XTIDE controller now available
cclist at sydex.com
Mon Oct 5 16:43:00 CDT 2009
On 5 Oct 2009 at 17:10, Dave McGuire wrote:
> New kludges were devised to exceed this ~137GB plateau
> (obviously), but I don't know how they work offhand because I've
> never designed with them.
Think "shadow registers"--instead of each 8-bit register in the task
file representing an 8-bit quantity, each will accept two consecutive
output or input commands and accept or return 16 bits. In other
words, each register has a flip-flop that directs I/O to either 8 bit
register. It's not pretty, but it works.
> Anyway, early BIOSs don't know how to deal with this, which is one
> of the things that makes this XTIDE controller special.
Well, one can also declare a minimal conventional CHS partition from
which one boots and then install a driver to access the remainder of
the drive. Something akin to the way a drive extender works. When I
had my AT, I used some 1224 cylinder MFM drives that early BIOSes
didn't know how to handle. So I booted from a smaller partition and
then loaded my own driver. With an RLL controller, that gave me a
whopping 250MB or so.
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