and there's also the question of what the processor itself can handle. Does anybody have any idea what the likely limit to memory speed would be?
 
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I'll work on your file in a little bit, in regards to your cache, if it will take 28-pin DIP style cache chips, there's this that I was alerted to in another thread: http://www.mouser.com/Search/Produc...rtualkey63930000virtualkey727-CY7C199CN-15PXC

9 of these would be 256kb of 15ns cache.. which I think is the fastest you can get in DIP-28, and a set of 9 would be $19.91 shipped if you chose the USPS option under shipping (I looked at it earlier). I don't know about your memory though, I have a set of 4mb 30-pin SIMMS in my ebay auction section if you wanted those, no idea what ns speed they are though.

EDIT: Your second file is here: http://www.outfoxed.net/misc/Vg2000.zip
 
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Thanks, I'll give that a try.

The cache, tag socket excepted, is populated with Motorola MCM6206CP-20ns SRAMs (datasheet here.) Looks like similar characteristics, but the datasheet has the address lines numbered in a drastically different fashion :/ Then again, since it's a simple SRAM with no fast-page mode or anything, I'd expect that shouldn't matter...

The SIMMs are 80ns as I suspected. The motherboard's apparently an OPTi -386WB chipset; buried in that datasheet, it says that "DRAM at minimum wait state" is 80ns, so I assume that means that faster SIMMs won't make a difference?
 
Well, five of those chips filled out the cache just fine, so it's now maxed out at 256KB and should work reliably at 40MHz once I get ahold of the appropriate CPU. Here's the benchmarks from Trixter's TopBench:

Code: 
[UID8876132A52]
MemoryTest=272
OpcodeTest=68
VidramTest=462
MemEATest=61
3DGameTest=57
Score=60
BIOSinfo=R(C)1985-1991,American Megatrends Inc.,All Rights Reserved.,1346 Oakbrook Dr.,#120,GA-30093,USA.(404)-263-8181. (07/07/91, rev. 0)
MachineModel=01FC
BIOSdate=19910707
BIOSCRC16=8876
VideoSystem=VGA
Machine=AT clone
Description=128Cache

[UID887613D4D1]
MemoryTest=272
OpcodeTest=69
VidramTest=451
MemEATest=58
3DGameTest=56
Score=60
BIOSinfo=R(C)1985-1991,American Megatrends Inc.,All Rights Reserved.,1346 Oakbrook Dr.,#120,GA-30093,USA.(404)-263-8181. (07/07/91, rev. 0)
MachineModel=01FC
BIOSdate=19910707
BIOSCRC16=8876
VideoSystem=VGA
Machine=AT clone
Description=256Cache

[UID88761423E9]
MemoryTest=271
OpcodeTest=69
VidramTest=452
MemEATest=60
3DGameTest=56
Score=60
BIOSinfo=R(C)1985-1991,American Megatrends Inc.,All Rights Reserved.,1346 Oakbrook Dr.,#120,GA-30093,USA.(404)-263-8181. (07/07/91, rev. 0)
MachineModel=01FC
BIOSdate=19910707
BIOSCRC16=8876
VideoSystem=VGA
Machine=AT clone
Description=60nsRAM
(By the way, it crashes when attempting to determine the CPU speed on this computer; skipping the aggressive tests avoids the issue, at least.)

As you might notice, my 4MB SIMMs turned out to be 60ns after all, so I gave them a try; it didn't make enough of a difference on the memory test to be outside the margin of error, so I'm pretty certain the board doesn't support higher speeds. I put the 1MB SIMMs back, since there was no performance boost and it took too long for the memory test to count through even 16MB, let alone 32MB.

Surprisingly, the cache doesn't make that big of a difference in TopBench, either; I don't know if that's just because even 128KB is probably sufficient to cache the whole program, or what. It does make a very noticeable difference in practical applications, though; DOOM now runs at a playable framerate in half-width mode, and Descent still isn't quite playable, but even up to half detail it's actual motion and not a slideshow. I'm hopeful that a 40MHz CPU should improve things yet further.

(Does Descent use the FPU? This computer didn't come with one.)
 
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Descent is -very- cpu dependant, I'm not sure if it's just the FPU or what, but I tried it on some other computers I have and highest detail settings were slow (but playable) like 20-24 FPS on a Pentium-75, it was better.. felt like 40's - 45's on a P-90, and it felt like mid-50's on a P-100.
 
