[Coco] Hard drive formatting

[Gene Heskett]

On Monday 07 September 2015 13:03:17 George Ramsower wrote:

>   Many years ago, had to format a SCSI hard drive for use on my
> Coco(OS9). I seem to recall that all the info would be entered into
> the program so it could  properly do that formatting.
>   I also understand that some drives will format themselves if
> properly instructed.
>
>   So, basically I'm asking as a newbie about how to format a SCSI hard
> drive. I've found the specs on this unit and I can find specs on the
> other two I have but I have no idea now, on how to do this.
>
>   Suggestions, software and assistance/advice are needed at this time.
>
> George R.

Its been quite a while since any hard drive could be formatted, George.  
That takes special, factory only tools to do it.

I cannot, have not ever formatted that pair of 1Gb Seagate Hawks I use on 
my coco3.  They may kill a few seconds, then report the physical format 
is done, but nothing was written.  Its also been 15 or more years since 
a 256 byte sector could be written, but our modern os9 drivers write one 
256 byte sectors data in half a 512 byte hard drive sector, and the next 
sequential os9 sector is written to the high half of a 512 byte sector.

That is done by using a 512 byte buffer, the sector is read into it, any 
modifications are done in this buffer, and when the file is closed, that 
512byte sector is written to the disk.

Not all drivers do that, some just waste the high half of the sector.

What it simmers down to is the format does a "logical" format, which 
consists of laying down the root filesystem from which everything else 
grows as the drive is used.

Cheers, Gene Heskett
-- 
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