PDP-11 Memory

Sat Jan 12 18:34:57 CST 2019

On 1/12/19 6:45 PM, allison via cctalk wrote:
> On 01/12/2019 05:03 PM, Bill Gunshannon via cctalk wrote:
>> On 1/12/19 4:30 PM, allison via cctalk wrote:
>>> On 01/12/2019 04:14 PM, Bill Gunshannon via cctalk wrote:
>>>> On 1/12/19 2:25 PM, allison via cctalk wrote:
>>>>> On 01/12/2019 12:29 PM, Pete Turnbull via cctalk wrote:
>>>>>> On 12/01/2019 01:24, Zane Healy via cctalk wrote:
>>>>>>
>>>>>>> I’m pretty sure you could get the /23+, /53, /73, /83, and /93 in
>>>>>>> either a BA23 or a BA123.  I have an actual badged BA23 pedestal for
>>>>>>> my /23+.
>>>>>> I'm fairly certain all microPDP-11/23+ systems were only sold in BA23
>>>>>> boxes, and I think microPDP-11/73 and the later, cheaper, cut-down
>>>>>> 11/53 were as well.  But almost all the 11/83 systems I've ever seen
>>>>>> were in BA123 boxes, though they did sell some in BA23 pedestals -
>>>>>> I've got one.
>>>>>>
>>>>> Pete,
>>>>>
>>>>> Your right the 11/23+ showed up on a lot of boxes but not the BA123
>>>>> though it would fit.
>>>> My 11/23+ is in a box labeled PDP-11/23PLUS on the front with
>>>> three toggle switches.  :-)  It has a 9276-A backplane labeled
>>>> OPTION 11/23B. It is a 9 slot, Q22 A-B-C-D .  That's the home
>>>> for my next system which will (hopefully) have 2 meg of memory,
>>>> a DEQNA and an Andromeda Card for a small hard disk and 8" floppy.
>>> BA11 box with one of the usual two common backplanes or standard BA23.
>>>
>>> Problem with DEQNA is what OS?  RT11 does nothing with it.  RSX-11
>>> I don't have a recent enough version so its often unused/
>> My only problem is I have 3 DEQNA and 1 DELQA.  I thought I read
>> somewhere recently that the DEQNA was the better of the two.
> DELQA replace the DEQNA as often they didn't work, high failure rate in
> service.
> There was also a DAta corruption bug that also turned up so DELQA was the
> replacement.

And then there was the old how to crash a PDP-11 (and I think early
VAX as well) by flooding a network.  Luckily all of mine will be on
switches and accidental flooding won't happen.  Of course that doesn't
mean I won;t try it just for fun.

> 
>> As for software, what about the Kent TCPIP package?  Will that
>> not work with the DEQNA?  I thought the two Ethernet controllers
>> for QBUS were functionally the same.
> Roughly as the DEQNA carried a mop boot loader but it didn't use it for
> RT-11.  RT does nto that I know of through 5.4 support the Ni device
> for any internal use, an application can but you get to write code and
> create a Decnet endpoint.

I don't think any common PDP-11 OS could net boot, but that doesn't
mean I can't do it myself.  I was wondering how hard it would be to
get Xinu to netboot rather than boot over a serial line.  :-)

> 
> I know of now IP stacks for PDP11, they may exist but not in my vocabulary.
> I can't see why not though but then you likely need UNIX and what version?

More than one as far as I know.  Johnny Billquist did one for RSX.
I thought Process Software had one before they settled on only VMS.
TCPIP for TSX and RT-11 from kent.edu. (I have never used it but I
have been told by people more knowledgeable than myslf that is works
really well.  I plan to find out now.)

And, of course, Ultrix-11 and BSD2.11 both have full networking.

> 
> I know V6 doesn't and I have that on RL02.
>> And, while we are at it, if I type BOOT XH does it look for a
>> MOP Server?
> For RSX it may work as RSX later versions supported networking.

I am not worried about what will be downloaded (yet), just what typing
BOOT XH actually does.  I guess I will noe for sure when I try it with
a network  monitor running.  If it works as I hope, I have a lot of
experience MOP Booting other devices.

> 
>>>> I also plan on another small 11/23 with 128KW of memory and an
>>>> 18 bit backplane so I can use the RX02 emulator.  And, probably
>>>> an Andromeda in there, too
>>>>
>>>>
>>>> To bring my part of this discussion to an end, I now have a BA23
>>>> MicroPDP box with an 11/73 CPU, 4 meg of memory, DHV11 for eight
>>>> serial lines (probably only use one to talk to a TU58 emulator
>>>> but the DHV11 was just sitting there looking lonely) a DEQNA
>>>> and a CMD SCSI Controller set for 6 disks and one tape.  Only
>>>> thing it lacks at this point is software.
>>> The TU58 like a responsive IO a DLV11J is a better choice for console and DD
>>> and works best if first card after the memory (early in the interrupt
>>> grant chain).
>> My 11/73 only has a console, thus the need for the DHV11 but really
>> only one port. (Although I may try putting multiple serial ports in
>> all the boxes and doing some "networking" over them.  :-)
> Right the 11/23 and later quad 11/73 have console the dual width without
> pulling out
> the rack to look did not.

Not my 11/73.  The 23's have two ports but the 73 only had one.

> 
>>> The simulators are faster than tu58 so it makes for fewer retries.
>>> I use DHV11 for terminal and modem lines (slower stuff).
>>>> On to my next project.
>>>>
>>>> Thanks for all the help.  I had forgotten just how much fun
>>>> real computers were compared to PC's and MAC's.
>>> Yes they are.  Their performance without all the gui gunk is often a
>>> suprize to many that have not worked with them.
> 
> I've had people running stuff on a 486/dx33 with 8mb (win3.11 as DOS 5.22)
> and RT11 on PDP11/23 with 512kbyte  and totally blew their minds.  The 11
> ran a lot of stuff that the PC could and was faster.  Then they got to
> see it as
> a multiuser system with RSTS, push them over with a feather.   The
> multitasking and multiuser aspect shows it off.  Side effect of time and
> maturity of OS and Instruction set with good hardware.
> 
> The Storage systems were better and MMU made swapping and memory
> management cleaner so beat the tar off segmentation and early Intel 32bit
> (386/486 era) as it didn't do context switching at all well (slow).
> 
> Once graphics found home then it had to a VAX/VMS on a 3100/GPX
> and a color tube to get the same level wow.
> 
>>> More surprising than most would accept.  It's not a PDP-11 but
>>> I have a 6809 that was sold as a toy for running games that I have
>>> had 4 remote login sessions and a web server running on.  And
>>> that was with networked disks and all remote access over a 115K
>>> serial line on a bitbanger port!!  I would love to see a version
>>> of that OS on the PDP-11.
>>>
> The 6809 (hitachi 63B09) are about as close to PDP11 in general
> structure and
> instruction set and could boogy.   The were a cusp 16 bitter (not really
> but close).

We;ll see.  I may take a shot at doing a PDP-11 port of NitrOS9.  :-)
I would also like to do early MINIX.  And, netbooting of almost
anything with some form of disk server for diskless running.
Amazing what fun you can have when your not doing it for money.

> 
> The 8088/86 was not wonderful, and what came after had all the side baggage
> to not help.   At that time I was voting for 68000 to win!

Too bad Motorola had scruples.  We got stuck with Intel.

bill