clemc at ccc.com
Thu Nov 8 01:14:20 AEST 2018
On Wed, Nov 7, 2018 at 9:09 AM <ron at ronnatalie.com> wrote:
> The DEC drivers just left off the last 72 sectors. There was no
> provision using them for block replacement.
Minor update -- *no dynamic replacement provision*. There was a standard
alone utility called BAD144 that implemented DEC Standard 144 (Bad
Blocks). What would happen is that the format was messed with the point a
bad block at on the reserved sectors.
This scheme caused nasty performance issues because seek schedualing was
defeated; and since UNIX did not originally obey DEC STD144, the standard
UNIX scheme in those days was buy 'perfect' media. BTW: the Ultrix team -
Fred Canter IIRC -- added support for BAD144, and I think DEC gave that
code to BSD evetually.
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