My things

 

Based on a LinkedIn post originally published on 20 February 2026 In the late 1990s, I was supporting a department store in north-eastern Brazil whose entire technical environment was built around SCO UNIX. The architecture was typical of that period: a central SCO UNIX host; numerous serial terminals; printers attached locally to some of those terminals; and point-of-sale software written in COBOL and running directly on the UNIX system. It was a compact and highly centralised environment. The terminals provided the user interface, while the host performed the application processing and controlled the operational workflow. The business needed what initially sounded like a simple enhancement: allow printing to occur in the background without interrupting the interactive terminal sessions used by the cashiers. In practice, this was far from simple. One serial connection, two simultaneous responsibilities Each terminal communicated with the SCO UNIX host through a serial connection. Some...

Security in this platform follows a strict deny-by-default model across the entire stack. No service is reachable merely because it has been installed, enabled or assigned a network interface. Every exposed service must have a clear operational purpose and an explicitly defined path to the systems that need it. This principle is particularly important for the front-end data store node, HG000009. The system participates in several distinct network roles, but that does not mean those networks should be able to communicate through it. Core security principle: connectivity is granted for a specific purpose, between specific systems, over specific interfaces. Everything else remains unavailable. Network interfaces do not imply network transit A host connected to several network segments can easily become an unintended routing point. This can happen through an explicit configuration change, an operating-system default, an incorrectly applied automation task or a temporary troubleshooting a...

 

 

One of the most challenging aspects of applying for senior positions today is not rejection itself. Rejection is an unavoidable part of any competitive hiring process. The more serious problem is what frequently follows it: the absence of actionable feedback . After investing time in understanding an organisation, tailoring an application and participating in its selection process, candidates are often left with little more than a standard message stating that another applicant was considered a closer match. In one case, the only explanation I received was: “German law makes it difficult for employers to provide applicants with comprehensive feedback without fear of repercussions at a later date.” I understand the legal and risk-management concerns behind that position. Employers may worry that detailed comments could be misunderstood, disputed or used as the basis for a complaint. Nevertheless, this exposes a structural weakness in many modern recruitment processes: The learning loop ...

 

Based on a LinkedIn post originally published on 13 February 2026 In the early 1990s, while working for a technology company in southern Brazil, I became responsible for producing the company’s technical newsletter. This was before modern ticketing systems, searchable knowledge bases, internal portals and widespread internet access. We supported customers using our business software and the infrastructure on which it operated. Questions and problems arrived through telephone calls, handwritten notes, fax messages and on-site visits. The objective of the newsletter was practical: Capture the problems customers encountered repeatedly and turn the solutions into reusable operational knowledge. Today, we might call the result a knowledge base, a living FAQ or a collection of operational runbooks. At the time, it was a newsletter distributed on floppy disks or printed and physically mailed to customers. The technology was limited. The underlying knowledge-management model was remarkabl...

 

 

My views Log Episode 0 - 2026-Feb-14 Episode 1 - 2026-Feb-16 Episode 2 - 2026-Feb-16 Episode 3 - 2026-Feb-16 Episode 4 - 2026-Feb-26 Episode 5 - 2026-May-09 Episode 6 - 2026-May-09 Episode 7 - 2026-May-09 Episode 8 - 2026-May-09

  Log Episode 1 - 2026-Feb-27 Episode 2 - 2026-Mar-19 Episode 3 - 2026-Mar-19 Episode 4 - 2026-Mar-20 Episode 5 - 2026-Apr-07 Episode 6 - 2026-Apr-08 Episode 7 - 2026-Apr-20 Episode 8 - 2026-Apr-20 Episode 9 - 2026-Apr-27 Episode 10 - 2026-May-07

Log Episode 1 [2025-Dec-08] - 2026-May-06 Episode 2 [2025-Dec-15] - 2026-May-06 Episode 3 [2025-Dec-22] - 2026-May-07 Episode 4 [2025-Dec-29] - 2026-May-07

Based on a LinkedIn post originally published on 11 February 2026 On HG000009, the front-end data store node in my home lab, memory is treated as a first-class performance component. It is not regarded as spare capacity waiting for an application to claim it. Memory is an active part of the storage architecture. It affects read performance, metadata access, latency, recovery behaviour and the system’s ability to remain predictable under changing workloads. In this design, ZFS acts as the central storage control plane. Back-end devices are aggregated through ZFS, which then provides controlled storage services to consumers through iSCSI targets and, where appropriate, SMB shares. ZFS is used for more than filesystem semantics. It provides data integrity, caching, snapshots and an explicit operational model for the storage platform. Memory plays a critical role in making those capabilities perform consistently. Unused memory is not necessarily wasted memory Traditional capacity thinking ...

Today we decided to do something that was probably more about curiosity than tourism. We drove to Tiraspol. From Chișinău, this is not an international journey in the conventional sense. According to Moldova and almost the entire international community, Tiraspol is part of the Republic of Moldova. In practice, however, travelling there means entering territory controlled by the self-proclaimed Pridnestrovian Moldavian Republic, with its own authorities, police, border procedures, currency and political symbols. It is one of those peculiar situations where the political map and the experience on the ground do not entirely agree. I had wanted to see it for myself. And by the end of the day, one impression dominated all the others: I had never been to the Soviet Union, but this was probably the closest I will ever get. The journey east The first surprise was not Tiraspol itself. It was getting there. ...