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if you put a 16 bit ISA IDE card in a 5150

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neutrino78x

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Ok, so, if you had a 16 bit ISA card for IDE, which had its own BIOS to get around the 512 MB limit) and you put this in a 5150, would you then be able to access a modern IDE hard drive? Is there any way to tell externally if a given 16 bit ISA card will work in an 8 bit slot?
 
neutrino78x said:
Ok, so, if you had a 16 bit ISA card for IDE, which had its own BIOS to get around the 512 MB limit) and you put this in a 5150, would you then be able to access a modern IDE hard drive?
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Nope. 16-bit IDE controllers use IRQ 15, which doesn't exist on XTs. The IDE registers at 1F0h-1F7h will be accessible, but the controller is pretty useless without an IRQ.

neutrino78x said:
Is there any way to tell externally if a given 16 bit ISA card will work in an 8 bit slot?
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If the card has extended memory or uses IRQs above 7, it won't work.

VGA cards (for example) nearly always work in an 8-bit slot because they don't use any of the ISA bus's extended features except for the MEMCS16 line.
 
Fallo said:
Nope. 16-bit IDE controllers use IRQ 15, which doesn't exist on XTs. The IDE registers at 1F0h-1F7h will be accessible, but the controller is pretty useless without an IRQ.



If the card has extended memory or uses IRQs above 7, it won't work.

VGA cards (for example) nearly always work in an 8-bit slot because they don't use any of the ISA bus's extended features except for the MEMCS16 line.
Click to expand...

With a soldering iron, the IRQ problem will not be a problem, but getting software to use a low IRQ may not be so easy. However, the IDE interface is 16-bit and the bus is 8-bit. The IDE connector is almost directly wired to the data lines on the bus. I think that you may have a problem there where the drive is expecting 16-bits and only receives 8-bits.
 
One trick used by some of the vintage folks is to use only half of each disk sector. This is pretty good if you've got an old system that's expecting (or can handle) 256-byte sectors, but even so, you can write a driver that will combine two half-sectors to get a full one (or even modify the card's onboard BIOS to do it).
 
hargle said:
You'd be much better off with our own 8bit IDE controller, as designed and created by your fellow vintage-computer geeks.
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Certainly easier than tracking down elusive 8-bit IDE controllers like the ADP50 and Acculogic. It's nicer too using IDE drives rather than the slow, unreliable MFM/RLL ones.
 
Terry Yager said:
"WHOO-HOOOOOOOOOO!!!YIPPIE!YIPPIEEE!!YIPPIEEEEEEE!!! Hot damn, who shot Sam!?!?!?!????"
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This, and your 'Cool Hand Luke' flavored post of a couple of hours ago !

You're meant to be taking 5 of the green pills and 2 of the yellow pills.
You got the colours mixed up again, didn't you?
I know. I do it myself.
 
hey, how much would one cost? even though i don't have a 5150 or XT or anything like that, it would be nice to have one
 
linuxlove said:
hey, how much would one cost? even though i don't have a 5150 or XT or anything like that, it would be nice to have one
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I'll try not to cross thread too many times about this (there are 2 other threads with these questions in them) but it's being sold at or just slightly above cost.
At the moment, cost is roughly $45, but will go down the more we bulk order parts and PCBs. I'm trying to get it under $30, but I'm not sure if I can. It'll be available in a kit form that you solder, and as an assembled and tested version.
I'll know a lot more about costs in a month or two after the first batch of 10 PCBs are built and tested.
 
Great Hierophant said:
With a soldering iron, the IRQ problem will not be a problem, but getting software to use a low IRQ may not be so easy. However, the IDE interface is 16-bit and the bus is 8-bit. The IDE connector is almost directly wired to the data lines on the bus. I think that you may have a problem there where the drive is expecting 16-bits and only receives 8-bits.
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Adding insult to injury, at least one of those BIOSes must make use of REP INSW, which wouldn't work on 808x machines.
 
That begs an interesting question.

On my model 25, how does the printer port HD enclosure work? If the input is 4-bits nibble mode only, then how does that work? Some form of proprietary encoder?
 
the model 25/30 doesn't use a stock IDE interface. Those HD's had to be specially manufactured for it.

Why not supply the artwork and eprom images so we can make our own xt-ide card/s from scratch. I sat in on a talk at a computer festival over the weekend and have learned how (given proper artwork) to make pcb's for so little money (and equipment, you do need a laser printer or copier though (or you can run to Staples/Office Max/etc.) it's ridiculous. And it's said to be a pretty foolproof method. I'll probably try it myself in another week or two.
In the interim stock up on Knox flava-less gelatin. Once this gets out, it will literally fly off the shelves. Actually (1) 1.69$ box is enough material for 50 boards!
Oh, you will need a drill thingee to make the holes in your pcb's also. I found me a cordless Dremel for 20 bucks at Target last week. I must say I do love clearance specials!
 
tipc said:
Why not supply the artwork and eprom images so we can make our own xt-ide card/s from scratch.
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Everything you need will be available starting here:
http://wiki.vintage-computer.com/index.php/XTIDE_project

The hardware designer has his own workplace set up here:
http://n8vem-sbc.pbworks.com/browse/#view=ViewFolder&param=XT-IDE

The final products from the n8vem page will be linked to from the 1st link.

We're still hammering out the design and code, so those aren't quite ready for public consumption yet, but when a release is made, feel free to take whatever parts of it you want and make your own designs out of it.

The entire body of work will be covered under the GPL.
http://en.wikipedia.org/wiki/GNU_General_Public_License

I don't know if that can cover the artwork or hardware end of things, but I ask that you not sell-for-profit your home brewed PCBs in competition with the ones we're having professionally manufactured. You'd then effectively be stealing our work for your own gain, and the wrath of VCF will be upon you. :)
 
Any of the parallel port devices that work on a standard parallel port (SPP) use nibble model to read from the device. So they can only read 4 bits at a time, but they can write a full byte at a time.

The software drivers know this and adjust accordingly. You will see read speeds that are about 1/2 of write speeds.

What is interesting is how it is done. Data goes out on 8 data lines, but data coming in actually comes in on control and status lines, not the data lines. In an SPP the outgoing data lines can not read data - period. (Well, in some implementations you can, but you also risk cooking the chips that implement the port so we will leave it as I said it.) The only way to read data from the device is to use the extra control and status lines, of which there are 5.


Mike
 
hargle said:
The entire body of work will be covered under the GPL.
http://en.wikipedia.org/wiki/GNU_General_Public_License

I don't know if that can cover the artwork or hardware end of things, but I ask that you not sell-for-profit your home brewed PCBs in competition with the ones we're having professionally manufactured. You'd then effectively be stealing our work for your own gain, and the wrath of VCF will be upon you. :)
Click to expand...

hey hargle, if the intellectual property is released under the GPL, I do not believe you can sue someone for using it to make a product they sell for a profit. GPL allows the IP to be used for any purpose as long as the source code is included, in this case you would have to include the diagrams etc. with the board. If the person selling the product modified the design, I think they would have to release the new design of the board under GPL also, but GPL allows you to sell something based on the original GPL intellectual property.

It's just like Linux, man. The kernel is released under GPL, and Red Hat Software is legally allowed to sell a commercial distribution, as long as they include the source code. There is a Red Hat Enterprise Linux (RHEL) Desktop you can buy, for $80/year (you're buying CDs with the distribution as well as one year of tech support). Most consumers probably use the freely distributed Red Hat Fedora, though; RHEL Desktop is intended for business.

If you want to restrict the use of the IP in a different way, you would have to hire a lawyer or something and write a different license...

--Brian
 
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