Hakan Thorngren wrote:
> 
> There is a possibility that I can obtain a Sun 3/280, but I do not know
> how complete the machine is.  I had a look at it yesterday and if I
> describe it, maybe someone who are familiar with it can enlight me?

I'm not as much of an expert as some folks on this list, but I'll give
it a shot...

> It is a rather cubic thing with the chassis bare all around with a
> loose front.  There is no case  of any kind.  Is it supposed to be mounted
> in some kind of cabinet?

The 3/280s are made for rackmounting in standard 19" equipment racks. As
far as I know, there is no pretty plastic exterior with the exception of
a removable faceplate. These machines were made to be racked up in a
systems room where they didn't have to be seen. The 3/260 is the same
machine, I believe, but in a more cosmetically appealing deskside case.

> There are some boards mounted in it and one empty hole, possibly a
> board that has been taken from it.
> The boards appear to be:
> 1. Some kind of I/O board with the standard connectors for keyboard, monitor,
>    ethernet and serial ports.

I think this is probably the CPU board. All the 3/280 CPU boards I've
ever seen have the keyboard, video, AUI, and serial ports onboard. I've
never seen a 3/280 with an I/O card.

> 2. A SCSI board with the old style SUN SCSI connector.
> 3. Two(?) CPU boards.  After reading the little information I could
>    find in FAQs, there should only be a single 68020?

These are probably memory cards. You can look up the Sun part numbers in
the FAQ to check this. As I recall, they have DIP switches on the panel
that configure them as consecutive memory modules 1,2,etc, along with
some green LEDs that indicate communication with the CPU. I think
8MB/board was the standard configuration.

> The machine appears to be "naked" without disks and tape.

Just makes it more fun!

> Now my questions:
> 
> 1. Why are there two CPU boards?

I don't think there are --see above.

> 2. Is the missing board likely to be have been a memory board?

Maybe, but I'd guess maybe a xylogics SMD disk controller or something.

> 3. Is it possible to buy a memory board for it today at a reasonable price?

I've never tried. A good place to buy used Sun stuff is the Sun 'wanted'
newsgroup: comp.sys.sun.wanted.

> 4. How much memory is it likely that it have in its current configuration?
>    (Hooking it up and get it running would be a major task as I would have
>    to borrow a monitor from another place and move the heavy machine to
>    a different location.)

My guess is that you have 16MB of RAM between the two boards which I
theorize are 8MB each. You can use a dumb terminal on serial port A
(9600,N,8,1) instead of a monitor if you only want text mode. Otherwise
you need a high-resolution monochrome unit (Sun's lower-res monochrome
monitors that you use with 3/50s and such won't work).

> 5. How should the front be attached?

If you're referring to the plastic faceplate, mine just snaps on.

> 6. I have an Amiga 3000 running NetBSD, I got the impression that I can
>    use it to boot the SUN as a diskless over the network.
>    If I purchase a new SCSI disk, can I format it on the SUN (or the Amiga)
>    and use it on the SUN?

Yes, you can netboot the 3/280 from another server, then use it to
format a drive. This is a tricky process, but it's a great learning
experience.

> 7. There are SCSI In/Out connectors on the back, what are they for?

I'm not sure about this. I don't think I've ever seen a SCSI board with
IN and OUT connectors. Are you certain this is a SCSI board?

> 8. Is it very power hungry?  I do not want my elctricity bill to sky-rocket...

I don't know. Someone else have an idea?

Some things you may or may not already know: The order in which the
cards are inserted into the backplane is important! The backplane has to
be jumpered properly and certain cards will only run in certain slots.
So if you think the cards have been rearranged, you'll want to get the
slot info and make sure they're in the right places. The released
version of the hardware FAQ does not have the info for this particular
chassis. Perhaps the 'working' version has this info now. If you need to
move boards, be _very_ careful when plugging them into the backplane. If
you bend any pins on the connector you will most likely smoke the board
(been there, done that). Also, be sure to use the steel blanks in empty
slots: they are crucial to the airflow from the four fans in the bottom
of the unit.

Good luck with this machine! If you need more info, let me know. Once
September rolls around I will be back at school where I have access to
quite a bit of documentation on the 3/280 and associated hardware. Email
me at adk0212@rit.edu and may be able to help you out.

-- Adam