On June 11, Chris Wareham wrote:
> I have just acquired one of these machines, which looks quite modern but
> appears to be of 1979 vintage. Does anyone know how I definitively work
> out what model it is? As I say it looks quite modern, but a sticker on
> the back say 11C23 which I guess makes it an 11/23. I poked around the
> PUPS website, and can't find any pictures to confirm this.

  Yup, that's a pdp11/23.  A good machine to start with, with an easy
upgrade path to the much faster J11-based processors like the
pdp11/73.  A nice score I'd say, no matter what the config.

> It has a 75Mb drive and 512Kb of RAM, and I hope to stick 2.11BSD on it.
> Ideally I would like to increase the ram to 1Mb (or more if at all
> possible), and the disk capacity to 200Mb. Does anyone know of a source
> of memory and disks for these beasts?

  You'll basically need to get "plugged in" to the pdp11
"community"...this mailing list is a good place to start; a lot of us
here have pdp11 goodies and might be able to help you out.

  The pdp11/23 can address up to 4MB of RAM, though most have much less
than that.  For drives, if you stick with small-form-factor DEC disk
controllers you can go up to an RD54 (159MB).  Don't entertain
thoughts of looking for a Qbus SCSI board unless you want to shell out
serious dough...they are in high demand (both commercially and amongst
hobbyists) and carry very high price tags as a result.

> would it be worth me subscribing to the port-pdp10 list, or are the
> PDP-10 and 11 radically different (apart from in size)?

  The pdp10 and pdp11 families are about as different as machines can
be...they can share some peripherals but that's about it.

  I'm about to head to sleep right now (been another very long day of
8051 assembler programming) but if you have any specific questions
you're welcome to send me an email.  I have a large quantity of pdp11
gear and lots of reference materials here.

      -Dave

-- 
Dave McGuire                       "*BURRRP!*  Mmm...tastes like cannoli,
St. Petersburg, FL                    smells like garlic!" -Sridhar