ijor

I think he meant that when you use a Gotek and then manage the Pen Drive on a PC, you don't see the files directly, you see disk images. So he probably finds a little annoying the need to deal with disk images. But as I just replied, newer versions of the firmware can take a directory on the Pen Drive and convert them to a virtual disk on the fly. So actually you don't necessarily need disk images anymore, at least not for many cases.

This is not accurate anymore. Later versions of HxC firmware for the Gotek does allow you to use actual files directly, without need to embedding them in a disk image.

I doubt many would agree that a track buffer is not important, to say the least. The track buffer was the most important feature of the Happy. The much faster loading time thanks to the track buffer was probably the main reason that people bought the Happy in the first place. The track buffer has several other benefits, including the possibility of uploading a completely new OS. The Happy could "emulate" The Chip/Archiver for that reason. But all of these were hacker tools that many people didn't care too much. Use a sector copier with a Happy (or other similar enhancements like the Speedy), and you can never go back to a drive without track buffer.

Interesting information indeed about the stepper. I'm not sure, but I still believe the WST mechanism should be "backwards" compatible. Otherwise all the 1050 enhancements would not work reliably and the issue would have been known. If it is the other way around, if the WST ROM can be used reliably on a Tandon mechanism, this is less certain. Anybody knows more or less when the first WST mechanism were brought to the market?

Unfortunately he does not, and he doesn't accept interviews either, I understand. The same as Mike Gustafson (Sparta & ICD), the same as Richard Adams (Happy) ...

Bob Puff (CSS) is extremely talented and he designed great products. Although, IMHO, they were sometimes a bit "cheap", hackish designs, especially when you consider the prices. That solution was very clever, typical of Bob, but there are more elegant and simple solutions that would allow you to control the FDC pin 31 NAND without affecting the bank switching. One possibility is to use a mux decoder to get 4 separate control signals from two RIOT outputs. This might have increased the cost, but by how much? The BitWriter requires the Archiver and the total price was something like U$150. Doesn't look like an extra small gate would be very significant for such a product. Could probably include a full 6502 as well.

If this is an original demo and not just a copy of the original disk, then it is extremely rare. I never heard about a demo of MULE. Can you post a picture of the disk please.

No. The author was using an Intel 8271 FDC in this case, which belong to the PC FDC family. Later BBC micro changed the FDC and used the WD1770. So you have BBC models with different FDC chips. But the WD1770 is very different than the FD1771, just the number is almost the same. The FD177X is the earliest FDC generation by WD and was used in the 810. The WD177X is the latest generation and was used on the XF-551. Only the FD177X supports that odd sector size scheme. Not at all. There is no relation, historically, between the different terms and the different variations. There wasn't any formal terminology. There were no formal bibliography and most of the information on the subject was pretty much secretive. Each one came up with his own terms. Even with double sectors you have the same things. What is the difference between double or dup sectors, even called Phantom in some cases? No difference, just different terms assigned by different people and companies. Back at the day I never heard the term flaky. I used the term weak because that's the first one I heard, I believe from Happy computers. Later I also heard the term Fuzzy, used by CSS of course (Fuzzy sector maker), also used at the Advanced Copy Protection book. Btw, checking the book now, I see it also uses the term "unstable" and "phantom". So you can see, there are even more terms. May be there were even more used in other platforms.

Actually the FD1771 supports a maximum sector size of 4K. But there is no need to restore to that trick. The WD FDC format command works in a very different way than the PC FDC. You can easily format a track without sectors if you want. Obviously copiers like the Happy must create blank tracks and it's not a problem at all. No. The article is wrong. You can't create reliably weak bits with such a method. It might work in some cases, but even then if won't be very reliable and might produce weak bits when read in some drives, but not when read on others. IMHO the article is not very accurate at all. His distinction about the different meaning for the flaky/fuzzy/weak terms is his own pure interpretation/speculation. The BitWriter is not designed to create weak bits. For this purpose the SuperArchiver has the fuzzy sector maker that is a very simple piece of hardware.

I agree with bfollowell. The USB HxC emulator is almost obsolete and useful mainly for special purposes only. HxC also makes a SD emulator that is much more popular than the older USB one. It is more expensive than the Gotek (can't compete with chinese manufacturers), most would agree it's higher quality than the Gotek, but for most purposes, not as powerfull.

(Re: WST ROM on a Tandon mechanism) Interesting, good to know. I doubt ED would make much of a difference, although of course, we need more exhaustive testing to be sure it works reliably. But the main issue that might be difficult to test is that it might depend on the specific stepper. It seems reasonable that perhaps earlier drives with older stepper would not work, and newer ones wouldn't have a problem. A Tandon ROM patched for faster stepping would be identical to a WST ROM. Below is a link to thread about all the 1050 ROM revisions.

Check Amazon Uk.

After Jeff used the patched USD ROM, I think we know now that the faster step rates do work in a Tandon mech. At least in some of them, probably in all later ones. Phase encoding should be the same, otherwise 1050 enhancements (USD, Happy) wouldn't work on WST mechs. What might be incompatible, is the extra step that the Tandon ROM performs and the WST doesn't. Somebody should try a stock WST ROM on a Tandon mech and we will know.

