[Coco] Nitros-9 Dir size

[Gene Heskett]

On Friday 29 March 2013 19:42:17 Luis Fernández did opine:

> In a new disk NitrOS-9 sectors size reserved for ROOT Dir is 9 sectors,
> 1 sector for the sequence of sectors and 8 for file names.
> 
The last time I walked through that code, the initial allocation from the 
FAT was 8 sectors, and it used the first one for the file descriptor 
sector.

This means there are only 54 named entries (and the . and .. entries) 
allowable in this initial disk allocation.  I looked see it there was some 
way I could use the SAS in the descriptor to enlarge this, but it would 
have been a major re-write.

So generally, the 55th name entry in the root directory will then get 
another SAS sized allocation.  For files I recommend a SAS of at least $20 
to cut down on file fragmentation as it can be allocated, even set at $FF 
if there is enough room on the disk, because whatever is not used will be 
released as part of the file closing, so you don't waste a lot of disk by 
reserving 254 sectors but only using 12.  But a directory allocation is 
fixed lenght forever, so making a 254 (dmode sas=FE /device) sector 
directory is, particularly on floppies, a huge waste.  When you go past the 
end of the original 54 names, leave sas at 8 because thats room enough for 
64 additional names /in that directory extension/.  Big HD's of course are 
an entirely different horse, so my default sas setting on the pair of 1Gb 
seagates is $20.

> The point is, there is a parameter in OS9/Nitros-9 allow me to create
> new disks / Dir or Sub-Directories more or less of sectors (more or
> less amount of file names), initial reserve
> 
> Of course I know this can be expanded by adding sectors to sectors dir
> sequence, but initially I say?
> 
Format makes the original root dir, and its fixed at an FD and 7 for data.

After that, for all other new directories, and extensions to existing ones, 
the size is controlled by IT.SAS in that drive/partitions descriptor.

Cheers, Gene
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