ATEX PDP-11 For Sale in Houston

Ethan Dicks ethan.dicks at
Tue Apr 16 11:25:04 CDT 2019

On Tue, Apr 16, 2019 at 10:49 AM Jon Elson via cctalk
<cctalk at> wrote:
> On 04/15/2019 12:08 PM, Thomas Raguso via cctalk wrote:
> > I am selling an Atex PDP-11/34. The computer has: J11 CPU, 11 MB RAM, 2
> > BA11-LE expansion chassis, a second backplane, an SMD disk controller and
> > LAN hardware.
> >
> 11 MB ram on a PDP-11?  Is that possible?

No.  On VCFED, I saw a post that said there were 176 256Kbit chips on
it.  I work the math as:

11 chips == 256Kbytes (with ECC)
44 chips == 1MBytes (with ECC)
176 chips == 4MBytes (with ECC).

I have no idea where 11MB came from.

> Also, was the J11 used in the 11/34?  Wasn't the /34 all TTL?

The /34 KD11-E is a two-board set with an ALU implemented with 74181
chips.  This J-11 board is definitely 3rd party and much later.


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