>Sorry for the off-topic posting, but this is the most relevant forum I
>can think of for asking PDP-11 questions.

classiccmp mailing list and comp.sys.dec
newsgroup may be better.

>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.

You need to know what board(s) you have inside
and then corss check against the field guide
at http://world.std.com/~mbg/pdp11-field-guide.txt

Once you know what you have, you can find (much) more
detailed documentation by following the various
pointers at http://www.decdocs.org/

>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?

Sounds like you have an RD53. You may be able to get
an RD54 (~159MB) otherwise you'll have to
go for a 3rd party ESDI or SCSI disk.

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

Way, way different. Some PDP-10s had a PDP-11 as
a front end, but that's about the only link!

Antonio