Another file format description page

clausjahn · May 2008

Dear Forum readers,

I'm hosting another description site of ZX-Spectrum emulator file format descriptions, where you may find several file formats in more detail. I'm trying to enhance and to extend this homepage from time to time.
My plan is to finally describe all known formats that way, or to place links to other sides which show good explanation.

http://www.zxmodules.de -> Section "file formats"

Please tell me what could be done better. Thanks in advance,

Claus.

Laser · May 2008

First of all, thank you for attempting to collect this information together. There are other resources doing this too, but the more the merrier.

Just a few comments on improvements:

1) Where fields are not BYTE, but instead WORD/LONG etc, you must specify big or little endian, else the information is not directly useful.

2) Something to say which emulator/utility is the primary creator of these files, and which currently support them (I know you have mentioned the originating author in a couple of places). This would allow people to judge whether it is worth supporting a format. Benefits and shortcomings between similar formats may also be useful.

3) Keep the format selector frame at the top so it is easy to flip through the formats (or remove frame and make it into a menu on each page).

4) No disrespect, but I get the impression that some of the information is just copy+pasted from another source. If you want your resource to be more attractive than someone else's, you need to make the comments less cryptic and the presentation more intuitive than that other source.

Ralf · May 2008

Just a few comments:...

RZX is not a tape format. It is used to record keystrokes, so games being completed can be watched.

I have never seen HOB extension , but I have seen strange .$ extension for Hobeta files (whatever they are)

To learn more about Spectrum file formats you can check:

http://www.tjornov.dk/spectrum/faq/fileform.html

clausjahn · May 2008

First of all, thanks for the good answers (hopefully more will follow).

1) Where fields are not BYTE, but instead WORD/LONG etc, you must specify big or little endian, else the information is not directly useful.

Yes, Laser, that's true. I will place a legend of these byte, word etc. tags somewhere in the bottom area. Now, Word means little endian (LSB first), and in the cases of MSB first, I have split the Word into 2 bytes instead. I will correct this.

2) Something to say which emulator/utility is the primary creator of these files, and which currently support them (I know you have mentioned the originating author in a couple of places). This would allow people to judge whether it is worth supporting a format. Benefits and shortcomings between similar formats may also be useful.

Indeed. A good improvement. I will add some additional notes which progams (utilities, emulators) support or create the format. But I can do this only for file types where I know the facts, of course.

3) Keep the format selector frame at the top so it is easy to flip through the formats (or remove frame and make it into a menu on each page).

Yes, I already thought about fixing the top line. Well, it's no problem. Will be done! :-)

4) No disrespect, but I get the impression that some of the information is just copy+pasted from another source.

I never made it that way, even if it looks like so. Of course the information of some file formats I have taken from official file format description, but what you see on my website is re-interpreted from my file reading routines. In cases where there's a good file format description existing, I will link to that pages (e.g. Ramsoft's TZX description, etc.).

If you want your resource to be more attractive than someone else's, you need to make the comments less cryptic and the presentation more intuitive than that other source.

That's exactly my opinion. But the question is: How. When making my next website update, I will look around all file formats and try to improve cryptic sections. But for improving the look of the format tables, I need some good ideas. :-)
I'm also a bit unhappy about the offset indicators ????. That appears all the time when the format structure becomes various. Also, the way, I have placed Case-structures, could be done much better.

RZX is not a tape format. It is used to record keystrokes, so games being completed can be watched.

Oh yes. That's true. I know that but it was an old entry. Will be corrected.

I have never seen HOB extension , but I have seen strange .$ extension for Hobeta files (whatever they are)

Yes, also true. I have already implemented the support of the $-files in my own programs (btw. $b is standing for Basic files, $c for code files and $d for data files) and I don't know why I did not yet corrected this HOB bug on the format overview.

To learn more about Spectrum file formats you can check:
http://www.tjornov.dk/spectrum/faq/fileform.html

Thx. I already know this source and visited it quite often. ;-)

Thanks for all the comments (and for those which follow). I will annouce when my changes were done.

Claus.

Laser · May 2008

clausjahn wrote: »

Laser wrote: »

If you want your resource to be more attractive than someone else's, you need to make the comments less cryptic and the presentation more intuitive than that other source.

That's exactly my opinion. But the question is: How.

Well, let me take the SNP format description as an example...

You have a field saying WORD: af, but the comment is "f, a". Now what does that mean? I could guess, but the whole point of documenting it is to be clear.

At 49170/1 you have "NOT iffX" with a comment of "NOT --> iffX". The comment doesn't add anything, and the description is a bit vague anyway: A BYTE to contain a BIT, inverted(?). 0x00 and 0xFF? 0x00 and 0x01? Doesn't matter? etc. In other tables you use "EI/DI", which logic sense maps to which?

At 49152 you have OUT ULA, bits 0..2. Is that bits 0..2 of the BYTE, or 0..2 of the ULA, or both? Are bits 7-3 of the ULA provided somewhere else, or default to 1 or 0? Again, I could guess, but that's not the point.

A short comment about reserved bytes being 0x00 or <whatever> should also be made.

On the SNA page, you have no comment about how to get the PC value, or the consequences of that.

Please don't think I am specifically complaining about your efforts to document these things. Other efforts are just the same. This is why I say you should try to make it better, clearer, more intuitive and trustworthy. Too many specifications of this type of thing are out of date, slightly incorrect, difficult to understand, only cover the primary formats, etc. I would love to see your site become a really good quality resource for these formats. Pretend the person reading it has no access to files of the format to check for himself, but still has to write a program capable of reading and writing a 100% compatible file.

clausjahn · May 2008

Thanks, Laser.
You may think I become angry reading your words? Definitely NOT.
I agree with you in ALL points. Let me take one more try and in a couple of days, take a closer look again.

Thanks and hugs, ;-)

Claus.

clausjahn · June 2008

Dear folks,

depending on the various improvement recommendations of Laser, I changed the file format description today. I have changed 4 file format pages.

Laser, if you would like to take a look at my beginning and give me a feedback whether it is (hopefully at least a bit) better than the previous version? I would be pleased.

I will make some changes during the next weeks, especially adding the now disabled formats again.

Especially the Z80 formats need an update, as I did not describe (nor support it in ZX-Modules) the alterations from other emulators.

And thanks God, Jon Needle announced the new SZX format specification. ;-)

Kind regards,

Claus.

clausjahn · July 2008

I have renewed my file format specification homepage again.
It can be found at

http://home.arcor.de/clausjahn/spectrum/fileformats/fileformatsframe.html

or via menu directly from my domain www.zxmodules.de

I will definitely continuing making it better and clearer.

Kind regards,

Claus.

Another file format description page

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