System and BBC Disk Compatability ?

[ChrisO]

I'm trying to get my System 3 upgrade working but I'm stuck because I don't have a format disc for it ?

It will read the catalogue off a BBC formated disc but files will not load. I know the underlaying format of the System, Atom and BBC disc is the same but is there some subtlety that stops a BBC disc working in the System (or Atom) ?

Bit of a long shot but does anybody have a copy of the System format disc ? The Atom version might work though I've not been able to find a copy of that either ?

Chris

[danielj]

At a guess, the directory needs to be changed to $ (which is root on a beeb) rather than . (which is root on the atom, and also I assume system?)

d.

[ChrisO]

Sadly its not that I knew to change the directory (qualifier in System speak) from $.

I'm getting a Disk error 18 whenever I try to access a file ?

[danielj]

That's sector not found iirc?

[ChrisO]

A bit more info - looks like the problem is with the BBC using longer addresses ?

If I INFO a file on the System 3 I get: 1900 8023 C1B78 C5B (load address, execution address, length, start sector)
the same thing on the BBC gives: FF1900 FF8023 001B78 05B

My BBC has Watford Electronics DFS 1.42 on it rather than standard BBC DFS maybe thats the problem ?

Would I have this problem with standard Acorn DFS ? Does this problem occur with Atom discs ?

[jgharston]

Atom/System DOS *is* DFS, with the exception that:

* DOS defaults to using directory " " (space) and DFS defaults to using directory "$" (dollar). Last time I checked, DFS allows *DIR " ", and DOS allows *SET$ (note: no space), which do the same thing (in opposite directions!).

* DFS uses 18-bit file addresses, DOS uses 16-bit file addresses. The extra 3xtwo bits are stored in the high bits of the sector start, so a DFS file with addresses &FFFFxxxx will be "seen" by DOS as having a sector start way way past the end of the disk and be humungously long. The solution is to ensure DFS files are shorter than 64K and have addresses &0000xxxx.

[ChrisO]

Sorted ! The problem was the Watford DFS on the BBC.

This morning I found an old Viglen Utilities disc which has format on it, using this to format a disc it is recognised and works on the System computer so at last I have a working System 3 .

I've also managed to get an 80 track PC style floppy (Teac FD55GFR) working just by changing the links to set it to 300rpm.

[Kazzie]

Excellent news.