QSIC update and request
dab at froghouse.org
Tue Jan 2 12:02:23 CST 2018
On 01/02/2018 12:45 PM, Toby Thain via cctalk wrote:
> If the documentation is good enough, people in the community will be
> able to provide the software.
The quick answer is that it's pretty simple. We take the
cylinder/head/sector addresses and consider them a Linear Block
Address. Then we look around the device registers and pick up a few
more bits that were unused in the RP11 and we end up with a 28-bit
Linear Block Address which works out to a ridiculously huge disk for any
PDP-11 ever conceived. But yeah, we'll document it.
There will also be an entirely new programming interface into the QSIC
itself, mainly having to do with configuration (like whether or not the
RP11 implementation is stock or extended and how portions of the SD
cards are mapped to various disk packs mounted on the emulated disk
drives). I intend to write that up too so that people are able to write
programs for their favorite OS that drive the device however they wish.
I may joke about pointing people to the source to figure out how it
works (it was hard to write, it should be hard to read) but I actually
quite like well-done documentation and will endeavor to produce some.
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