hbo@voodoo.ucsb.edu (09/13/89)
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I thought I'd share my recent experience in adding memory to the DS3100.
Before I begin let me say that this information is presented without warranty
as to its suitability, fitness, or applicability to your situation whatsoever.
Speaking of warranties, you might just void yours if you do this. I don't know.
If you screw up your machine trying this, on your head be it. I disclaim any
responsibility for your actions with regard to your computer systems. It's a
tough world. 8-) I have a diskless 3100 which I ordered from DEC with 12 Mb.
The machine came with 8Mb installed, and 4Mb additional which came packaged as
two 2Mb double sided SIMMs. Being the adventurous type, and wanting to compare
Sun and DEC in the area of peripherals and expansion, I decided to do the
installation myself. What follows is a blow-by-blow description of the process.
Opening the DS3100's case was pretty easy. Loosening two screws on the back
of the machine sufficed to free the top cover, which slid off toward the back.
I had slight trouble with the internal SCSI cable catching against the cover,
but nothing serious. Removing the cover exposed the power supply (on the
left looking at the machine from the front) and the internal disk bay. At
this point I whipped out my handy 3M antistatic grounding wrist strap and
glopped it onto the chassis of the machine. I had kept the wall plug attached
so as to maintain a good ground. Make sure the power switch stays OFF if you do
this!! The disk bay was empty on my machine, and I could easily see where the
internal SCSI cable connected to the motherboard below. This I disconnected
(noting that it was a keyed connector. Hooray!) along with the internal power
cable where it issued from the power supply. This left 5 retainer type slotted
screws to disconnect. Two in front, two in back and one on the power supply
casing. Finally I loosened three phillips head screws along the right side
(again looking from the front) of the machine. At this point, I was able to
lift the disk bay platform out of the machine, exposing the motherboard.
The RAM slots are next to the power supply. They are extremely hard
to miss. One thing that might be hard to miss, are the numbers along the
left side (looking towards the back) of the SIMM slots these tell you where
to install the next set of SIMMs. I was adding 4 megs to an 8 meg machine,
so my two 2 Mb SIMMS went into slots 5 and 6. I'm not sure if you need to
add RAM in 2 or 4mb increments, but I knew my particular configuration was
supported, since I got it from DEC. Attaching SIMMS has been covered in a
previous message (thanks!) but I'll recap here. You have to place the SIMM
into the slot diagonally, leaning toward the back of the machine. Then,
after making sure the SIMM is level in the slot, and that the holes in the
PC board line up with the clips on the slot, you "roll" the SIMM into the
slot by moving its top toward the front of the machine. It's actually easier
to do than to explain.
Closing up involves reversing the disassembly. Take care to ensure the
internal power cable doesn't bind as you place the diskbay platform back in
the machine. Reattach the screws (they should all still be on the platform.
Nice touch!) and reconnect the SCSI and power cables. At this point I pulled
the antistatic strap off, and unplugged the AC power cord. Slide the cover
back on, taking care the SCSI cable doesn't bind. Reattach the two screws
on the back and you're set!
You need to change the physmem parameter in your system configuration
file in /usr/sys/conf/mips/ to reflect the new amount of RAM. Run config
after this and before typing make in the appropriate directory under
/usr/sys/b.mips/ to build a new kernal. This is all covered in the Ultrix
documentation.
As noted here, DECwindows runs a LOT faster with 12Mb vs 8Mb. I'm happy
with how easy it was to add the extra RAM. It compares favorably with the
experience I've had with the Sun 4. Now if DEC would just make adding foreign
disks as easy ....
--
Howard Owen, Computer Systems Manager internet: hbo@nobbs.ucsb.edu
Physics Computer Services BITNET: HBO@VOODOO.BITNET
University of California, Santa Barbara HEPNET/SPAN: VOODOO::HBO
"I am not a pay TV service!" 805-961-8366 (work)