VOGONS


First post, by Timpanogos Slim

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Bought one of these off ebay like a doofus thinking i could use it to boot a hard drive in an old industrial PC (actually the guts of an old point of sale system - ISA backplane and single-board cx486slc2-50 computer).

Very disappointing to see that the bios on it won't even try to boot an IDE hard drive. And the bios on the computer won't see the tertiary or quaternary interface.

Thought I'd join the forum to share some wisdom, since this is one of the few places I've found with google that crufty old gear like this actually gets discussed.

It's been noticed by more than one person that the FloppyMAX appears to be almost exactly an EIDEMAX card.

It sure is.

To convert it to a normal primary or secondary IDE card you'll need a soldering iron, some solder wick, some flux, and some jumper pin strip. Or just a bit of wire if you want to hard-wire the IRQ.

Apply some extra flux to your solder wick and use it to empty out the through-holes for the other three IRQ jumpers. Then solder in six more jumper pins. I used two strips of 3, you could use 3 strips of 2, or just hard-wire the irq you want. The 'fingers' are there and connected. You just need to select the irq you want.

The other difference on the EIDE-MAX is that it has R7 and R8 instead of R9 and R10.

R7 and R10 are both "0 ohm" resistors which are basically just a juper wire that a pick-n-place robot can pick and place as though it were just another resistor.

R8 and R9 are both 4.7k resistors.

So, use some more of the solder wick to suck the excess solder out of the through-holes for R8 and R7, and to desolder R9 and R10.

The install the 0-ohm (single black stripe) in the R7 position and the 4.7k in the R8 position. Peel off the stickers, set your jumpers, and go to town.

I disabled the bios because right now i don't need special bios to boot a 16-meg disk-on-module. my expectation is that it's still going to look for an LS-120 drive rather than anything else.

If you had the XT-IDE universal bios installed in the bios socket, it would probably boot without modification, and it would boot from any drive on any port too. But I don't have an eprom programmer. Unfortunately, the bios chip on this card is what's called one-time-programmable. Basically an oldschool eprom without a window that you can use to expose it to UV light to erase it. I've heard rumors that a dental x-ray can be used to erase these, but you still can't prrogram it on the card itself - you need a programming interface.

If you had a 28-pin flash device of the right sort of specifications, you Might be able to use a linux box with an RTL8139 network card to write it, using ct-flasher. I have never done this, but you can read about it here:

http://ctflasher.sourceforge.net/

Alternately, if you know someone with an XTIDE card, they can burn a prom for you on their card.

I might look into it myself if i decide i want a bigger playground than the DOM i have installed now.

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Reply 1 of 4, by kixs

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Nice guide.

I almost bought one of these mistaking it for EIDEMAX as it looks almost the same. Later I found a boxed EIDEMAX for a good price. But it still sits on a shelf as I don't have the time to test it - amongs a pile of other stuff 🙁

Requests also possible

Reply 2 of 4, by Timpanogos Slim

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I did go ahead and re-enable the bios, and as expected it just says it didn't find a UMC device (or whatever terminology they refer to an LS120 with) and states that it won't load because main bios is managing A and B.

So, without a prom with either the EIDE-MAX bios or the AT version of the XT-IDE universal bios, it's just a single-port IDE interface. Which is pretty much what i wanted, though i doubt that this mid-90's industrial PC -- which has no bios support for optical drives -- will support drives that require LBA addressing.

I guess i will have to figure out how much i expect to actually do with a highfalutin 386sx with 16 megs of ram. I had been thinking of stuffing my LAPC-1 and SCC-1 into it. I'll need to add a -5v supply for the LAPC-1 (not a huge deal if you can build circuits - just hang an LM7905 off the -12v rail) and maybe install some DOS midi software, or some very old version of Linux with some Linux midi software.

Of course, the LAPC-1 and SCC-1 don't *need a host OS at all.

Reply 3 of 4, by Timpanogos Slim

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Finally got an eprom programmer. I put an SST27SF512 with XTIDE Universal Firmware (binary of 2.0 beta 3, AT Large build) on the modified FloppyMax board and it will boot large drives from primary or secondary ide ports.

Probably any 32k flash or eprom or cmos-eeprom dip-28 chip that is pin compatible with a 27c512 will work. I'm pretty sure there are numerous options.

I used the option where you fill the whole prom with copies of the bios, not sure if that is necessary. Sometimes it is.

If you build the bios yourself you could probably boot off the tertiary or quaternary port and not modify the board, probably.

FreeDOS is fine booting from secondary here.

Reply 4 of 4, by Timpanogos Slim

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make that a 64k prom. It might not even matter. But sometimes it matters? something in the 27c512 family, these days none of them are all that expensive, but watch out for counterfeit chips that are one-time programmable.

Looks like you can use the utility that comes with XUB to configure which io ports it scans. But it's a real-mode dos program so it's not going to run in late versions of windows.