[Coco] Nitros-9 Dir size

[Bob Devries]

Luis,

are you referring to the PD.SAS setting in the RBFMan options sections 
(refer page 5-7 of OS-9 Technical reference), which is also in the Device 
Descriptor (as IT.SAS at offset $20 on page 5-9)?

Although this appears to refer to files, it should be noted that a directory 
in OS-9 is just a special purpose file.

Regards, Bob Devries
Dalby, QLD, Australia

----- Original Message ----- 
From: "Luis Fernández" <luis46coco at hotmail.com>
To: "COCO" <coco at maltedmedia.com>
Sent: Saturday, March 30, 2013 1:22 PM
Subject: Re: [Coco] Nitros-9 Dir size


I have understood that they reserve 9 sectors, one header and 8 for 64 names
each name uses 29 bytes + 3 Start sector number of the file, total 32 bytes
8 names fit by sector

the problem is that not what is the command to create a different initial 
size or other size subdir

> From: gheskett at wdtv.com
> To: coco at maltedmedia.com
> Date: Fri, 29 Mar 2013 20:02:30 -0400
> Subject: Re: [Coco] Nitros-9 Dir size
>
> 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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