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XT-IDE vs. Overlay Speed

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Raven

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At one point in the past I put my XT-IDE into a 486 and was chastised for not using a 16-bit IDE controller. The reasoning behind this was twofold - first, it allowed me to add an IDE header to the existing two. Second, it supported large drives without an overlay which slows things down. However, it's 8-bit, so is slower in that regard.

What is worse, though, an overlay or an 8-bit card? I'd love to stick a huge disk into one of my 486s, but overlay software glitches with anything 80GB or above in my experience, so that isn't even an option. I've tested the XT-IDE with up to a 750GB disk and it works fine.

What some people seemed to insinuate is that I should get a 16-bit IDE controller and somehow shoehorn the XT-IDE firmware onto it - is this even possible without code rewrites?

Assuming that I were given a choice between an 8-bit XT-IDE and a 16-bit controller with a drive overlay, what would be the optimal choice for performance?

At the moment I am using a 4GB drive in one of the 486 boxes with overlay, and the overlay doesn't slow things down noticeably. If the overlay supported a huge disk properly (it should, but I doubt it was tested and seems to have issues with corruption in my testing) I'd just do that.
 
If you got something like a network card with an empty ROM socket on it, you could place the XT-IDE ROM there. Make sure it's set to 8KB, though.
 
I don't think a drive overlay causes that much of a performance hit (if any) compared to crippling the data path to 8-bit. I'd say using an overlay > than an XT-IDE card in a 16-bit ISA bus.
 
Ontrack Disk Manager was the overlay I was using before, and I am now trying out EZ-DRIVE 9.06W with a WD 80gb disk. Maybe this will work with larger disks..
 
i'm with per.
Find some card, a NIC perhaps, that has an open ROM socket on it. Burn the XTIDE 16bit version onto it and put it in the NIC. Turn off the IDE controller in your BIOS or disable the BIOS on your IDE card if it's not onboard. Then you'll have the best of both worlds. (and as the one who originally did the chastising, I am sorry- didn't mean any harm)
 
Will the NIC still function normally in that kind of scenario? How can the XT-IDE BIOS universally function with any IDE controller, especially when it's not even mounted on it? Does anyone here sell pre-burned ROMs (my ROM burner is arse..)? Finally, this should also just as easily work on a PCI card, right? Not that I'd need it to, but should it work on PCIe (curious)?

If someone has ROM burning capabilities and spare chips of the type that go into BOOT ROM sockets on NICs, I'd gladly trade for some, and purchase at least one, perhaps two, if trade isn't an option.
 
Raven said:
Will the NIC still function normally in that kind of scenario? How can the XT-IDE BIOS universally function with any IDE controller, especially when it's not even mounted on it? Does anyone here sell pre-burned ROMs (my ROM burner is arse..)? Finally, this should also just as easily work on a PCI card, right? Not that I'd need it to, but should it work on PCIe (curious)?

If someone has ROM burning capabilities and spare chips of the type that go into BOOT ROM sockets on NICs, I'd gladly trade for some, and purchase at least one, perhaps two, if trade isn't an option.
Click to expand...

The thing is that the ROM sockets on the NICs are designed to fit a BIOS extension. Now, the extension you would want on a NIC is usually a routine that remotely boots the machine from a network, but since this is of no use for most people, that ROM is not presented on most cards.

The ROM socket and it's support logic has nothing to do with the NIC itself. It just maps the contnents of the ROM inserted somewhere in high-memory where BIOS Extensions are expected to be found. Becuase of this, any extension ROM of the right size and type (usually 27xxx) can be plugged in without any future ajustements.

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I don't know if the XT-IDE BIOS works with standard AT controllers or not, but I do expect the AT-version to work at least. Ask member aitotat for details on this. As I said above, BIOS extensions are independent of what card they are mounted on. As long as they appear in memory at the rigth place without overlaping; it'll work.

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Any PCI/PCIe card with a BOOT ROM socket should work I guess, else it wouldn't be called "boot rom".
 
...and you already have the eeprom burner you need: the XTIDE itself!
Go to mouser.com or jameco.com and buy a 28c64 (with jameco you will need to call them to make sure you get the atmel, not the SEEQ part).
Pop that blank eeprom into your XTIDE card.
Flash xtide_at.bin in.
Remove the eeprom and plug it into the NIC card. There is typically some bit of software (for 3com cards anyway) to let you configure the NIC itself and describe what type of ROM you've plugged into it before it will enable the rom option.
You must disable the BIOS for the onboard IDE controller, either in setup or if it's on its own card, there hopefully is a jumper. We do this because we don't want 2 sets of software talking to the same hardware.

This is one of the coolest tricks you can do in any 286+ machine with an onboard IDE controller with lame 528MB limiting onboard BIOS.

Note:
the XTIDE BIOS (the one that works on our card) will *not* work on a 16 bit IDE controller that you'll find in a 286 or higher machine. If you do this, you *must* use the AT version of the XTIDE BIOS (available in the same zip off the xtide wiki)
 
Brilliant - my favorite machines, my Presario 425 and it's friends, are all limited to ~500MB disks without overlay software. It has to ISA slots, but I like to use those for network and sound, since those are two things that they don't have onboard (except the NET1, it has onboard net).

It's nice that the XT-IDE can do that - can it burn anything to compatible chips (I'd imagine so)?

I will indeed do this. ;D

Edit: Excuse my noobness with these things, but there appears to be a few varieties of 28c64 besides just the manufacturer - on Jameco, for example, "SOIC-8" and "DIP-8". I know what DIP is, but am unfamiliar with SOIC. Does this matter? SOIC is cheaper for some reason. On eBay there are a bunch of explicitly Atmel-branded 28c64 chips, but they seem to be a ripoff, tell me if I'm wrong..

http://shop.ebay.com/i.html?_nkw=at...at28c64&_osacat=0&_trksid=p3286.c0.m270.l1313
 
Raven said:
Edit: Excuse my noobness with these things, but there appears to be a few varieties of 28c64 besides just the manufacturer - on Jameco, for example, "SOIC-8" and "DIP-8". I know what DIP is, but am unfamiliar with SOIC. Does this matter? SOIC is cheaper for some reason. On eBay there are a bunch of explicitly Atmel-branded 28c64 chips, but they seem to be a ripoff, tell me if I'm wrong..
Click to expand...

Gotta have DIP. SOIC is a different package type and for surface mount boards.
SOIC is cheaper because they are still modern and in production. I think pretty much all DIP devices aren't being manufacturered anymore.

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I've also been threatening to do this for awhile now, but I've already upgraded one of my machines with this IDE controller NIC card trick, so there is no reason for me not to be writing up an entire tutorial on how to do it and what software to use. I had to dig for awhile to locate the setup utility for the 3com card I used, so I might as well make that easier for others... I'll *try* and get some of that together tonight.
 
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