Convex documentation online (C220 arrived)

Camiel Vanderhoeven camiel.vanderhoeven at
Tue Aug 8 00:24:33 CDT 2017

On 8/7/17, 10:35 PM, "cctalk on behalf of Mark J. Blair via cctalk"
<cctalk-bounces at on behalf of cctalk at> wrote:

>> On Aug 7, 2017, at 12:13 AM, Camiel Vanderhoeven
>><camiel.vanderhoeven at> wrote:
>> That would have been the CPU cabinet for the C240 (which is twice as
>> as the C220¹s CPU cabinet. The C240¹s CPU consumes - i.e. converts to
>> - about 20 kilowatts of power, so that would indeed have created a
>> in a computer room. It will surely create a hotspot in my barn!
>Ok, that makes sense. All I remember is that from the rear side of the
>cabinet, it was behind the exhaust vents at the lower right corner that
>was the optimal place in the computer room to curl up in a fetal position
>at 6AM, when the main building A/C came on and the computer room
>temperature plummeted, right about when the metabolism of an exhausted
>college student working a graveyard computer operator shift was at
>minimum. But it was all worth it for a key to the computer room, and
>unlimited root access on Sun workstations when most students were lucky
>to get a small quota on the heavily-loaded Sequent Symmetry series
>machine. Oh, and they paid me, too. :)

Lower right corner when seen from the back sounds right, as the CPU
cabinets are usually on the left on these machines. I guess there’s no
reason they couldn’t be on the other side, but in all the pictures I’ve
ever seen - as well as on my machines - the CPU’s on the left.

It sounds like you had the same student job at your university as I had at
mine. One of the job perks for me was that I got to take a decommissioned
supercomputer (Alliant FX/2800) home :-)

>That C240 also had the nicest 9-track drive in the room. Most of my tape
>mounts were on the TU77 next to the VAX-11/780 (or maybe 785?), but I
>always liked working with that drive on the C240. I no longer recall
>which company manufactured its transport, but it was really fast.

It was made by STC (Storage Technology Corporation), which is owned by
Oracle, and known as StorageTek these days. It uses a STC-proprietary
interface, and Convex built their own interface board for high-speed
operation for it. One of the ways they got it to run fast was to use very
large blocks (which not all tape drives can read, as I found out when I
was making images of the tapes I have!)


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