Re: P00-format + new D-format

From: Ruud Baltissen (
Date: 1998-10-13 21:44:41

Hallo Andre,

> What I think you are going to do is: You make a 16M disk image and
> your program writes the files like on a D64 file only more sectors and
> tracks, right? 


> Well, this B-R thing is the only advantage I can see of using a 16M disk 
> image instead of using the filesystem directly. Actually I would not want 
> to waste 16M for a single image disk that is probably halfway empty or so...

I've some 20 MB disks and loose 286-boards laying around doing nothing at 
all. You may guess what I'm going to do with them....

> What I mean with using the filesystem directly using the hosts
> filesystem, producing single .P** or whatever files for each file saved.
> The VICE emulator handles this fine for example.
> This way no empty space is wasted for a more or less empty disk image.
> Only if full compatibility is needed one uses .d64 images. But
> there is no use creating a new type of disk image, because there is 
> no program compatible to it.

But more compatible then a P00-file, IMHO.

> Only the .D** files are like disk images with tracks/sector
> For a bit more on the old disks see
> Sorry, don't have the table of which track has how many sectors.

Schade. Kein Problem, hat Zeit. But I did encounter another problem 
concerning D16: what about the BAM? Can anybody tell me how the 1581 
handles this? My first idea is to reserve 9 complete sectors for this: one 
for the free sectors on every track and 8 for bitwise representation of 
each track.

Hallo Per,
> I should be able to dig that out if someone really needs to know.

If you do have at hand, please do.

Anyway I digged up this:

Drive:     Total bytes:  Dir entries:  sectors per track:  tracks: blocks

8050        533248        224           23 to 29            77      2083
2040/3040   176640        152           17 to 21            35      690
4040        174848        144           17 to 21            35      683

The DISK REFERENCE MANUAL also gives some numbers about the harddisks:
                     9090      9060
Formatted storage    7.47 MB   4.98 MB
Cylindres (Tracks)   153       153
Sectors/Cylinder     128       192
Sectors per track    32        32
bytes per sector     256       256
Free blocks          29162     19942

I cannot figure out what they mean.

Groetjes, Ruud

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