🚀 go-pugleaf

mfroedge@lunatix.uucp (Maxwell Froedge) writes:



>1.  Where can I find software and documentation for these guys?

	Of course, you can find them through DEC.  The RT-11
	order number is QJ013 (or at least it was, last time
	I looked).  Most recent version is V5.6, released
	earlier this year.

>2.  Can I change the floppies to 1.2 meg drives.  I seem to
>remember a DEC PDP with a 1.2 meg floppy.

	If you mean the RX33 - yes, as long as you have an
	RQDX3 interface.

>3.  These are 11/23 processors.  I have 256K NEC 3rd cards
>installed.  What is the maxium memory these support (both the NEC
>cards and the 11/23 processor.)  The system is a Q-bus.

	There are two things contributing to whether your
	system is 18-bit or 22-bit.  First, the CPU.  If you
	have a KDF11-B (quad-high module), you have 22-bit
	support on-board.  If it is a KDF11-A (rev.c), you
	also have 22-bit support.  KDF11-A (rev.a) is 18-bit
	only.  Second, the backplane.  Since you mentioned they
	are MicroPDP-11's, I know they do have 22-bit support.
	The backplane is Q-CD for the first three slots and
	'zig-zag' q-q for the remaining slots.

	In a 22-bit machine, you can have up to 4mb of memory.

					Megan Gentry
					(RT-11 developer of 15 years)

In article <BznHn7.A5F@world.std.com>, mbg@world.std.com (Megan B Gentry) writes:
> mfroedge@lunatix.uucp (Maxwell Froedge) writes:
...
> 	There are two things contributing to whether your
> 	system is 18-bit or 22-bit.  First, the CPU.  If you
> 	have a KDF11-B (quad-high module), you have 22-bit
> 	support on-board.  If it is a KDF11-A (rev.c), you
> 	also have 22-bit support.  KDF11-A (rev.a) is 18-bit
> 	only.

Bzzt, wrong. The rev c KDF11-A was the only 18 bit CPU in the 23s, despite
DEC propaganda of the time. ( "No, you have to pay $$$$ for a 23+ for that... ")
You will also have to chuck any 18-bit memory or controlers if you want more
than 128KW. Note, 128, not 124. You can have all 128KW in a Qbus.

~Paul

zrepachol@cc.curtin.edu.au writes:

>In article <BznHn7.A5F@world.std.com>, mbg@world.std.com (Megan B Gentry) writes:
>> mfroedge@lunatix.uucp (Maxwell Froedge) writes:
>...
>> 	There are two things contributing to whether your
>> 	system is 18-bit or 22-bit.  First, the CPU.  If you
>> 	have a KDF11-B (quad-high module), you have 22-bit
>> 	support on-board.  If it is a KDF11-A (rev.c), you
>> 	also have 22-bit support.  KDF11-A (rev.a) is 18-bit
>> 	only.

>Bzzt, wrong. The rev c KDF11-A was the only 18 bit CPU in the 23s, despite
>DEC propaganda of the time. ( "No, you have to pay $$$$ for a 23+ for that... ")
>You will also have to chuck any 18-bit memory or controlers if you want more
>than 128KW. Note, 128, not 124. You can have all 128KW in a Qbus.

Sorry, I have a KDF11-A (rev.c) which has MUCH more than 128kw on it
at home...  The KDF11-A (rev.c) carried the extra four addressing
lines out to the bus, where the rev.a had not.  The rev.a could
only address 18-bits because those addressing lines stopped on-board.

(I seem to remember someone hacking a rev.a board so that the extra
four lines were carried to the bus, but I don't remember who.  I think
the lines had to pass through inverters first.)

					Megan