flash (or ide) storage for unibus 11?
radioengr at gmail.com
Tue Nov 24 03:01:00 CST 2015
On 11/24/2015 12:46 AM, Johnny Billquist wrote:
> On 2015-11-23 20:30, David Bridgham wrote:
>>> For a classic/straightforward programming interface, the Massbus
>>> disks (RP04 and successors) are a good choice. That will take
>>> you just over 500 MB, if you emulate the layout of the RP07.
>> Current thinking (at least my current thinking) is RK11 first then
>> probably RP11, both optionally extended to support Q22 addresses.
>> Also something we're calling the RQ11 which will be our "native"
>> interface with variable sized disks with a 32-bit linear block
>> address giving 2TB disks for those who are willing and able to
>> write their own device drivers. Finally, most likely the RH11 for
>> some Massbus disks with 22-bit addressing. After that, I'm
>> thinking to call it good and move on to other projects though I'm
>> certainly willing to talk to anyone who has a particular disk
>> controller they want to implement.
> 22-bit addressing is not possible on the Unibus. The RH70, which is
> the massbus controller for the 11/70 do 22-bit addressing, but it
> manages that by not sitting on the Unibus.
The RH11 has 'paging' on the controller. It can translate between Unibus
addresses and memory addresses.
> Your native interface have the additional problem that in addition to
> requiring people to write their own device driver for any OS usage,
> it will be rather difficult to get booting from it, since that
> require special support.
> RK11 and RP11, while fairly simple, are also very small devices. Is
> that useful for anything beyond it being a fun exercise? Massbus is a
> bit more useful, as it at least gives some larger devices, but you
> need to implement each device. Each has its own device identity, with
> its own geometry, which you need to support. There is some rather
> non-generic things around massbus.
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