16. Usage modes

The REDAC system is still in development, and thus are the usage modes. Despite we have a single user mode in mind which solely goes via a single entrypoint, which does scheduling, load balancing and the like, in special situations a number of different usage modes are supported in the moment. A graphical overview in a block schema diagram is provided in Fig. 16.1 and subsequentialy discussed.

schema drawing

Fig. 16.1 The different inofficial user access variants for REDAC

16.1. Queue access

The primary access is indirected by the Redaccess (Middleware) via HTTP and REST. This way, ordinary encrypted HTTPS can be used and the regular Authentification methods can be employed. Therefore, this access method is the only one which is advertised in the REDAC user manual.

16.2. Immediate SuperController access

The immediate mode access to the Pybrid Proxy is technically only possible when being within the Internal network. This is for instance possible via a VPN solution or with appropriate firewall rules from outside. It is important to note that in this mode, no user authentification is applied, computing time is not accounted and the TCP connection to the SuperController is not encrypted. Furthermore, the protocol is no more HTTP but the specific JSONL protocol which is documented in the pybrid and firmware documentations.

This immediate mode can be interesting for debugging, for experienced users, in particular single system users. Users are suggested to use the pybrid python package to connect to the pybrid proxy.

16.3. Immediate Microcontroller access

In this variant, even the SuperController is short-circuited and users directly access the mREDAC-embedded microcontrollers. This is possible if users are part of the Internal network (see previous section). However, as a drawback to the immediate SuperController access, in this mode users can not make use of the global synchronization line. That means that synchronized computations accross more then a single mREDAC are not possible.

This kind of access is strongly discouraged whenever any part of the higher level software abstraction is active, i.e. even if the pybrid proxy is active. If users want to make use of this access mode, they should use the pybrid or lucipy sofware packages in order to address the mREDAC boards.

16.4. JupyterHub/Browser access

JupyterHub is a hosted computation software provided by Anabrid Operations. It is basically a hybrid mode which allows all kind of uses. It combines a number of advantages:

  • User does not need to install any software/development environment locally. He finds the open source scientific programming environment jupyter readily available in browser, comparable to Matlab.

  • Regular queue access is possible

  • However, also direct access is possible if neccessary since the instance has access to the REDAC internal network.