Did a little further tweaking - this board has a configurable ISA-bus clock. It defaults to "AT clock / 10" but can go all the way up to "AT clock / 6." I played around with this a bit and got more benchmarks; AT/8 doesn't seem all that different, but AT/6 makes a noticeable difference in video memory access:
Code: 
[UID88761760D9]
MemoryTest=268
OpcodeTest=67
VidramTest=453
MemEATest=59
3DGameTest=56
Score=60
BIOSinfo=R(C)1985-1991,American Megatrends Inc.,All Rights Reserved.,1346 Oakbrook Dr.,#120,GA-30093,USA.(404)-263-8181. (07/07/91, rev. 0)
MachineModel=01FC
BIOSdate=19910707
BIOSCRC16=8876
VideoSystem=VGA
Machine=AT clone
Description=ISA=AT/8

[UID8876177131]
MemoryTest=267
OpcodeTest=67
VidramTest=421
MemEATest=58
3DGameTest=56
Score=62
BIOSinfo=R(C)1985-1991,American Megatrends Inc.,All Rights Reserved.,1346 Oakbrook Dr.,#120,GA-30093,USA.(404)-263-8181. (07/07/91, rev. 0)
MachineModel=01FC
BIOSdate=19910707
BIOSCRC16=8876
VideoSystem=VGA
Machine=AT clone
Description=ISA=AT/6
Unfortunately AT/6 seems to be causing some quirks on boot with the multi-I/O card (which is a shame, it gets along great with everything else.) Oh well.

Also, for the fun of it, I did one with the cache disabled:
Code: 
[UID88761759DA]
MemoryTest=338
OpcodeTest=155
VidramTest=458
MemEATest=195
3DGameTest=124
Score=39
BIOSinfo=R(C)1985-1991,American Megatrends Inc.,All Rights Reserved.,1346 Oakbrook Dr.,#120,GA-30093,USA.(404)-263-8181. (07/07/91, rev. 0)
MachineModel=01FC
BIOSdate=19910707
BIOSCRC16=8876
VideoSystem=VGA
Machine=AT clone
Description=NoCache
Yikes.
 
Oy. Things have been going great on the DOS/WFW 3.11 front - got everything all set up and networking configured with surprisingly little trouble (DHCP even works out of the gate once you install TCP/IP support, I was pretty flabbergasted by that.) Unfortunately, I'm having a hell of a time with alternative operating systems.

NT 3.5 will boot the installer right up to the point where it displays an NT kernel boot message, then it blacks out and doesn't come back (looks from the videos I've seen like the blackout is normal, but it's supposed to pop right back up into setup proper.) It doesn't kill the video card because my monitor would complain about "no signal," it just sits at a black screen indefinitely, and it shouldn't be a bad video driver because it's switching from one text-mode screen to another text-mode screen...

OS/2 Warp 3's installer will boot enough to display the splash screen, then comes up with an "OS/2 is unable to operate your hard disk or floppy diskette" error message. I've seen some suggestions for dealing with that such as disabling IBM's different device drivers in CONFIG.SYS, disabling the cache, and trying it with Turbo off, all of which I've tried with no success. I don't know if it doesn't get along with the XT-IDE BIOS, or what...ugh...

Does anybody have any advice to offer with either of these? I've got a spare 2GB that I'd like to use for a proper 32-bit OS, but I don't want to waste hours guessing in the dark...
 
It's got 8MB at the moment, but I'm thinking I will kick it up to 20MB or 32MB after all; some applications in Windows seem to do a lot of swapping, and once I get the 40MHz part installed the memory-check at boot shouldn't be quite so aggravatingly long. (I hope.) I'm really pretty disillusioned with Linux, though...too much pain for not enough gain, and in the end you're left with another generic Unix system. NT and OS/2 are, I think, more the kind of obscure-but-useable niche software I'd be interested in devoting a spare partition to.
 
On some of my machines hitting the "ESC" key stops the memory count. There may also be a setting in the bios to disable it.
 
Well, the 40MHz Am386 arrived today. Unfortunately, some of the pins are bent, though the Styrofoam backing isn't crushed so I don't think it happened in transit. (Though I will have to have a word with the seller - for $9.00 shipping I damn well expect something more than a stuffed plastic bag, and I don't care if it did come from Ukraine.) Luckily, they're not bent beyond my ability to straighten and they don't seem too stressed, so I should be able to get it up and running...
 
good luck with that.. bent pins is annoying. The problem of buying vintage processors any more today is most people think "this is old tech and completely useless, I don't care how I package it." I've bought other 486 processors online that have arrived with bent pins too from people that just don't care. If the cost of return shipping is not worth vs what I paid for it then usually I just try and fix it myself and deal with it... sometimes it's not worth it to bitch moan and try to get it returned and refunded if it's a < $10 item.
 
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