As advised, get a Gotek floppy emulator. They are very cheap and widely available.

Great work, as usual. Didn't have much time to look into the SCP image. But I'll wait until getting a dump from "gnusto".

Most Atari disks, even those recorded using industrial duplicators are not aligned to the index hole. But for multiple reasons we still want the index skew alignment recorded in the image. Ah, ok. I might be mixing the SCP modes. As long as it stores the index position, if present, then it is fine. The older the drive the more likely it can read disks without the index. Newer DD ones it depends many times on the jumper settings. Don't know about the Toshiba ones, but the TEAC ones probably should work. The TEAC drives usually have jumpers to set the "READY" or INDEX condition. Yes, that's exactly the problem with newer drives. They don't become ready at all if they can't sense the index hole.

This is not very recommended. You can't help it for the back. But the front side it's better to dump using the index hole. It is more accurate and we don't loose the skew information that might be valuable. A different dump on a different drive might be useful. But if all those tracks are heavily damaged, probably it won't be much better. Anyway, on cases like this it might still be worth to try.

Do we have a SCP dump of Zarxx's disk, or only ATX? Most DD 40 tracks drives can read disks without the index hole. A good example is the original Mitsumi mechanism on the XF551 that can access flippies. But the software has to support dumping without index hole. The SCP does but the Kryoflux doesn't, or at least it didn't the last time I checked. That's an important plus for the SCP, although on the other hand, the Kryoflux can read both sides in one pass on a modified drive.

Touch screen controller technical info: Anybody has any technical info and datasheet for the analog touchscreen interface controller? I can find plenty of data for the LCD controller, but barely anything at all about the touch analog interface. Thanks

Of course there is always a level of reverse engineering. But many FPGA cores are based on original sources. E.g, the original Atari TIA schematics are available since long ago. I agree. On most cases emulators are actually more accurate because they are more mature. Also many FPGA developers don't target perfect accuracy.

IMHO there is a fundamental difference that is not directly tied to the source language. An emulator executes sequentially, while a FPGA core executes in parallel. And that won't change if you if you perform a C++ to VHDL conversion or a simulation of the FPGA core on a computer. Emulators don't emulate every single cycle because it wouldn't be efficient. This doesn't mean, of course, that one is better than the other. But it means that it would be very difficult for an emulator to be cycle accurate when connected externally. An emulator would have a hard time to reproduce sound, let alone video, with cycle accuracy and without lag. Simulating a SIO port (again, with cycle accuracy) to connect to a real Atari drive would even more difficult because the communication is bidirectional and here the latency is very relevant. Or even worse, try connecting an emulator to a real PBI device. On the other hand, an emulator can do lots of things that a FPGA core can't do, at least not without lot of pain. Such as pausing, loading and restoring state, etc.

It is a rare title, if you happen to have an original and a SCP setup, please contribute a dump. Even if it is not 100%, we might be able to recover the data. Having said that, some of us don't like too much people rewriting original disks. But of course, it is your disk and ultimately you make the decision.

It might be a replica, a clone, a compatible core, but certainly it is not emulation, even if not perfect ... You can have exact transistor level and bus timing accuracy, if you insist, but I don't think that it matters, and certainly that doesn't make the difference between being or not emulation. What it matters, IMHO, is if externally it is possible to detect any difference with the original system or not. Do you really care if the voltage levels are 5.5v, 3.2V or 1.8V? Or if the raising edge of some signal takes 100ns or 10ns? You don't, not unless it affects something that you can really detect externally. That's why we usually use the terms "cycle perfect" or "cycle accuracy", because that's what, IMHO, really matters. Of course, not every FPGA core is accurate, that is another matter.

Hi Larry, No, I don't think that using an Atari drive is the best imaging method. It is not only about advanced protections that are difficult to capture. A flux level device can record much more detailed and precise information. e.g., you can't dump the alignment of the tracks with respect to the index hole with a 1050, because it doesn't have index hole detection at all. Of course that using an Atari drive is very convenient and widely available. Many times I "toyed" with the idea to release a better 1050 imaging tool. But developing is time consuming, a PITA to debug, and probably not worth. So unlikely that this is going to happen, at least from my side. Note that you can currently use RespeQt to produce ATX images with an enhanced 1050, with some limitation of course. Just working is not enough for preservation purposes. Having said that, I verified many of the ATX images (feels like it was some centuries ago ) that were originally posted at Atarimania, not only for "just working" but also for being a correct clean dump. But of course, Farb's initiative have gone much further. These questions are not so simple to answer. No, as DjayBee said, the two images probably will not be identical. Even if you dump the very same disk multiple times, the images are unlikely to be identical because of minor timing differences produced by magnetic and mechanical imprecision. This is on top of the small differences between two different disks. And that's besides that many titles have multiple releases, sometimes with different copy protection methods. Not always, but certainly one image can be "better" than the other even when both work and, technically, both are correct.

Most people probably would consider it too high. But at the end of the day it is a very personal decision how much you want to spend on something like that. Just note that this game is not that rare, at least the ST release. It is famous as being rare for the well known issue mentioned above. But there are titles well much rarer than this one.