title: Computers in Praha
date: 2023-05-03

![cell-site-in-praha](/img/b/praha-cell-site.jpg)

## Open Compute

Watercooled and Open Rack V3 chassis + racks were displayed in the exposition
hall:

- Prototype of a 3U liquid cooled Nokia AirFrame Edge chassis.
- Qarnot server: around 20 units are deployed per site, for an average of 240
  motherboards.
- HPE latest ARM server with an Ampere cpu: RL300, supporting
  [OpenBMC](https://en.wikipedia.org/wiki/OpenBMC).

## Frontier

This is [the world's first and fastest supercomputer](https://en.wikipedia.org/wiki/Frontier_(supercomputer)).
I have visited one of the assembly line and server room used in the fabrication
process.

### Components

The chassis are 1U tall, composed of two servers spread on one motherboard,
with a total of 8 cpus. The BMCs are on one extension card, directly plugged
on one side of the motherboard, and connected via a cable to the opposite side
for controlling the second server.

The chassis are stacked at the backside of the rack, while the power units and
water pipes are present at the fronside.

Note that each power unit can draw up to 15KW and is vertically plugged in the
rack.

### Water leaks

Big drainage pipes circulate above the racks, probably the closed water loop.
Huge recipients with water detectors are present underneath, avoiding the
fluid to fall down over the chassis.

Thin conductive wires are also present in each chassis. They seem to be
connected to the motherboard or BMCs extension card. This helps to detect any
internal leak and gracefully shutdown the servers.