With the latest commits that add ESDI emulation (not to mention the MCA support and all of the other goodies), it looks like my original wishlist in this thread has just about been fulfilled. I never would've dared to hope it would have all happened so soon! :) Just a couple of quick questions: firs...

SarahWalker wrote:Indeed. You can pretend that 'Internal IDE controller' says 'Generic IDE controller' if it makes you feel any better.

Perhaps it actually should be changed to "Generic IDE controller" to avoid any further confusion along these lines?

Good answer, leilei. I agree with most of what you said there. PCem's good, but it's nowhere near "most accurate pc emulator" as someone has claimed many times before (and neither is DOSBox). I don't know about this--are you saying that there's no one PC emulator that stands head and shoul...

On video card support: Minix used a horrible (but effective) trick to speed up scrolling the screen. Instead of actually moving data around (copying all lines "up" one line at a time), we used the "video RAM start address" register to "move" our viewport window around,...

Agreed. These are fantastic, and much appreciated. Whenever you (or any other contributors) do add another controller, I'd say a late-80s ESDI board would be perfect, to allow for larger drives and faster/easier interfacing on machines like the Deskpro 386. But with these three MFM controllers, we'r...

Oh, awesome! This is the Xebec 1210 that came standard with the original XT, right? Hadn't realized you were working on it, thank you for this!

Oh, hah--that's what I get for not proofreading! I meant AT clones of course, not XT clones. So this board does seem to be compatible with the various non-IBM-brand AT BIOSes, then? There was some doubt about that on some other forums. A couple of people seemed to think it had some dependency on IBM...

- mal.sh: PCem v10.1 had less accurate floppy emulation that did not check for the validity of parameters (ie. if they match the currently inserted floppy) at all when formatting. Evidently PC-DOS 1.10 FORMAT.COM does not do something right when formatting the floppy, therefore getting an error in ...

One other question about the AT Fixed Disk Adapter: it doesn't seem to have any onboard ROM, does it? As such, I assume the standard AT ROM BIOS includes extensions that handle everything that an MFM card's own onboard ROM would typically handle, right? But if that's the case, how is it that the emu...

IIRC, Battler has already written up an implementation of the NS PC87306, as well as a number of other Super I/O chips. He was focusing pretty heavily on those for a while. Unless there are some unresolved issues that he knows about, it should be easy enough for him to submit them to Sarah and get t...

Whoa, that was fast! Sarah, you are awesome. Looks like a pitch-perfect implementation from what I see so far.

BTW, did you base this on the first or second-gen version?

This is an interesting observation, and should probably be looked into. All I would add is that, if the Advanced/ZP is added (which probably is worth doing), the Advanced/EV needs to be retained as well, as many of us have made extensive use of it in our configurations. I have an absolutely massive ...

Interesting. Do we have any idea why the discrepancy there is so big? The fact that PCem is getting performance comparable to your 300 MHz system at a little over half its clock speed seems pretty out of whack. That's too much of a difference to be due to the obvious culprits like the "infinite...

This could be cool, but would definitely have to be implemented as a disable-able option, so as not to interfere with PrntScrn key functionality within the emulated system itself. Although I suppose it might be possible to have PCem run a handler that captures the screenshot and then just passes the...

Seems there were two versions or "generations" of the card, both by WD. The second version was also used in the XT 286. Lots of good info here: http://minuszerodegrees.net/5170/cards/5170_cards.htm#fddda_1 . Full documentation from IBM for the first-gen version here: http://minuszerodegree...

Was just looking into that myself--yep, it was developed by Western Digital and was indeed later used as the foundation for IDE. Seems like an excellent choice.

SCSI support would be nice to have, but wouldn't really serve as a substitute for proper MFM emulation. There's a fair amount of early '80s productivity software that, for whatever reason, doesn't play well with SCSI.

Good point. Maximizing the flexibility and range of supported drives is the obvious thing to do at the outset. Presumably that means looking at controllers from the last major wave of MFM cards (1986-87 or so, IIRC), yes? Some quick research suggests that there is fairly broad agreement that the Wes...

Interesting--I hadn't realized that ST-412 and ST-506 were both totally reducible to just "generic MFM" at the controller level. One controller emulated at a time seems like a perfectly reasonable limitation, of course (assuming you mean "one controller running at any given time"...

I must say that I've been thrilled at how far PCem has come in just a couple of years. For the early-era enthusiasts like me, it's especially gratifying to have a near-perfect emulation solution for emulating almost all of the major basic PC hardware elements from throughout the 1980s. The single mo...

Very cool! Glad to see this, thanks dns2kv2. I would just point out that the PS/2 line came before the PS/1 line, and specifically the PS/2 Model 30-286 is a good couple of years older than the similar PS/1 Model 2011--indeed, the former was the basis for development of the latter. Therefore, it wou...

Agreed with leilei. That "Nuked" OPL3 emulation update really steps up the accuracy. It would be a delight to have it in PCem.

Fair enough. Mainline or not, it's something that might be fun to mess around with way down the road, but if the goal is to keep PCem-proper focused squarely on emulation, that's perfectly understandable.

Even with these improvements though, I think there is an upper limit on how much performance we can get - my rough estimation would be around 500-600 MHz on current hardware. To go beyond that would mean going down the virtualisation route; this would mean loosing the ability to control emulated CP...

Fair enough. Thanks!

I'm pretty sure flyers80 was talking about Supercard Pro format support on the host side, not the guest side. It's a floppy image format that samples disks at the flux level, similar to Kryoflux. I'm not sure exactly what's involved in adding support for those formats, but it kinda seems like way mo...

There absolutely was a 64KB configuration of the IBM PC/XT, though rare. I had one for years. There are a few sites around the web attesting to this--for example, see http://www.old-computers.com/museum/computer.asp?c=286 . I also have a few early 80s computing magazines and newsletters where people...

I've just noticed that, with some of the early models, the allowed RAM size range doesn't cover the full gamut of what was available on each model during its lifetime. The cloned XT systems are a bit tricky, but I currently own (or have owned) several of these and can attest from experience that som...

Yes! I saw it once years ago and have never been able to identify it until now. What incredible luck--thank you.

Startmenu, that game in your screenshot looks hauntingly familiar but I can't quite place it. What is it?

(Also, I agree that a 4:3 windowed mode, preferably with window resizing enabled, would be a fantastic addition to PCem.)