On 2015-03-19 14:13, Johnny Billquist wrote:
On 2015-03-19 04:21, Timothe Litt wrote:
On 18-Mar-15 20:34, Rich Alderson wrote:
[1] Developed mostly from RSX-11M, with a few nods to RSX-11D, at
least as far as the doc writers were concerned.
-11M, but -11D device drivers and a heavy dependence on event flags.
No memory mapping; it was a stripped-down environment.
1 RP04/6 disk dual ported; the 11 driver had to deal with 18-bit (576
byte)
formatted sectors.
The queued protocol provided access to unibus peripherals, including
async lines, card reader, LPT and (my secret contribution, a
battery-backed-up
TOY). This wasn't pure pass-thru; the 11 did a lot of the low-level
control and
presented abstracted devices.
This is getting rather far off-topic, but anyway...
Do you have any source for the claim about -11M with -11D device
drivers? As far as I know, one of the major differences between -11M and
-11D is just the device drivers, as the whole I/O subsystem was
redesigned in -11M, for a smaller memory footprint and better efficiency.
-11D could not run without an MMU, while -11M can. Thus it sounds
strange that you'd have -11M with -11D device drivers. I would suspect
that would be impossible, and in addition the -11D device drivers would
require more resources than their -11M counterparts, which would be
rather opposite of what was required of the 11/40 FE, which is rather
limited on resources.
My recollection of RSX-20F is that it very much feels like an unmapped
-11M system. Some changes because of the special requirements, but
nothing major.
Just re-read the RSX-20F manual (I had almost forgotten I had read it
before).
In that manual, it is described in pretty good detail that they
essentially just have an unmapped RSX-11M system. They added a device
driver for the DTE-20, and a service task connected to that, and then
just customized the whole thing.
The manual also mentions once or twice that RSX-20F also inherited
something from RSX-11D, but there is nothing in the manual explaining
what actually was inherited from -11D, so I'm not sure if I should take
that verbatim, or just a relationship note, since -11M itself was
designed based upon -11D.
Johnny
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